Multilayer Ltcc Bandpass Filter for Microwave Applications - Thesis

SIM UNIVERSITY SCHOOL OF SCIENCE AND TECHNOLOGY

MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS

STUDENT

: GUO LING (Q0704929) SUPERVISOR : DR. LUM KUM MENG PROJECT CODE : JAN2011/ENG/03

A project report submitted to SIM University in partial fulfilment of the requirements for the degree of Bachelor of Engineering (or Bachelor of Electronics) JANUARY 2011 1|Page

Abstract Microwave devices in the consumer electronics market are continuously developing with size, cost and performance being all-important factors for the success of these devices and hence, device and component manufacturers have to constantly seek new advanced integration, packaging and interconnection technologies. A bandpass filter, which is an essential device in microwave devices, is relatively large in size as compared to other components hence it is important to choose the right filter design methodology which fulfils both the requirements of size reduction and ease of integration with other circuit components. The use of Low Temperature Co-fired Ceramic (LTCC) technology fulfils both these conditions as LTCC substrate offers excellent electrical and mechanical properties. It also offers ease of integration with other passive elements. For this project, the design of multilayer LTCC bandpass filter with a centre frequency of 2.513GHz has been proposed. DuPont 951 substrate with a relative permittivity of 7.8, a loss tangent of 0.002 and substrate height ranging from 0.045mm to 0.28mm is chosen as the material used for the filter prototype, which is designed and simulated using Agilent ADS Software. The resultant filter response is analyzed to determine if requirements are met. The filter design was then modified to use FR4-86 substrate instead due to the complexity and high cost involved with using DuPont 951 substrate for fabrication, FR4 substrate has a relative permittivity of 4.7, a loss tangent of 0.016 and height of 1600 um. The new filter design using FR4-86 substrate has a centre frequency of 1.458GHz and its response is modelled to match the response of the initial filter design using DuPont 951 substrate. The filter design using FR4-86 substrate is then fabricated and subsequently assembled with SMA connectors. By using Agilent Network Analyzer E5062A, the filter response of the fabricated filter prototype is measured and a comparison analysis is performed between the measured results vs. the simulated results.

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Acknowledgements Throughout the course of this project, I have met and overcome various setbacks and these are the very people who have helped and guided me through those difficult times, and made the completion of this project possible. I would like to extend my heartfelt gratitude to firstly, my project supervisor, Dr. Lum Kum Meng, for his trust, patience, encouragement and utmost support; my wonderful project mates, Mr. Lee Meng Long, Mr. Michael Ng and Mr. Toh Wen Jie for their much needed inspiration and help in whatever form required and finally, to my dearest family and loved ones, who stood by me throughout with unwavering love and support.

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Table of Contents Abstract ...................................................................................................................................... 2 Acknowledgements .................................................................................................................... 3 Table of Contents ....................................................................................................................... 4 Index of Tables ......................................................................................................................... 10 1.

2.

3.

INTRODUCTION ........................................................................................................... 11 1.1

Project Objectives ...................................................................................................... 11

1.2

Overall Objectives ..................................................................................................... 11

1.3

Layout of Project Report ........................................................................................... 12

PROJECT MANAGEMENT ........................................................................................... 13 2.1

Work Breakdown Structure (WBS) ........................................................................... 13

2.2

Time Allocation ......................................................................................................... 14

2.3

Project Plan (Gantt chart) .......................................................................................... 16

2.4

Monitor and Review .................................................................................................. 17

2.5

Resources Required ................................................................................................... 17

2.6

Risk Management ...................................................................................................... 18

INVESTIGATION OF PROJECT BACKGROUND ...................................................... 19 3.1

Literature Review on LTCC Technology ................................................................... 19

3.1.1

Brief Historical Review .................................................................................... 19

3.1.2

What is LTCC Technology? ............................................................................. 20

3.1.3

Advantages of LTCC Technology .................................................................... 23

3.1.4

Process of LTCC Technology ........................................................................... 24

3.1.5

Applications of LTCC Technology................................................................... 29

3.2

Literature Review on Microwave .............................................................................. 30

3.2.1

Microwave Frequency Bands ........................................................................... 31

3.2.2

Applications of Microwave .............................................................................. 32

3.3

Literature Review on Micro-strip Structure and Waves in Micro-strips ................... 32

3.3.1 Fringing Effects, Effective Dielectric Constant and Characteristic Impedance in Micro-strips .................................................................................................................. 33 3.3.2

Guided Wavelength and Physical Length of Micro-strips ............................... 34

3.3.3

Micro-strip Losses ............................................................................................ 35

3.4

Literature Review on RF Filter Design Methodologies ............................................ 36

3.4.1

Basic RF Filters ................................................................................................ 36

3.4.2

Micro-strip Bandpass Filter Designs ................................................................ 39

3.4.3

Network Variables and Scattering Parameters ................................................. 41

3.5

Agilent Advanced Design System (ADS) Software .................................................. 44

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3.5.1 3.6

Printed Wiring Board (PWD) Finishes ...................................................................... 45

3.6.1

Organic Solderability Preservative (OSP) ........................................................ 45

3.6.2

Hot Air Solder Levelling (HASL) .................................................................... 46

3.7 4.

Key Benefits of Agilent ADS Software ............................................................ 45

Network Analyzer ...................................................................................................... 48

PROJECT SELECTIONS ................................................................................................ 50 4.1

Substrate Material Selection ...................................................................................... 50

4.2

Selection of Software Simulator Tool ........................................................................ 51

4.3

Selection of Printed Wiring Board (PWB) Finishes .................................................. 51

4.4

Selection of Measurement Tool ................................................................................. 52

4.5

Selection of SMA Connector ..................................................................................... 52

5.

DEVELOPMENTS OF BANDPASS FILTER DESIGN ................................................ 54 5.1

Proposed Specifications of Initial LTCC Filter Design ............................................. 54

5.2

Proposed Configuration of Initial LTCC Filter Design ............................................. 54

5.3

Initial LTCC Filter Design and Simulation using Agilent ADS Software ................. 55

5.4

Simulation Results of Initial LTCC Filter Design ..................................................... 57

5.5

Enhanced LTCC Filter Design ................................................................................... 58

5.6

Simulation Results of Enhanced LTCC Filter Design ............................................... 59

5.7

Modelling of Filter Design using FR4-86 Substrate.................................................. 60

5.8 Re-modelled Initial Filter Design (FR4-86 Substrate) and Simulation using Agilent ADS Software ...................................................................................................................... 61 5.9

Simulation Results of Re-modelled Initial Filter Design (FR4-86 Substrate) ........... 63

5.10

Enhanced Re-modelled Filter Design using FR4-86 Substrate ............................ 64

5.11 Simulation Results of Enhanced Re-modelled Filter Design using FR4-86 Substrate............................................................................................................................... 65 5.12 6.

Critical Dimensions of Finalized Filter Design using FR4-86 Substrate.............. 66

FABRICATION AND ASSEMBLY OF FILTER PROTOTYPE .................................... 68 6.1

Exporting Gerber Files .............................................................................................. 69

6.2

Assembly of Fabricated Filter Prototype ................................................................... 73

7.

COMPARISON BETWEEN MEASURED AND SIMULATED RESULTS ................. 76 7.1

Measurement of Filter Responses .............................................................................. 76

7.2

Comparison Analysis between Measured and Simulated Results ............................. 78

8.

CONCLUSION ................................................................................................................ 80 8.1

9.

Suggestion for Future Work ....................................................................................... 80

CRITICAL REVIEWS AND REFLECTIONS ............................................................... 81

10.

REFERENCES .......................................................................................................... 82

11.

APPENDIX A ............................................................................................................ 85

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12.

APPENDIX B ............................................................................................................ 87

13.

APPENDIX C ............................................................................................................ 89

14.

APPENDIX D ............................................................................................................ 91

15.

APPENDIX E ............................................................................................................ 92

16.

APPENDIX F ............................................................................................................ 94

17.

APPENDIX G ............................................................................................................ 96

18.

APPENDIX H ............................................................................................................ 98

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Index of Figures Figure 1: Work Breakdown Structure (WBS) ........................................................................... 13 Figure 2: Resources required ................................................................................................... 17 Figure 3: Multilayered ceramic circuit board for mainframe computers produced by Fujitsu (Size 245 x 245mm, 52 layers) (Bar = 50 mm) ........................................................................ 20 Figure 4: Cross-sectional view of the circuit board with Cu in internal wiring (via diameter: 80µm. conducting line width: 80µm, line spacing: 100 µm, dielectric material thickness per layer: 200 µm) ......................................................................................................................... 20 Figure 5: Passive elements ...................................................................................................... 21 Figure 6: Differences between HTCC and LTCC .................................................................... 21 Figure 7: Evolving binding at melting of glass in LTCC glass-ceramic structure .................. 22 Figure 8: Complex LTCC circuit structure .............................................................................. 22 Figure 9: Why use LTCC? 1 = Good / 2 = Average / 3 = Bad ................................................ 23 Figure 10: Overall process of LTCC technology ..................................................................... 24 Figure 11: Raw glass-ceramic sheets ...................................................................................... 24 Figure 12: Result of laser punching with proper parameters: a) Plane of 200 µm diameter hole, lighted from above; b) Plane of the same hole, light from under; c) Worm’s-eye view of 200 µm hole, light from under; d) Raggedness of the edge of 200 µm diameter hole ............. 25 Figure 13: Filling via holes of LTCC circuits with vacuum-drawing...................................... 26 Figure 14: Schema of via-filling .............................................................................................. 26 Figure 15: Five typical types of delamination defects after firing: a) Vertical spitting; b) Internal interlayer delamination; c) Stepped interlayer delamination; d) Surface blistering; e) Circular delamination .............................................................................................................. 27 Figure 16: Heat profile of DuPont 951 Green Tape: 1) Warm up; 2) Keep temperature; 3) Warm up; 4) Keep temperature; 5) Cooling ............................................................................ 28 Figure 17: Shrinkage of LTCC substrate caused by firing ...................................................... 28 Figure 18: Structure of stripline configuration filter with LTCC ............................................ 31 Figure 19: Microwave frequency bands .................................................................................. 31 Figure 20: General micro-strip structure ................................................................................ 33 Figure 21: Waves in micro-strip structure ............................................................................... 33 Figure 22: Loss Tangent effects on S11 and S21...................................................................... 35 Figure 23: Configuration of micro-strip enclosure ................................................................. 36 Figure 24: Frequency behaviour of four basic filter types ...................................................... 37 Figure 25: Attenuation profile of Butterworth and Chebyshev filters ..................................... 38 Figure 26: Typical architecture of a multilayer design............................................................ 39 Figure 27: General configuration of an End-Coupled, half wavelength resonator filter........ 39 Figure 28: General configuration of a Parallel-Coupled, half wavelength resonator filter ... 40 Figure 29: General configuration of a Hairpin-Line bandpass filter ..................................... 40 Figure 30: General configuration of an Inter-Digital bandpass filter .................................... 41 Figure 31: Two-port network configuration ............................................................................ 41 Figure 32: Snapshots of S-parameters generated from Agilent ADS Software momentum ..... 44 Figure 33: Agilent ADS Software user interface...................................................................... 44 Figure 34: Typical OSP process .............................................................................................. 45 Figure 35: Typical HASL process ............................................................................................ 47 Figure 36: Basic blocks of a typical Network Analyzer ........................................................... 49 Figure 37: Agilent Network Analyzer E5062A ........................................................................ 52 Figure 38: Various SMA connectors ........................................................................................ 53 Figure 39: Cross-sectional view of initial LTCC filter design................................................. 54 Figure 40: Layout architecture of initial LTCC filter design .................................................. 55 7|Page

Figure 41: Defining substrate properties for initial LTCC filter design ................................. 55 Figure 42: Setting up of simulation control environment for initial LTCC filter design ......... 56 Figure 43: Defining port properties for initial LTCC filter design ......................................... 56 Figure 44: Layout structure of initial LTCC filter design ....................................................... 57 Figure 45: S11 response of initial LTCC filter design ............................................................. 57 Figure 46: S21 response of initial LTCC filter design ............................................................. 57 Figure 47: Cross-sectional view of enhanced LTCC filter design ........................................... 58 Figure 48: Layout architecture of enhanced LTCC filter design ............................................. 58 Figure 49: Layout structure of enhanced LTCC filter design .................................................. 59 Figure 50: S11 response of enhanced LTCC filter design ....................................................... 59 Figure 51: S21 response of enhanced LTCC filter design ....................................................... 59 Figure 52: Cross-sectional view of re-modelled initial filter design (FR4-86 substrate)........ 60 Figure 53: Layout architecture of re-modelled initial filter design (FR4-86 substrate) ......... 61 Figure 54: Defining substrate properties for re-modelled initial filter design (FR4-86 substrate).................................................................................................................................. 61 Figure 55: Setting up of simulation control environment for re-modelled initial filter design (FR4-86 substrate) ................................................................................................................... 62 Figure 56: Defining port properties for re-modelled initial filter design (FR4-86 substrate) 62 Figure 57: Layout structure of re-modelled initial filter design (FR4-86 substrate) .............. 63 Figure 58: S11 response of re-modelled initial filter design (FR4-86 substrate) .................... 63 Figure 59: S21 response of re-modelled initial filter design (FR4-86 substrate) .................... 63 Figure 60: Cross-sectional view of enhanced re-modelled filter design (FR4-86 substrate) .. 64 Figure 61: Layout architecture of enhanced re-modelled filter design (FR4-86 substrate) .... 64 Figure 62: Layout structure of enhanced re-modelled filter design (FR4-86 substrate) ......... 65 Figure 63: S11 and S21 responses of enhanced re-modelled filter design (FR4-86 substrate) .................................................................................................................................................. 65 Figure 64: Overall dimensions of finalized filter design using FR4-86 substrate; same dimensions to be used for first and fifth layer (ground plane)................................................. 66 Figure 65: Critical dimensions of second layer (Parallel-Coupled resonator)....................... 66 Figure 66: Critical dimensions of third layer (Parallel-Coupled resonator) .......................... 66 Figure 67: Critical dimensions of fourth layer (left and right “triangle” resonators connected by micro-strip).......................................................................................................................... 67 Figure 68: Multilayer bandpass filter prototype layout .......................................................... 68 Figure 69: “Cond” layer ......................................................................................................... 68 Figure 70: “Cond2” layer ....................................................................................................... 68 Figure 71: "Resi" layer ............................................................................................................ 69 Figure 72: “Diel” layer ........................................................................................................... 69 Figure 73: “Resi” layer without Input / Output ports ............................................................. 69 Figure 74: "Cond" layer with border....................................................................................... 70 Figure 75: "Cond2" layer with border..................................................................................... 70 Figure 76: "Resi" layer with border ........................................................................................ 70 Figure 77: "Diel" layer with border ........................................................................................ 71 Figure 78: "Export Gerber Options" window.......................................................................... 71 Figure 79: Step-by-step guide in exporting Gerber files ......................................................... 72 Figure 80: Comparison between a) Conductor layers of the designed filter in Agilent ADS Software; b) Actual fabricated layers using HASL finishing ................................................... 73 Figure 81: Agilent Network Analyzer E5062A ........................................................................ 76 Figure 82: 2 x BNC adaptors with 50  termination ............................................................. 76 Figure 83: 2 x BNC to SMA cables .......................................................................................... 76 Figure 84: Connection of BNC end of cable to BNC adaptors on Agilent Network Analyzer 8|Page

E5062A..................................................................................................................................... 77 Figure 85: Connection of SMA end of cable to SMA connectors on fabricated filter prototype .................................................................................................................................................. 77 Figure 86: S11 response of fabricated filter prototype ............................................................ 78 Figure 87: S21 response of fabricated filter prototype ............................................................ 78 Figure 88: Simulated filter responses from Agilent ADS Software .......................................... 78

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Index of Tables Table 1: Time allocation........................................................................................................... 14 Table 2: Project plan (Gantt chart) ......................................................................................... 16 Table 3: Risk matrix ................................................................................................................. 18 Table 4: Applications of LTCC technology in market .............................................................. 30 Table 5: Properties of S-parameters ........................................................................................ 43 Table 6: Substrate material selection criterions ...................................................................... 50 Table 7: Substrate materials from various suppliers ............................................................... 50 Table 8: Substrate materials score chart ................................................................................. 51 Table 9: Software simulator tool selection criterions .............................................................. 51 Table 10: Pros / Cons of OSP and HASL Finishes .................................................................. 51 Table 11: Measurement capabilities of E5062A ...................................................................... 52 Table 12: Proposed specifications of initial LTCC filter design .............................................. 54 Table 13: Proposed specifications of re-modelled initial filter design (FR4-86 substrate)..... 60 Table 14: Step-by-step guide in assembling the filter prototype .............................................. 75 Table 15: Comparison table between measured vs. simulated results ..................................... 79

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1. INTRODUCTION Difficulties in transmitting information end-to-end have always existed in the early days due to the severe limitations of communication devices. This has led to a widespread interest from various parties in the research and development of communication devices in hopes of enhancing the capabilities. In the current world that we live in, there is huge demand for all things to be small. In the case of communication systems, it was also no longer good enough to be just wireless; being small is the key and is essentially what is driving today’s technology. In order to meet the demands, evolution of compact, high reliability and performance components was necessary to feed the advancement of wireless communication devices. This report proposes the design of a multilayer LTCC bandpass filter in order to meet the demands of being compact in size and ease of integration with other circuit components while not comprising on the quality in performances and reliability.

1.1Project Objectives The aim of the project is to design and fabricate a multilayer LTCC bandpass filter for microwave applications. The proposed filter is to be designed and simulation carried out to ensure that the desired filter responses are met. Once this is achieved, the proposed filter is then fabricated and the actual filter response is measured. A detailed comparison analysis will then be performed between the actual filter response and the simulated filter response.

1.2Overall Objectives The points below illustrate the overall objectives of this project:   

To research and understand the history and evolution of LTCC technology for microwave applications as well as the concepts, working principles advantages and applications behind this technology. To master and use Agilent Advanced Design System (ADS) software to perform modelling and simulation of filter designs. To utilize and improve project and time management skills.

I consider this project to be significant as LTCC technology offers the possibility of reducing the size of microwave devices tremendously without sacrificing performances, which is a critical factor in order to succeed in the increasingly competitive consumer electronics market. The possibilities of the use of LTCC technology are limitless and we can only wait to see what lies ahead in the evolution of LTCC technology.

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1.3Layout of Project Report Chapter 1: Introduction This chapter provides an introduction to the project as well as define the objectives of the project. It also provides a layout of the report, while the following chapters provide more in-depth explanations. Chapter 2: Project Management This chapter illustrates the project management process. All project management related activities will be highlighted in this chapter. Chapter 3: Literature Research This chapter illustrates on LTCC technology, microwave, micro-strip structure, RF filter design methodologies, Agilent ADS Software, PWB finishes and Network Analyzer. This is important as it highlights the fundamental concepts and principles for filter implementation. Chapter 4: Project Selections This chapter illustrates the selection criterions of different aspects in this project such as substrate materials, software simulator tools and etc. Chapter 5: Development of Bandpass Filter Design This chapter first illustrates the design of the filter prototype using LTCC technology and the subsequent simulation results. It then illustrates the modified filter design using FR486 and the subsequent simulated results. Chapter 6: Fabrication and Assembly of Filter Prototype This chapter illustrates the pre-fabrication process of exporting the Gerber files and the post-fabrication process of assembling the fabricated filter prototype. Chapter 7: Measured Results vs. Simulated Results This chapter illustrates the measurement procedures of the fabricated filter prototype and provides a comparison analysis between the measured and simulated filter responses. Chapter 8: Conclusion This chapter provides the conclusion of the project and covers some recommendations for future work. Chapter 9: Critical Review and Reflections This chapter provides a collective project after thoughts in which the experience gained during the entire duration of the project is shared.

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2. PROJECT MANAGEMENT Effective project management will be one of the most crucial factors in achieving objectives within the allocated time and resources. The chapter illustrates how the project is managed and executed. The first step in project management is to identify all the tasks required, the resources allocated and also the possible risks involved. The next step is to formula a plan, allocate a suitable amount of resources to each task and manage the risks involved to reduce the occurrence. The final but most important step is to perform continuous monitoring and review of the progress. Project Supervisor will also be updated regularly on the progress via emails, teleconferences or during meet up sessions. It would be important to tap the valuable experience of the Project Supervisor and hence, all major design issues, problems and decisions will be discussed and reviewed together.

2.1Work Breakdown Structure (WBS) A work breakdown structure (WBS) is used to decompose the project into smaller components to define and group tasks so as to organize and define the total work scope of the project

Figure 1: Work Breakdown Structure (WBS)

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2.2Time Allocation Duration Group Management

Proposal

Resource Monitor & Review Report

Oral Presentation

Requirements

Filter Designs

Fabrication Measurement

Literature Research

Tasks Draft Proposal Proposal Review Finalized Proposal Submit Proposal Resource Evaluation Resource Selection Draft Interim Report Interim Report Review Finalized Interim report Submit interim Report Draft Final Report Final Report Review Finalized Final Report Submit Final Report Draft Poster Poster Review Finalized Poster Submit Poster Printing of Poster Preparation of Presentation Slides Actual Presentation Conduct Research Evaluate Research Findings

Design Requirements Fabrication Requirements LTCC Filter Determine Specifications of Key Design Parameters Design and Analyze Simulated Results Finalize Filter Design FR4-86 Filter Determine Specifications of Key Design Parameters Design and Analyze Simulated Results Finalize Filter Design Fabricate FR4-86 Final Filter Design Assembly and Solder Connectors Measure Actual Filter Response using Network Analyzer Analyze Measured Results

Table 1: Time allocation

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(Days) 20 2 2 1 2 1 294 16 2 2 1 137 4 3 1 7 4 3 1 7 7 1 110 93 101 52

Start Date (DD-MMYYYY) 12/2/2011 4/3/2011 6/3/2011 7/3/2011 18/2/2011 20/2/2011 12/2/2011 19/4/2011 5/5/2011 7/5/2011 9/5/2011 23/6/2011 7/11/2011 11/11/2011 14/11/2011 31/10/2011 7/11/2011 11/11/2011 14/11/2011 15/11/2011 26/11/2011 3/12/2011 12/2/2011 1/3/2011 3/3/2011 22/6/2011

End Date (DD-MMYYYY) 3/3/2011 5/3/2011 7/3/2011 7/3/2011 19/2/2011 20/2/2011 2/12/2011 4/5/2011 6/5/2011 8/5/2011 9/5/2011 6/11/2011 10/11/2011 13/11/2011 14/11/2011 6/11/2011 10/11/2011 13/11/2011 14/11/2011 21/11/2011 2/12/2011 3/12/2011 1/6/2011 1/6/2011 11/6/2011 12/8/2011

3

3/3/2011

5/3/2011

86 2

6/3/2011 31/5/2011

30/5/2011 1/6/2011

10

2/6/2011

11/6/2011

60 2 28 10 5 5

12/6/2011 11/8/2011 13/8/2011 10/9/2011 20/9/2011 25/9/2011

10/8/2011 12/8/2011 9/9/2011 19/9/2011 24/9/2011 29/9/2011

The tasks involved are separated into five main groups, each focusing on a specify area of the project. Management This group consist of tasks related to project management. It includes:      

The proposal of the project which defines the objectives and purpose of the project. This provides the main direction of the project. Time management and resources required for the project. Risk management to identify all the risks and how they will be handled. Constant monitoring and review of progress via regular conferences with Project Supervisor. Report writing to provide a documentation of the project. Oral presentation of project findings.

Requirements This group consist of identifying the deliverables of the project. It includes:  

Literature research on the background of related topics. This will help in deciding the type of filter to be designed for the project. Identifying the design and fabrication requirements. This will better illustrated the deliverables in technical terms.

Filter Designs This group consist of how the deliverables will be achieved. It includes:  

LTCC filter design which consists of determining the specifications of the key parameters, designing the filter, analysis the simulated results and finalizing the filter design. FR4-86 filter design which also consists of determining the specifications of the key parameters, designing the filter, analysis the simulated results and finalizing the filter design.

Fabrication This group consist of the actual implementing of the filter prototype. It includes:  

Fabrication of the filter prototype. Assembly of filter prototype and soldering of connectors.

Measurement This group consists of verifying the deliverables. It includes:   15 | P a g e

Measuring the actual filter response of the fabricated filter prototype. Comparison analysis between the measured and simulated

results.

2.3Project Plan (Gantt chart)

Table 2: Project plan (Gantt chart)

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2.4Monitor and Review The project will follow a strict schedule and provide detailed timely updates to the Project Supervisor. The Work Breakdown Structure and the timeline will serve as the guide to monitor the progress of the project. During the meetings, the timeline will be reviewed to check if the project progress is still in line with the planning. Necessary adjustments will have to be made if there are slippages. Whenever there is a major design decision to be made, the Project Supervisor will be consulted so as to seek his advice on the matter. It is important to seek a second opinion from an experienced individual like the Project Supervisor to ensure that the project do not go off track. Please refer to Appendix H for the Meeting Logs.

2.5Resources Required The following table shows the resources required for the completion of this project.

Figure 2: Resources required

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2.6Risk Management It is important to identify all potential risk(s). Each risk will be accessed to determine the risk level, impact and possible solution(s). A Risk Matrix will be tabulated and reviewed frequently with the Project Supervisor.

Table 3: Risk matrix

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3. INVESTIGATION OF PROJECT BACKGROUND 3.1Literature Review on LTCC Technology One of the most promising integration technologies is the multilayer Low Temperature Co-fired Ceramic (LTCC) technology. Passive components, such as inductors, capacitors and filters, can be integrated into the multilayer LTCC substrate using this technology. The product is based on a glass-ceramic composite and components are made up of several layers of green sheets with the required circuits printed on them. These layers are processed in parallel and are stacked accurately prior to firing. LTCC technology for microwave applications plays an important role in the development of future electronic devices in high frequency applications for IC packaging radar, antennas and wireless technologies. In wireless applications, the integration of passive components corresponds to the trend of mobilization and miniaturization with high electrical performance using conductive electrode materials such as gold, silver and copper. 3.1.1

Brief Historical Review

The origin of multilayer ceramic substrate technology is said to lie in developments at RCA Corporation in the late 1950s, and the bases of current process technologies (greensheet fabrication technology, via forming technology, and multilayer laminate technology using the doctor blade method) were discovered at this time. Thereafter, progress was made using these technologies with IBM taking the lead and the circuit board (board size: 9cm2, with 33 layers, and 100 flip chip bonded LSI components) for IBM’s mainframe computer commercialized in the early 1980s was the inheritance. Since this multilayer board was co-fired at the high temperature of 1600 °C with the alumina insulating material and conductor material (Mo, W, Mo-Mn), it is called High Temperature Co-fired Ceramic (HTCC) to distinguish it from the Low Temperature Co-fired Ceramics (LTCC) developed later. From the middle of the 1980s, efforts to increase the speed of the mainframe computers accelerated, and as the key to increasing computer performance, further improvements were made to multilayer ceramic substrates for high density mounting applications. By using finer wiring in order to increase wiring density in circuit boards for high density mounting, the electrical resistance of the wiring increase, and conspicuous attenuation of the signal occurs. Therefore it is necessary to use materials with low electrical resistance (Cu, Au or the like) for the wiring. In addition, which the flip chip method of connecting bare LSI components directly, poor connection of the interconnects may result if the thermal expansion of the board is not close to that of the silicon components (3.5 x 106 /°C), therefore an insulating material with low thermal expansion (ceramic) is desirable . Furthermore, to achieve high speed transmission of signals, it is necessary to ensure that ceramic has a low dielectric constant. By the early 1990s, many Japanese and American electronics and ceramics manufacturers had developed multilayer boards (LTCC) that met these requirements. Among them, Fujitsu and IBM were the first to succeed with commercial applications of multilayer substrates using copper wiring material and low dielectric constant ceramics. From the latter half of the 1990s to the present, the focus of applications has shifted to high frequency wireless for the electronic components, modules and so on used in mobile 19 | P a g e

communication devices, primarily mobile phones. For the multilayer circuit board, the low thermal expansion of ceramics was its biggest merit for the purposes of high density mounting of LSI components. However, for high frequency communications application, its low transmission loss is its key feature, and the low dielectric loss of ceramic gives it an advantage over other materials [1].

Figure 3: Multilayered ceramic circuit board for mainframe computers produced by Fujitsu (Size 245 x 245mm, 52 layers) (Bar = 50 mm)

Figure 4: Cross-sectional view of the circuit board with Cu in internal wiring (via diameter: 80µm. conducting line width: 80µm, line spacing: 100 µm, dielectric material thickness per layer: 200 µm) 3.1.2

What is LTCC Technology?

Young and technology-savvy consumers are constantly seeking for smaller, higher quality, more reliable, faster operation speed and lower cost electronics apparatus such as mobile communication devices. This has led to the evolution in the manufacturing industry of multichip modules and multi-layer structure components, whereby more than two wiring layers are required. The multilayer Printed Wiring Board (PWB) was hence developed, which allowed passive devices to be surface mounted as discrete elements. The subsequent advance in technology gave rise to the Embedded Passive Technology (EPT), which made it possible to integrate passive elements such as resistors and capacitors (created from film technology) into the inner layers. 20 | P a g e

Figure 5: Passive elements The advantages of having embedded passive elements as compared to surface mount devices (SMD) are as follows:      

Increase in reliability due to reduction in solder bonding. Reduction of elements to be placed and attached. Reduction of circuit sizes. Increase in signal propagation speed. Better electromagnetic immunity. Lower prime cost.

When it is necessary to use better material than plastic carrier, ceramics or glassceramics will be used. There are two types of raw ceramics to manufacture MultiLayer Ceramic (MLC) substrate:  

Ceramics fired at high temperature (T ≥ 1500 °C): High Temperature Co-fired Ceramic (HTCC). Ceramics fired at low temperature (T ≤ 1000 °C): Low Temperature Co-fired Ceramic (LTCC).

Figure 6: Differences between HTCC and LTCC The base material of HTCC is usually Al2O3 and HTCC substrates are row ceramic sheets. The material of the embedded layers can only be high melting temperature metals such as wolfram, molybdenum or manganese due to the high firing temperature of Al2O3 hence, resulting in the substrate being unsuitable to integrate passive elements. It is possible though to produce thick-film networks and circuits on the surface of HTCC ceramic. 21 | P a g e

HTCC substrates could be only manufactured by companies possessing ceramic technology and the breakthrough came about when the mixing of glass to slurry resulted in the firing temperature of ceramic-glass substrate to be reduced to 850 °C so that the equipment for conventional thick-film process could be used. LTCC technology which evolved from HTCC technology inherited the advantageous features of thick-film technology. Because of the low firing temperature (850 °C), the same materials are used for producing buried and surface wiring and resistive layers as thick-film hybrid IC (i.e. Au, Ag, PdAg or Cu wiring RuO2 based resistive layers). It can be fired in an oxygen-rich environment unlike HTCC boards, where reduced atmosphere is used. Glass is chosen as the component due to fact that it crystallizes at the temperature of 850 °C as well as possessing high bend strength and good electrical parameters. During the co-firing process, the glass melts and the conductive and ceramic particles are sintered. The following figure shows the distribution of glass particles in LTCC glass-ceramic before and after firing.

Figure 7: Evolving binding at melting of glass in LTCC glass-ceramic structure Hybrid integrated circuits can be realized on the surface of the LTCC substrates and passive elements can be buried into the substrate. Semiconductor chips can be placed in a cavity and in some applications, embedded channels are shaped. The number of layers can be as high as 40. The following figure shows the structure of a complex circuit realized using LTCC technology [2].

Figure 8: Complex LTCC circuit structure

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3.1.3

Advantages of LTCC Technology

The LTCC technology avoids many disadvantages that others have and offers the following benefits [2]:                

Economizes multiple steps of the manufacture process compared with the conventional thick-film technology (parallel processing). Mass production methods can be really applied (several processing steps can be automated). Fabrication techniques are relatively simple and inexpensive. Tapes of different compositions can be manufactured with desired layer properties. Thermo-physical properties can be modified. Possibility of auto-packaged devices fabrication. Electronic circuits can be integrated, using its hybrid nature. Design and manufacture 3-dimensional circuits. Possibility of cutting the tape / substrate into different shapes. Because of the possibility to bury passive components within the substrate, it reduces the size of circuits (down to about 50 percent in comparison to the PCB). Number of signal layers almost unlimited. Ability to perform at frequencies over 30GHz. High resistance against ambient working temperatures (up to 350°C). Good thermal conductivity compared to PCBs (factor 10). Good match to semiconductor TCEs. Very good hermeticity of the substrate.

Figure 9: Why use LTCC? 1 = Good / 2 = Average / 3 = Bad

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3.1.4

Process of LTCC Technology

The LTCC process and HTCC process are basically the same except that HTCC processing requires additional steps such as complex firing conditions, flattening fires and plating steps [3].

Figure 10: Overall process of LTCC technology Slitting Greensheets are shipped on a roll most of the time. The tape has to be unrolled onto a clean, stainless steel table and cut with a razor, laser or a punch into parts (these parts have to be a little larger than the blank size, if the material needs to be preconditioned). If a laser is used, it is important to control the power to avoid firing of the sheets.

Figure 11: Raw glass-ceramic sheets

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Preconditioning Some of these tapes need to be preconditioned. What this means is that the greensheet has to be baked at 120°C for about 30 minutes depending on manufacturer and material. An example of this would be the DuPont GreenTape. These tapes are normally shipped with an applied foil or bake sheet, which has to be removed before the lamination process at the latest. This foil is sometimes used as a filling mask for the vias by some processors. Blanking Orientation marks and lamination tooling holes (and the final working dimension in case of preconditioned tapes) are created using a blanking die. It is important to note that it is preferred to rotate the single parts in turns of 90° to compensate for the different x/y-shrinking of the LTCC. Forming Vias Vias may be punched or drilled with a low power laser.

Figure 12: Result of laser punching with proper parameters: a) Plane of 200 µm diameter hole, lighted from above; b) Plane of the same hole, light from under; c) Worm’s-eye view of 200 µm hole, light from under; d) Raggedness of the edge of 200 µm diameter hole

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Filling Vias Vias can be filled with a conventional thick film screen printer or an extrusion via filler. In the former, the tape has to be placed on a sheet of paper lying on top of a porous stone and it is held in place by a vacuum pump which is also used as an aid for via filling. It is important to note that the possibilities of this method are limited as the vias must have a larger diameter than tape thickness and the smallest possible size of vias to be filled also depends on the viscosity of the paste. In the latter, the vias is filled up using a special extrusion via filler that works with pressures of about 4 – 4.5 bar. Both methods require a mask which should be made of 150 – 200 mm thick stainless steel. Another alternative is to use the Mylar-foil that the tape is usually applied on. For the filling of blind vias, it is advisable to form the holes concerned of the masks a little smaller than the diameter of the blind vias. Otherwise, problems might occur with the filling rate.

Figure 13: Filling via holes of LTCC circuits with vacuum-drawing

Figure 14: Schema of via-filling

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Printing A conventional thick film screen printer is used to print the co-fireable conductors and etc on the greensheet. The screens are standard (250 – 325) emulsion type thick film screens. A porous stone is also used to hold the tape in place. Due to the flatness and solvent absorption of the tape, printing of the conductor tends to be easier and of higher resolution than standard thick film on alumina. After printing, the vias and conductors have to be dried in an oven at 80 – 120°C for 5 – 30 minutes depending on material. Some pastes need to level at room temperature for a few minutes before drying. It is good to note that resistors may vary their value when terminated with different conductors. With the help of a Micro-Screen printer, it is possible to print conductors with a 50mm line resolution. Register for Lamination Each layer is placed in turns over tooling pins. Some processors use heat pliers to fix the sheets in turns one on top of the other. Lamination There are two methods of laminating tapes. The first method is called uniaxial lamination and the second method is called isostatic press. In uniaxial lamination, the tapes are pressed between heated platens at 70 °C, 200 bar for 10 minutes (typical values). This method requires a 180° rotation after half the time. The uniaxial lamination could give rise to problems with cavities / windows and also causes higher shrinking tolerances as compared to isostatic lamination. The main problem is the flowing of the tape resulting in high shrinkage tolerances (especially at the edge of the part) during the firing and varying thicknesses of single parts of each layer (causes hard problems on the high frequencies sector). In isostatic press, the stacked tapes are vacuum sealed in a foil and pressed in hot water. In isostatic press, only the pressure which is about 210 bar, is different when compared to uniaxial lamination. The other factors during the pressing process such as temperature and the duration are kept the same. It is important to note that after the lamination process, the substrate has deformation. Small amount of divergence from the prescribed parameters can cause delamination. The following figure shows the five typical types of delamination defects after firing.

Figure 15: Five typical types of delamination defects after firing: a) Vertical spitting; b) Internal interlayer delamination; c) Stepped interlayer delamination; d) Surface blistering; e) Circular delamination

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Co-firing Laminates are fired in one step on a smooth, flat setter tile. The firing should follow a specific firing profile hence the need for a programmable box kiln. A typical profile shows a slow rising temperature of about 2 – 5 °C per minute up to about 450 °C with a dwell time of about one to two hours, where the organic burnout (binder) takes place. The temperature is then raised up to 850 – 875 °C with a dwell time of about 10 to 15 minutes. The whole firing cycle lasts between three and eight hours depending on the material (large / thick parts cause the need of a modification to the firing profile). The following figure shows the heat profile of DuPont 951 Green Tape.

Figure 16: Heat profile of DuPont 951 Green Tape: 1) Warm up; 2) Keep temperature; 3) Warm up; 4) Keep temperature; 5) Cooling During firing, the LTCC substrates shrink and the value of it in case of DuPont 951 raw glass-ceramic is between 12% and 16% (+-0.2%) in the x and y axes and between 15% and 25% (+-0.5%) in the z axes (thickness). The following figure below shows the shrinkage of the substrate.

Figure 17: Shrinkage of LTCC substrate caused by firing It is important to note that resistor pastes need to have defined firing conditions (temperatures) else they vary enormously in value. 28 | P a g e

Post-firing Some materials need to be post-fired. What this means is that, after the first round of firing, the paste is to be applied followed by another round of firing. The post-firing conditions depend on the material used and vary broadly. It is important to note that resistor pastes need to have defined firing conditions (temperatures) else they vary enormously in value. Singulation If the fired parts have to be cut into smaller pieces or other shapes, there are three different methods to go about doing so. The first method which is also the most commonly used method is to use a post fire dicing saw. This method works very well for rectangular shapes, holds tight outside dimensional tolerances and allows high quality edges. The second method is to use an ultrasonic cutter. The final part shows low tolerances and may have unusually shapes. This process is also very slow and expensive. The third method uses a laser to cut the fired tape. The tolerances are tight but the qualities of the edges are poor. 3.1.5

Applications of LTCC Technology

The following table highlights some of the applications of LTCC technology used in the market [4]. S/N 1

Application Bandpass Filter

Frequency 24.5 – 25.5 GHz

2

Waveguide BP-Filter

40.5 – 41.5 GHz

3

Space: Power Distribution Network

19 GHz

4

Galileo EBG Patch Antenna

1.23/1.57 GHz

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Picture

5

Bluetooth Modules

2.45 GHz

6

FMCW Radar Sensor

24 GHz

7

WLAN Tx and Rx Modules with Antenna

60 GHz

8

Microwave package

DC – 40 GHz

9

Voltage Controlled Oscillator

23 – 26 GHz

10

SPDT Switch

40 – 45 GHz

11

Amplifier

21 – 27 GHz

Table 4: Applications of LTCC technology in market

3.2Literature Review on Microwave Essentially, microwaves are electromagnetic waves which travel in straight lines, like light waves. Their wavelength range from one millimetre to as long as one meter or equivalently, with frequency range between 0.3 GHz – 300 GHz. This includes the entire Super High Frequency (SHF) band (3 to 30 GHz, or 10 to 1 cm) as well as both the Ultra High Frequency (UHF) and Extremely High Frequency (EHF) band. In RF engineering, the upper boundary is normally specified to be around 100 GHz (3mm) with the lower boundary specified at 1GHz (30cm).

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When the wavelengths of signals are approximately the same as equipment dimensions, the apparatus and techniques may be described qualitatively as “microwave”, so that lumped parameter model is inaccurate. As a result, practical microwave technique tends to move away from the discrete capacitors, inductors and resistors which are used with lower frequency radio waves. Instead, transmission-line theory and distributed circuit elements are more useful methods for design and analysis. Open-wire and coaxial transmission lines give way to waveguides and stripline, and resonant lines or cavity resonators can be used to replace lumped-element tuned circuits. Effects of reflection, diffraction, scattering and atmospheric absorption usually associated with visible light are of practical significance in the study of microwave propagation. The same equations of electromagnetic theory apply to all frequencies [6].

Figure 18: Structure of stripline configuration filter with LTCC 3.2.1

Microwave Frequency Bands

Microwave spectrum is usually defined as electromagnetic energy ranging from approximately 1 GHz to 100GHz in frequency. Lower frequencies were included in older usages. Most common applications are within the 1 to 40 GHz range [6]. The different microwave bands are listed in the following table.

Figure 19: Microwave frequency bands 31 | P a g e

3.2.2

Applications of Microwave

The following are some of the applications of microwave [6]: Communication      

Wireless LAN protocols for example, Bluetooth. Metropolitan area networks for example, Worldwide interoperability for Microwave Access (WiMAX). Wide area mobile broadband wireless access. Mobile phone networks for example, GSM. Microwave radio used in telecommunication and broadcasting transmissions. Satellite communications system.

Radar 

Microwave radiation is used to detect the speed, range and other characteristics of remote objects for example, air traffic control.

Radio astronomy 

Active radar experiments with objects in the Solar system for example, determination of the distance to the Moon and mapping the invisible surface of Venus through cloud cover.

Navigation 

Global Navigation Satellite Systems (GNSS) for example, the Chinese Beidou, the American Global Positioning System (GPS) and Russian GLONASS.

Power 

Microwave heating used in industrial processes for example, to dry and cure products.

3.3Literature Review on Micro-strip Structure and Waves in Microstrips A micro-strip is a type of electrical transmission line which is used to convey microwave frequency signals. The figure below illustrates the general structure of a micro-strip. It consists of a micro-strip line with a width of W, and a thickness of t. The micro-strip line is placed on top of a dielectric substrate that has a thickness of h, and a relative dielectric constant of  r . This dielectric substrate is connected to the ground plane.

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Figure 20: General micro-strip structure The figure below shows clearly that the fields in the micro-strip are extended within two media, which are the air above and the dielectric below. The presence of these two guided-wave media causes the micro-strip structure to be inhomogeneous and modifies the mode of propagation to a non-TEM hybrid mode. This causes the propagation velocities to be dependent on the material properties, which are the permittivity  , the permeability  and dimensions of the micro-strip. According to [8], the non-TEM nature of the micro-strip is the result of the fringing components E x and H x at the dielectric-air interface.

Figure 21: Waves in micro-strip structure 3.3.1

Fringing Effects, Effective Dielectric Constant and Characteristic Impedance in Micro-strips

When the width W of the micro-strip is much smaller than the height h of the dielectric substrate, fringing effect will occur and cause the electric fields between the dielectric-air interface to vary and hence, resulting in a drift of the resonant frequency. It is therefore, very important to minimise this fringing effect and thus, the effective dielectric constant  re has been introduced to counter the effects of fringing. The closed form expression of  re and the characteristic impedance Z c given by [9] are as follows:

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For narrow micro-strip, W/h  1:

 re 

 r 1  r 1 

h  112  2 2  W

0.5



2  W    0.04  1  h   

(1)

 8h  W In   0.25  h 2  re  W where   120 ohms is the wave impedance in free space

Zc 

For wide micro-strip, W/h  1:   re  r 1  r 1 112 h 

2

2



0.5

(2)

W 1

W   W Zc  1.393 0.677In  1.444     h   re  h where   120 ohms is the wave impedance in free space

3.3.2

Guided Wavelength and Physical Length of Micro-strips

The physical length l of the micro-strip, which is known as the quarter wavelength and half wavelength micro-strip lines, can be obtained for the design of micro-strip filter once the effective dielectric constant  re is calculated. The physical length l of the micro-strip is calculated using the followings equations: For half wavelength micro-strip:

l

g

2 where  g is the guided wavelength

(3)

For quarter wavelength micro-strip:

l

g

4 where  g is the guided wavelength

(4)

The guided wavelength is expressed as:

0  re where 0 is the free space wavelength of the operating frequency f g 

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(5)

3.3.3

Micro-strip Losses

A micro-strip has three basic types of losses, conductor loss  c , dielectric loss  d and radiation loss. When designing a micro-strip filter, it is imperative to take note and account for these losses. Conductor Loss The expression for the attenuation contributed by the conductor loss  c is:

8.686Rs dB/unit length Z cW where Rs = surface resistance in ohms per square for the strip conductor and ground plane

c 

Rs can be expressed as:

0 2 where  = conductivity  = angular frequency 0 = permeability of free space = 4 x 10 7 Rs 

From these expressions, it can be concluded that a high conductivity material will suffer less attenuation. Dielectric Loss The expression for attenuation contributed by the dielectric loss  d is:

  re  1   r   tan     dB/unit length   r  1    re   g 

 d  8.686 

where  = loss tangent of the dielectric substrate The following figure illustrates clearly that the dielectric substrate with lower loss tangent will suffer from lesser attenuation.

Figure 22: Loss Tangent effects on S11 and S21

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Radiation Loss Due to the semi-open structure of the micro-strip, any radiation is either free to propagate away or to induce current on the metallic enclosure, causing radiation loss which is also known as housing loss. To minimise radiation loss, the height of the enclosure H should be at least eight times the substrate thickness h while the distance to the sidewalls L, should be at least five times the substrate thickness h.

Figure 23: Configuration of micro-strip enclosure

3.4Literature Review on RF Filter Design Methodologies RF and microwave filters are electronic filters that perform signal-processing functions to specifically enhance desired frequency components and remove undesired ones from signals operating in MHz – GHz frequency range. Let us kick off this section by briefly reviewing the four basic types of filters, low-pass filter, high-pass filter, bandpass filter and bandstop filter. This is followed by a discussion on the actual filter responses such as, Butterworth and Chebyshev filters. To cap it off, we will also discuss about the realization of RF filters. 3.4.1

Basic RF Filters

Let us kick off this section by briefly reviewing the four basic types of filters, lowpass filter, high-pass filter, bandpass filter and bandstop filter. This is followed by a discussion on the actual filter responses such as, Butterworth and Chebyshev filters. We will also discuss about the realization of RF filters as well as multilayer design techniques.

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Low-Pass Filter 

Allows low-frequency signals to pass through and attenuates the signals with frequencies higher than the cut-off frequency.

High-Pass Filter 

Opposite of low-pass filter. It allows high-frequency signals to pass through but attenuates the signals with frequencies lower than the cut-off frequency.

Bandpass Filter 

Allows frequencies within a certain range to pass through and rejects the signals with frequencies outside the range.

Bandstop Filter 

Passes most frequencies unaltered, but rejects those signals with frequencies in a specific range.

Figure 24: Frequency behaviour of four basic filter types 37 | P a g e

Butterworth Filter A Binomial or Butterworth filter is generally easy to implement as it possesses a monotonic attenuation profile. However, a higher order which requires more components is required in order to attain a steep attenuation transition from the pass to stop band. A steeper transition from the pass to stop band can be achieved if a certain degree of variations in the pass-band is permitted. Chebyshev Filter A Chebyshev filter has ripples that maintain at equal amplitude in either its pass-band or stop-band attenuation profile. It also has a steeper attenuation transition from the pass to stop band as compared to Butterworth filter. The following figure shows the attenuation profile of Butterworth and Chebyshev filter.

Figure 25: Attenuation profile of Butterworth and Chebyshev filters Realization of RF Filters In order to achieve a realizable filter, filter coefficients have to be de-normalized to meet realistic frequency and impedance requirements. In addition, the standard lowpass filter has to be transformed to the required filter types such as high-pass, bandpass or bandstop. This can be achieved using frequency transformation and impedance transformation. It is also important to note that realization of filter designs using discrete components beyond 500 MHz is extremely difficult as the wavelength becomes comparable with physical filter element dimensions. This results in various losses and degradation in circuit performance. Therefore, for practical realization of RF filters, the lumped component filters must be converted into distributed element realizations. Tools required to accomplish the conversion are namely Richard’s transformation and Kuroda’s identities, which are discussed by R. Ludwig and P. Bretchko [5]. 38 | P a g e

Multilayer Design Techniques When compared against the single layer technology, the multilayer technology is highly preferred because of advantages such as reduction in circuit dimensions, ease of fabrication and high integration density. A typical architecture of a multilayer design consists of a core material that has been laminated on both sites by a thin layer of copper metal which can be used as a distributed element for the circuit design. An epoxy layer is introduced to separate the signal layer and ground layer due to the fact that the circuit needs to be grounded. The circuit would normally be exposed to air in practice but however, the circuit would be simulated with the assumption that it is in an enclosed boundary. This will result in air being recognized as vacuum instead. The figure below shows the typical architecture of a multilayer design [33].

Figure 26: Typical architecture of a multilayer design 3.4.2

Micro-strip Bandpass Filter Designs

This section will describe briefly, the general configuration of some micro-strip bandpass filter types [9]. End-Coupled, Half Wavelength Resonator Filter The following figure shows the general configuration of an End-Coupled micro-strip bandpass filter. Each open-end micro-strip resonator is approximately a half guided wavelength long at the centre frequency of the band-pass filter. The coupling from one resonator to the other is through the gap between two adjacent open ends, and hence is capacitive.

Figure 27: General configuration of an End-Coupled, half wavelength resonator filter 39 | P a g e

Parallel-Coupled, Half Wavelength Resonator Filter The figure below shows the general configuration of the Parallel-Coupled micro-strip bandpass filter that uses half wavelength line resonators. They are positioned so that adjacent resonators are parallel to each other along half of their length. This arrangement provides a relatively large coupling for a given spacing between resonators, hence producing a wider bandwidth.

Figure 28: General configuration of a Parallel-Coupled, half wavelength resonator filter Hairpin-Line Bandpass Filter The following figure illustrates the general configuration of the Hairpin-Line bandpass filter. Hairpin-Line filter provides a compact structure, which is suitable for small size realization. They can be conceptually obtained by folding the resonators of the parallel-coupled micro-strip filter into a “U” shape. However, a full-wave EM simulation is required for accurate design of this filter.

Figure 29: General configuration of a Hairpin-Line bandpass filter

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Inter-Digital Bandpass Filter The figure below illustrates the general configuration of an Inter-Digital bandpass filter. It consists of an array of n TEM-mode or quasi-TEM-mode transmission line resonators, each having length of a quarter wavelength at the centre frequency. The resonators are short-circuited at one end and open-circuited at the other end with alternative orientation. Coupling is achieved by the way of the fields fringing between adjacent resonators separated by spacing Si,i 1 .

Figure 30: General configuration of an Inter-Digital bandpass filter 3.4.3

Network Variables and Scattering Parameters

The following figure shows a Two-port network which can be used to represent most microwave filters and filter components. The voltage and current variables at ports 1 and 2 are denoted as V1 , V2 , I1 and I 2 respectively while the terminal impedances at port 1, port 2 and the source or generator voltage are denoted as Z 01 , Z 02 and Es respectively.

Figure 31: Two-port network configuration

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The voltage and current variables are complex amplitudes when considering sinusoidal quantities and hence, the sinusoidal voltage can be represented by:





V1 t   V1 cos  t     Re V1 e j  t    Re(V1e j t )

where Re denotes “the real part of” the expression and the complex amplitude, V1 is defined by: V1  V1 e j

To analyze filter networks at microwave frequencies, incident waves an and the reflected waves bn are introduced. The relationship between the wave variables and the voltage and current variables are as follows: Vn  Z 0n (an  bn ) 1 (an  bn ) Z 0n

In 

or an 

1 Vn (  Z 0n I n ) 2 Z 0n

bn 

1 Vn (  Z 0n I n ) 2 Z 0n

where the subscript n = 1 or 2, representing ports 1 and 2 respectively The scattering or S-parameters can be used to describe and analyze the operation and electrical characteristic of microwave networks such as filters. Electrical properties of the network components that can be expressed using S-parameters are reflection coefficient, transmission coefficients, insertion loss, return loss, voltage standing wave ratio (VSWR), amplifier stability and gain. The S-parameters of a Two-port network defined in terms of wave variables are as follows: S11 

S21 

S22 

S12 

b1 a1 b2 a1 b2 a2 b1 a2

 a2  0

 a2  0

 a1  0

 a1  0

reflected

power at port 1

incident

power at port 1

transmitted

power at port

2

incident

power at port 1

reflected

power at port

2

incident

power at port

2

transmitted incident

power at port 1 power at port

2

where an  0 implies a perfect impedance match at port n

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The parameters S11 and S22 are known as reflection coefficients and S12 and S21 are the transmission coefficients. S-parameters are complex in general and their amplitudes are often represented in decibels (dB): 20 log S mn dB

where m, n = 1, 2 The reflection coefficients S11 and S22 can also be expressed in terms of terminal impedance ( Z 01 or Z 02 ) and input impedance ( Zin1 or Zin2 ) for network analysis and synthesis as: S11 

Zin1  Z 01 Zin1  Z 01

S22 

Zin2  Z 02 Zin2  Z 02

where Zin1 is the input impedance at port 1, Zin1  and Zin2 is the input impedance at port 2, Zin2 

V1 I1

V2 I2

The Insertion Loss, LA between the ports n and m and the Return Loss, LR at port n of a filter can be represented as: LA  20log Smn dB

where m, n = 1, 2 ( m  n ) LR  20log Snn dB

where n =1, 2 The voltage standing wave ratio (VSWR) which can be used instead of Return Loss is expressed by: VSWR 

1  Snn 1  Snn

Useful network analysis can be obtained with the above S-parameters. The table below shows several properties of S parameters [9].

Table 5: Properties of S-parameters

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The following graphs shows the S-parameters generated from Agilent ADS Software Momentum. For a good filter design, the reflection coefficient should be less than 10dB, the transmission coefficient should be close to 0dB and have a flat response. In addition, the filter network should also look symmetrical.

Figure 32: Snapshots of S-parameters generated from Agilent ADS Software momentum

3.5Agilent Advanced Design System (ADS) Software Agilent Advance Design System (ADS) Software is the leading electronic design automation software for Radio frequency, signal integrity applications and microwave. Agilent ADS software enjoys high usage by the leading companies in wireless communication and networking as well as in defence and aerospace industries. Agilent ADS software can be used as a high frequency design platform for LTE, WiMAX, radar and satellite [7].

Figure 33: Agilent ADS Software user interface 44 | P a g e

3.5.1

Key Benefits of Agilent ADS Software

The following points are the key benefits of using Agilent ADS Software [7]:   

Agilent ADS Software is a complete and integrated set of fast, easy to use and accurate system. Circuit and EM simulators enable first-pass design success in a complete desktop flow. Agilent ADS Software has application-specific Design-Guides which encapsulates years of expertise with a user-friendly interface. Agilent ADS Software is supported exclusively or months earlier than others by leading industry and foundry partners.

3.6Printed Wiring Board (PWD) Finishes This section will briefly describe the process cycle of Organic Solderability Preservative (OSP) and Hot Air Solder Levelling (HASL), which are the two commonly used finishes in the Printed Wiring Board (PWB) industry today. 3.6.1

Organic Solderability Preservative (OSP)

Organic Solderability Preservative (OSP) is the most widely used coating material in lead-free soldering due to its low cost, excellent solderability performances and easy processing method. An anti-oxidant film which is applied onto the exposed copper surfaces will establish a reaction with the copper, producing a form of organometallic layer known as the OSP. The coating thickness is approximately 0.1 to 0.5 microns. OSP has a shelf life of about six months. The flow diagram below illustrates a typical OSP process.

Figure 34: Typical OSP process

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Acid Cleaning An acidic cleaner solution is used to remove surface oils and soldermask residues from the exposed copper surfaces. This is to prepare the surface to ensure the controlled, uniform etching process in subsequent stages. Microetch Microetch solution, which typically consists of dilute Hydrochloric, Sulphuric, or Acetic acid, is used to process the board. This etching process removes remaining contaminants and chemically roughens the surface of the copper to promote adhesion. Air Knife Excess solution from the panel is removed via use of an air knife to minimise oxidation, formation and drag-in of sulfates on the copper surface prior to the OSP coating application. OSP A protective OSP layer is selectively deposited on the exposed copper surfaces by the OSP formulation in a water and acid bath. This chemically bonds the protective layer to the copper, forming an organometallic layer that preserves the solderability of the copper surface for future assembly. Air Knife Excess OSP from the panel is removed using an air knife to ensure even coating across the entire Printed Wiring Board (PWB) surface. This minimises the chemical losses through drag-out from the OSP bath. Dry The final stage of the OSP process is to use warm-air drying to cure the OSP coating and remove any residual moisture from the board. 3.6.2

Hot Air Solder Levelling (HASL)

Hot Air Solder Levelling (HASL) is a reliable technique used in the industry to ensure the solderability of PWB during fabrication and through assembly as it provides protection of the solderable surface from corrosion and contamination. It is a popular choice in the industry today due to its several benefits including its excellent shelf life (typically a year, under normal storage conditions). The flow diagram below illustrates a typical HASL process.

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Figure 35: Typical HASL process Pre-Clean Contaminants from the surface of the copper metal are removed using a microetch solution which consists of chemistries of Ferric Chloride, Sodium Persulfate or Peroxide Sulphuric. This is followed by water rinsing and hot air drying. Pre-Heat The panel is heated at typically 490F to 510F. The function of the pre-heating stage is to minimise thermal shock to the PWB when it is immersed in molten solder and also to prevent blocked or reduced holes. Flux Flux is used to provide adequate lubrication to the panel, promote coverage, wetting of the solder and when applicable, be compatible with oil blankets on the solder. Flux can be applied by immersion, rolls or spray. Solder Coating This is the actual application of the solder. Solder coating should be accomplished in the shortest possible time, typically less than 2 seconds, to provide adequate solder wetting with a thin layer of intermetallic compound (IMC). IMC bond is the formation of the base copper and the solder.

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Levelling A pressurized hot air knife is used to remove excess solder, level the remaining deposits and clear the holes of excess solder. The typical air temperature and air pressure used are 400F to 500F and 12 to 30 psi respectively. Cool Down The levelled molten solder must be allowed to cool down and solidify before the final stage of post-clean. This is to prevent panel warpage or thermal shock when entering the post-clean liquid. Post-Clean Post-cleaning is the final stage of the HASL process. The primary function of this stage is to remove any remaining flux from the surface of the PWB after levelling. Post-cleaning operation typically includes a detergent wash followed by a water rinse [22].

3.7Network Analyzer A network analyzer is a test instrument used to analyze the response of devices and components at RF or microwave frequencies. This analysis will allow engineers to understand how the devices will work within the RF circuit for which it is intended. Devices and components such as transistors, mixers, filters and frequency sensitive networks are characterized and measured using network analyzer. The three main types of network analyzers are: Scalar Network Analyzer (SNA) 

SNA is the simplest among the three types as it only measures the amplitude properties of the Device under Test (DUT).

Vector Network Analyzer (VNA) 

VNA is more useful compared to SNA as it is able to measure both amplitude and phase responses of the DUT.

Large Signal Network Analyzer (LSNA) 

LSNA is a highly specialized network analyzer used to investigate the characteristics of the devices under large signal conditions. It is able to examine the harmonics and non-linearity of a network under these conditions and provide a full analysis of its operations.

A typical network analyzer may be divided into four basic blocks, each with its own set of specialized functions. The following figure shows the four basic blocks of a typical network analyzer. 48 | P a g e

Figure 36: Basic blocks of a typical Network Analyzer In the RF network analyzer stimulus/source block, a signal is first generated and applied to the DUT to obtain its response. The stimulus or RF signal source is essentially a form of signal generator. There are generally two modes; one is to sweep the power level while the other is to sweep the frequency. The stimulus or RF signal is then pass to the signal separation section, where a portion of the incident signal is measured to provide a reference termed as “ratioing” using either a splitter or directional coupler. The incident and reflected travelling waves are also separated at the input of the DUT in this section using couplers or bridges. Next, a radio receiver with a demodulator or detector, in the receiver and detector section, is used to process the signal from the signal separation section to obtain the response of the DUT. The processed RF signal from the receiver and detector section is then displayed in a format that can be interpreted in the processor and display section. With the levels of processing available today, very sophisticated features are available in most modern network analyzers. These features included linear and logarithmic sweep, linear and log formats, polar plots, Smith charts, trace markers, limit lines and pass / fail criteria [8].

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4. PROJECT SELECTIONS 4.1Substrate Material Selection Various substrate materials, each with its own unique characteristics are available in the market. In order to select a suitable substrate material for the desired filter design, factors such as dissipation factor, dielectric constant, thermal coefficient of the dielectric constant and thickness of the substrate have to be considered. The cost of the material will also be a major factor if fabrication of the filter is required. The table below states the criterion for the selection.

Table 6: Substrate material selection criterions The following table shows the substrate material from various suppliers that are being considered for this project [24].

Table 7: Substrate materials from various suppliers A score chart is used to determine the substrate material to be used for the project. Please refer to Appendix A for detailed calculations of the score chart and Appendix B and Appendix C for the datasheets of DuPont 951 and FR4-86. Based on the results from the score chart below, DuPont 951AX-Ag will be chosen as the substrate for project simulation. However due to cost reasons, FR4-86 will be used for fabrication since it has the lowest cost ratio. 50 | P a g e

Table 8: Substrate materials score chart

4.2Selection of Software Simulator Tool Agilent Advance Design System (ADS) Software and Ansoft High Frequency Structural Simulator (HFSS) are two software simulator tools that can be used for designing and simulation of the desired filter design. The table below states the criterions for the selection.

Table 9: Software simulator tool selection criterions Agilent Advance Design System (ADS) Software has been chosen due to its low resource consumption requirement and the availability of free evaluation version. Features of Ansoft HFSS can be found in [25].

4.3Selection of Printed Wiring Board (PWB) Finishes The following table highlights the pros and cons of Organic Solderability Preservative (OSP) and Hot Air Solder Levelling (HASL) finishes. HASL will be chosen for the fabrication process.

Table 10: Pros / Cons of OSP and HASL Finishes 51 | P a g e

4.4Selection of Measurement Tool The Agilent Network Analyzer E5062A which is available in SIM University will be used to measure the fabricated filter responses. E5062A provides reliable basic S-parameter measurements with easy-to-use features. It has an operating frequency of 300kHz to 3GHz, supports both 50ohms and 75ohms test port impedances and have an output frequency resolution of 1Hz. A snapshot of the Agilent Network Analyzer E5062A is shown below.

Figure 37: Agilent Network Analyzer E5062A The following table illustrates some of the measurement capabilities of E5062A [27].

Table 11: Measurement capabilities of E5062A

4.5Selection of SMA Connector SMA, which is an acronym for Sub-Miniature version A, has a characteristic impedance of 50  and provides excellent electrical performance from DC to 18 GHz. They are also compact in size and have outstanding durability. A snapshot of various SMA connectors such as Semi-Rigid Cable Connector, Flexible Cable Connector, Printed Circuit Board and Surface Mount Connector is shown below.

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Figure 38: Various SMA connectors SMA 1227, PCB Edged Mount Connector has been chosen for this project. Details of SMA connectors are available at Appendix D. The selection of the SMA connector is dependent on the design layer-out or structure.

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5. DEVELOPMENTS OF BANDPASS FILTER DESIGN 5.1Proposed Specifications of Initial LTCC Filter Design In order to kick start the development of the initial multilayer LTCC bandpass filter design, a realistic design goal will be proposed. The following table illustrates the proposed specifications of the initial LTCC filter design.

Table 12: Proposed specifications of initial LTCC filter design

5.2Proposed Configuration of Initial LTCC Filter Design Once the specifications have been set, the next stage would be to define the configuration of the initial LTCC filter design layout. The proposed design layout architecture would consist of five conductive micro-strip layers separated by four layers of DuPont 951 substrate. The first and fifth layers are designed to be ground plane. The second microstrip layer is designed to contain a Parallel-Coupled resonator, likewise for the third micro-strip layer. The fourth micro-strip layer is designed to contain both a left bend resonator and a right bend resonator. A cross-sectional view as well as the layout architecture of the initial LTCC filter design is shown below.

Figure 39: Cross-sectional view of initial LTCC filter design

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Figure 40: Layout architecture of initial LTCC filter design

5.3Initial LTCC Filter Design and Simulation using Agilent ADS Software Defining Substrate Properties and Simulation Control Environment within Agilent ADS Software Before the proposed filter can designed using Agilent ADS Software, substrate properties have to be first defined. The parameters to be defined for substrate properties are dielectric constant of 7.84, loss tangent of 0.005 and thickness of 100µm. To optimize the performance of the proposed filter, manipulation of the distance of the gap between resonators to tune the capacitance value and varying the overlapping area between resonators to tune the coupling strength can be done. Parameters such as individual substrate height and dimensions of the resonators can also be fine-tuned. The resultant overall dimensions of the initial LTCC filter design after fine-tuning are 1090µm x 1050µm x 630µm. The height of individual substrate layers have been tuned to S1=0.26mm, S2=S3=0.045mm and S4=0.28mm.

Figure 41: Defining substrate properties for initial LTCC filter design

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Once the proposed filter design is completed, simulation control parameters have to be defined in order to perform simulation. The simulator is set up to perform adaptive sweep between 0GHz - 10GHz with 999 sample points as shown in the following figure.

Figure 42: Setting up of simulation control environment for initial LTCC filter design Defining Port Parameters within Agilent ADS Software In order to simulate the use of 50  SMA connectors, both input and output ports of the filter must be set to 50  in the Agilent ADS Software “Port Properties Editor” as shown in the figure below.

Figure 43: Defining port properties for initial LTCC filter design

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5.4Simulation Results of Initial LTCC Filter Design The simulation results obtained from Agilent ADS Software shows an insertion loss of 0.006dB, a return loss of -31.588dB and a bandwidth of 2.049GHz at the centre frequency of 2.535GHz. By comparing the obtained simulated results with the specifications in Table 12, this initial LTCC filter design has failed to achieve the return loss requirements of < -35dB and will have to be improved.

Figure 44: Layout structure of initial LTCC filter design

Figure 45: S11 response of initial LTCC filter design

Figure 46: S21 response of initial LTCC filter design

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5.5Enhanced LTCC Filter Design In order to improve the insertion loss and return loss, the enhanced LTCC filter design has an additional parallel micro-strip at the fourth layer between the left bend and right bend resonators. The physical lengths of the resonators were also increased in order to obtain a centre frequency as close as possible to the proposed centre frequency of 2.5GHz. Please refer to Appendix E for more details of enhancing the initial LTCC filter design. A cross-sectional view as well as the layout architecture of the enhanced LTCC filter design is shown below. The dimensions of the enhanced LTCC filter design as well as the height of individual substrate layers remains unchanged from the initial LTCC filter design.

Figure 47: Cross-sectional view of enhanced LTCC filter design

Figure 48: Layout architecture of enhanced LTCC filter design

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5.6Simulation Results of Enhanced LTCC Filter Design The simulation results obtained from Agilent ADS Software shows that all specifications defined in Table 12 have been met. Improvements can be seen for insertion loss from 0.006dB to -0.002dB and for return loss from -31.588dB to -39.148dB. The centre frequency has also been improved from 2.535GHz to 2.513GHz with a bandwidth of 1.875GHz.

Figure 49: Layout structure of enhanced LTCC filter design

Figure 50: S11 response of enhanced LTCC filter design

Figure 51: S21 response of enhanced LTCC filter design

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5.7Modelling of Filter Design using FR4-86 Substrate Due to the high cost involved with using DuPont 951 substrate for fabrication as well as the complexity involved in fabrication of miniaturized components, the enhanced LTCC filter design will be re-modelled to use FR4-86 substrate instead while the overall dimensions will also be enlarged. The original design specifications will also have to be reviewed due to the poorer performance of FR4-86 substrate. Please refer to Table 6 and Table 7 for more detailed information of substrate performances. The following table illustrates the proposed specifications of the re-modelled initial filter design (FR4-86 substrate).

Table 13: Proposed specifications of re-modelled initial filter design (FR4-86 substrate) The re-modelled initial filter design layout architecture would still consist of five conductive micro-strip layers separated by four layers of FR4-86 substrate. There are no changes in the layout except for the fourth layer. There, the left bend and right bend resonators have evolved to look like triangles instead and will help to improve return loss. Please refer to Appendix F for more details of re-modelling the filter design using FR4-86 substrate. A cross-sectional view as well as the layout architecture of the re-modelled initial filter design (FR4-86 substrate) is shown below.

Figure 52: Cross-sectional view of re-modelled initial filter design (FR4-86 substrate)

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Figure 53: Layout architecture of re-modelled initial filter design (FR4-86 substrate)

5.8Re-modelled Initial Filter Design (FR4-86 Substrate) and Simulation using Agilent ADS Software Defining Substrate Properties and Simulation Control Environment within Agilent ADS Software Before the proposed filter can designed using Agilent ADS Software, substrate properties have to be defined once again. The parameters to be defined for substrate properties are dielectric constant of 4.7, loss tangent of 0.016 and thickness of 1600µm. The resultant overall dimensions of the re-modelled initial filter design (FR4-86 substrate) after fine-tuning are 16000µm x 10500µm x 6400µm. The height of the individual substrate layers have also increased to S1=S2=S3=S4=1600µm.

Figure 54: Defining substrate properties for re-modelled initial filter design (FR4-86 substrate)

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Once the proposed filter design has been completed, simulation control parameters will be defined once again to perform simulation. The simulator is set up to perform adaptive sweep between 0GHz - 3GHz with 999 sample points as shown in the following figure.

Figure 55: Setting up of simulation control environment for re-modelled initial filter design (FR4-86 substrate) Defining Port Parameters within Agilent ADS Software Both input and output ports of the filter must be set to 50  in the Agilent ADS Software “Port Properties Editor” in order to simulate the use of 50  SMA connectors.

Figure 56: Defining port properties for re-modelled initial filter design (FR4-86 substrate) 62 | P a g e

5.9Simulation Results of Re-modelled Initial Filter Design (FR4-86 Substrate) The simulation results obtained from Agilent ADS Software shows an insertion loss of 0.012dB, a return loss of -47.642dB and a bandwidth of 717MHz at the centre frequency of 396.7MHz. Even though return loss has improved from the previous LTCC filter design, the overall performance of the re-modelled initial filter design has reduced substantially due to the quality of substrate used (FR4-86). Centre frequency will have to be improved drastically which will involve more design changes.

Figure 57: Layout structure of re-modelled initial filter design (FR4-86 substrate)

Figure 58: S11 response of re-modelled initial filter design (FR4-86 substrate)

Figure 59: S21 response of re-modelled initial filter design (FR4-86 substrate)

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5.10 Enhanced Re-modelled Filter Design using FR4-86 Substrate In order to improve the centre frequency, the enhanced re-modelled filter design (FR4-86 substrate) will have a micro-strip connecting the left and right “triangle” resonators at the fourth layer instead of the additional parallel micro-strip. In order to accommodate the assembly of the SMA connectors, the overall dimensions of the enhanced re-modelled filter design (FR4-86 substrate) will also be further enlarged to 43000µm x 18000µm x 6400µm. The height of the individual substrate layers have remained unchanged from before, S1=S2=S3=S4=1600µm. Increases in overall dimensions have also helped to improve return loss which had been affected by the changes in filter design. Please refer to Appendix G for more details of enhancing the re-modelled initial filter design. A cross-sectional view as well as the layout architecture of the enhanced re-modelled filter design (FR4-86 substrate) is shown below.

Figure 60: Cross-sectional view of enhanced re-modelled filter design (FR4-86 substrate)

Figure 61: Layout architecture of enhanced re-modelled filter design (FR4-86 substrate) 64 | P a g e

5.11 Simulation Results of Enhanced Re-modelled Filter Design using FR4-86 Substrate The simulation results obtained from Agilent ADS Software shows an insertion loss of 0.401dB, a return loss of -39.037dB and a bandwidth of 186MHz at an improved centre frequency of 1.458GHz. All specifications defined in Table 13 have been achieved. This filter design has produced the best possible result obtainable from using FR4-86 substrate. Critical dimensions of the filter prototype will be illustrated in the next section. The next step forward would be fabrication and assembly of filter prototype in order to measure and validate the actual filter response.

Figure 62: Layout structure of enhanced re-modelled filter design (FR4-86 substrate)

Figure 63: S11 and S21 responses of enhanced re-modelled filter design (FR4-86 substrate)

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5.12 Critical Dimensions of Finalized Filter Design using FR4-86 Substrate The critical dimensions of the individual micro-strip layers are presented below.

Figure 64: Overall dimensions of finalized filter design using FR4-86 substrate; same dimensions to be used for first and fifth layer (ground plane)

Figure 65: Critical dimensions of second layer (Parallel-Coupled resonator)

Figure 66: Critical dimensions of third layer (Parallel-Coupled resonator)

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Figure 67: Critical dimensions of fourth layer (left and right “triangle” resonators connected by micro-strip)

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6. FABRICATION AND ASSEMBLY OF FILTER PROTOTYPE The finalized design of the multilayer bandpass filter prototype layout is shown in the figure below.

Figure 68: Multilayer bandpass filter prototype layout The following figures illustrate the different conductor layers of the multilayer bandpass filter prototype.

Figure 69: “Cond” layer

Figure 70: “Cond2” layer

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Figure 71: "Resi" layer

Figure 72: “Diel” layer

6.1Exporting Gerber Files Once the design of filter prototype has been finalized in Agilent ADS software, the required files in Gerber format needs to be exported in order to fabricate the filter prototype. The following steps were taken in exporting the Gerber files: Step 1 Delete the Input / Output ports from the “resi” layer Removed Input / Output ports

Figure 73: “Resi” layer without Input / Output ports 69 | P a g e

Step 2 Create a border for each conductor layer

Figure 74: "Cond" layer with border

Figure 75: "Cond2" layer with border

Figure 76: "Resi" layer with border

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Figure 77: "Diel" layer with border Step 3 Setting up and exporting the Gerber files The following settings were used in exporting the Gerber files: Output Unit: mm Number Format: 2:4 In order for the fabricated filter prototype to have the right dimensions, these settings are made known to the fabrication vendor. This will also ensure that the layout of each resonator position is aligned. The figure below shows the “Export Gerber Options” window with the above settings used.

Figure 78: "Export Gerber Options" window

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The figures below illustrate the steps of exporting Gerber files.

Figure 79: Step-by-step guide in exporting Gerber files

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6.2Assembly of Fabricated Filter Prototype The designed filter is fabricated on FR4-86 board using HASL finishing. The figure below shows a comparison between the layouts of each conductor layer of the designed filter in Agilent ADS Software, with the actual fabricated layers using HASL finishing.

(a)

(b)

Figure 80: Comparison between a) Conductor layers of the designed filter in Agilent ADS Software; b) Actual fabricated layers using HASL finishing

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The following table illustrates the steps taken to assemble the individual layers of the filter prototype together to form the designed multilayer bandpass filter. Step 1: Place the fabricated PWBs on a softwooden board and use pins to secure its position.

Step 2: The required slots for inserting the SMA Connector s are removed using AEMG PR2228/S4 PCB Routing Machine.

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Step 3: The PWBs are further refined by filing the edges with sandpaper.

Step 4: The SMA Connector s are soldered onto the PWBs.

Step 5: Lastly, the assembled multilayer bandpass filter is inspected to ensure no “cold solder joints”. Table 14: Step-by-step guide in assembling the filter prototype

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7. COMPARISON BETWEEN MEASURED AND SIMULATED RESULTS 7.1Measurement of Filter Responses The following equipment and accessories were used in the measurement of the designed filter response at SIM University. 

Agilent Network Analyzer E5062A

Figure 81: Agilent Network Analyzer E5062A 

2 x BNC adaptors with 50  termination

Figure 82: 2 x BNC adaptors with 50  termination 

2 x BNC to SMA cables

Figure 83: 2 x BNC to SMA cables

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The following steps illustrate the filter response measurements. Step 1 Connect the BNC adaptors with 50  termination to Port 1 and Port 2 of the Agilent Network Analyzer E5062A. Step 2 Connect the BNC end of cable to the BNC adaptor and the SMA end of the cable to the SMA connector on the fabricated filter prototype. Step 3 Switch on the Agilent Network Analyzer E5062A and tune it to sweep from 1GHz to 2GHz. Step 4 Obtain the filter responses such as magnitude of S11 and S21, centre frequency and bandwidth by using “measurement” and “marker” functions. Step 5 Screen capture and save the results of the filter response.

Figure 84: Connection of BNC end of cable to BNC adaptors on Agilent Network Analyzer E5062A

Figure 85: Connection of SMA end of cable to SMA connectors on fabricated filter prototype

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7.2Comparison Analysis between Measured and Simulated Results The following figures illustrate the measured filter responses as compared to the simulated filter responses from Agilent ADS Software.

Figure 86: S11 response of fabricated filter prototype

Figure 87: S21 response of fabricated filter prototype

Figure 88: Simulated filter responses from Agilent ADS Software

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The filter response measured from fabricated filter prototype is reasonably good. The fabricated filter prototype is measured as having an insertion loss of 9.0126dB, a return loss of 38.129dB and a bandwidth of 132MHz at the centre frequency of 1.351GHz while the simulation produced results of an insertion loss of 0.401dB, a return loss of 39.037dB and a bandwidth of 186MHz at the centre frequency of 1.458GHz. The table below summarizes the comparison.

Table 15: Comparison table between measured vs. simulated results The additional losses in insertion loss and return loss as well as the frequency shift for both bandwidth and centre frequency observed in the measured filter response could be due to a slight misalignment of the different layers. These misalignments will result in a decrease in overall capacitance reactive or an increase in the inductance reactive hence causing variances in the measured results. Upon closer examination of the fabricated filter prototype, tiny air gaps can be seen between the different layers. These air gaps allow air to pass through thus creating an inconsistent dielectric constant between the different layers which further contributes to additional losses and frequency shift in bandwidth and centre frequency.

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8. CONCLUSION From the results obtained from the previous chapters, it can be concluded that the objective of designing a multilayer LTCC bandpass filter can be realized with the implementation of multilayer resonator configuration on micro-strip filter. However, factors such as ease of fabrication, ease of assembly and complexity of design have to be taken into consideration as they can affect filter response. From the simulation results, it can be shown that by changing the design of the resonators, better performances can be attained. However, the fact that parameters such as substrate height, distance of the gap between resonators, overlapping area between resonators are variable, only served to increase the difficulties of achieving the desired results. The measured filter response was not able to match up to the simulated filter response and an analysis was conducted to investigate the possible reasons for the mismatch. It was found that the likely causes were slight misalignment of the different layers as well as tiny air gaps existed between the different layers. Solutions to fix the possible highlighted problems will be suggested for future implementation.

8.1Suggestion for Future Work Even though this project has been a success, on hindsight, there are still some areas which can be further improved to achieve better filter responses. Some suggestions to achieving better filter responses as follows: 

 

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Ensure proper alignment of the different conductor layers and utilize commercially available multilayer lamination process. By doing so, the different layers are fused together by high pressure and heat, hence preventing air gaps from forming. Frequency shift and additional losses due to misalignment and air gaps issues are thus resolved. Usage of a metal enclosure will produce a better and more realistic filter response as it reduces the effect of radiation loss. However, the cost of the project will also increase. Other than using FR4-86, usage of other materials with different gains and insertion loss or adopting VIA-punching can also be explored but the cost of the project might possibly increase.

9. CRITICAL REVIEWS AND REFLECTIONS This has been an interesting project for me as I had experienced for the first time, the entire process of producing a micro-strip filter, from the design and simulation phase to the fabrication and test / measurement phase. Coming to grips with the theory of micro-strip filter and related topics was only the first tiny step taken in this project. The next step forward was to list down the requirements of the project which then leads to filter design and simulation phase. This phase involves not only understanding thoroughly the requirements of the filter design but also include a significant amount of work in familiarizing with the software simulator tool in order to design and perform simulation seamlessly. This phase had to be repeated several times until the proposed filter design was deemed to have fulfilled all requirements. The project started fairly well with constant discussions taking place with the Project Supervisor on the objectives and vision of the project. There was a need to strike a balance, to propose an exciting yet achievable scope for the project. However, the progress of the project stalled when I reached the filter design phase due to the fact that I was weak in this area. Everything was a mess and new problems appeared almost on a daily basis. It was definitely not an enjoyable experience being a beginner in filter design. There was a constant need to refer to tutorials and reference materials for help which was really a vexing experience. The completion of this project after months of hard work has enriched me in several ways. The struggles during the filter design and fabrication phases helped me gained valuable knowledge. The project also made me more disciplined and independent as I had to work autonomously in order to deliver results. Project management skills were also put to test during this period. I have now fully understood the importance and meaning of having a well thought-out plan. Having a plan which is good, clear and concise will help to reduce a lot of unnecessary re-work. And lastly, good time management skills was also essential as I have a full time job which was very taxing as it required me to travel frequently overseas for on-site assistance. Thanks to the full support of my colleagues, I was able to reduce my work-related travels to spend more time on the project.

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Sherry Goodell, “Hot Air Leveling”, retrieved from http://www.goldphoenixpcb.biz/pdf/Chapter_30-HAL.pdf

[23]

RF network analyzer basics tutorial, retrieved from http://www.radio-electronics.com/info/t_and_m/rf-network-analyzer/analyserbasics-tutorial.php

[24]

Reinhard kulke, Matthias Rittweger, et al. “LTCC-Multilayer ceramic for Wireless and Sensor Applications,” LTCC – An Introduction and Overview, IMST GmbH, Dec 2001, retrieved from www.ltcc.de/downloads/rd/pub/10-doc-plus-engl-2001.pdf

[25]

Ansoft HFSS, retrieved from http://www.ansoft.com/products/hf/hfss

[26]

Lead-Free Printed Circuit Board Surface Finishes, retrieved from http://www.trianglecircuits.com/lead-free-finishes.html

[27]

Agilent ENA-L RF Network Analyzers, retrieved from http://cp.literature.agilent.com/litweb/pdf/5989-0018EN.pdf

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[28]

Yoshihiko Imanaka, “Multilayered Low Temperature Co-fired Ceramics (LTCC) Technology http://books.google.com.sg/books?hl=en&lr=&id=uU2rnznM2kC&oi=fnd&pg=PR11&dq=history+of+ltcc+technology&ots=loxSOpSu7 Q&sig=jJckqJ-Z4uFZOkwWHIcMZkyE6Wo#v=onepage&q&f=false

[29]

“IMST homepage - LTCC process” retrieved from http://www.ltcc.de/en/whatis_pro.php

[30]

“Wikipedia – Microwave” retrieved from http://en.wikipedia.org/wiki/Microwave

[31]

K.C. Gupta, Ramesh Garg, Inder Bahl, Prakash Bhartia, “Microstrip Lines and Slotlines” Second Edition, Artech House, Inc., 1996

[32]

Daniel M. Dobkin, “The RF in RFID – Passive UHF RFID in Practice”, Elsevier Inc., 2008

[33]

Ahmad A. Sulaiman, Mohd H. Mokhtar, Mohd H. Jusoh, Nor H. Baba, Rabi’atun A. Awang, Mohd F. Ain “Simple Multilayer Hairpin Bandpass Filter” retrieved from http://www.eurojournals.com/ejsr_42_4_07.pdf

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11. APPENDIX A Appendix A shows the steps taken to compute the Score Chart (Table 3.3) with the given data. Supplier

Substrate

Tan(  )

r

Arlon

AR 600 AR 1000 RF-60 CER-10 951AX-Au 951AX-Ag A6M, Ag FR4-86

0.35 0.35 0.28 0.35 0.5 0.2 0.2 2.7

6 10 6.15 10 7.84 7.84 5.9 4.7

Taconic DuPont Ferro Nan Ya

TCE ppm/K 12 14 12 14 5.8 5.8 8 18

Thickness

m

635 635 635 635 100 100 185 1600

Relative Price 6.1 4.8 1.1 1.8 1.5 1.0 0.6 0.2

Step 1: Finding the interval value From the table above, each property of the substrate is divided into 10 equal intervals by the following equation:

Where, Vinterval: is the interval value between each range Vmax: is the highest value of the given properties Vmin: is the lowest value of the given properties Example: Finding the interval value of Tan (  )

Step 2: Finding the Inter Range The 10 equal Interval Range can be computed as follows: Interval Range (i) 1 2 3 4 5 6 7 8 9 10

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Lower Value Li Vmin Ui-1 Ui-1 Ui-1 Ui-1 Ui-1 Ui-1 Ui-1 Ui-1 Ui-1

Upper Value Ui Vmin + Vinterval Ui-1 + Vinterval Ui-1 + Vinterval Ui-1 + Vinterval Ui-1 + Vinterval Ui-1 + Vinterval Ui-1 + Vinterval Ui-1 + Vinterval Ui-1 + Vinterval Ui-1 + Vinterval

Example: Finding the Interval Range of Tan ( ) Interval Range (i) 1 2 3 4 5 6 7 8 9 10

Lower Value Li 0.2 0.45 0.7 0.95 1.2 1.45 1.7 1.95 2.2 2.45

Upper Value Ui 0.2+0.25=0.45 0.45+0.25=0.7 0.7+0.25=0.95 0.95+0.25=1.2 1.2+0.25=1.45 1.45+0.25=1.7 1.7+0.25=1.95 1.95 +0.25=2.2 2.2+0.25=2.45 2.45+0.25=2.7

Step 3: Assigning a score to each substrate for a given property A score of 1 to 10 is given to each substrate based on where the property value of that substrate falls under in the Interval Range Table. (Best: 10, Worst is: 1) Example: Assigning Score to each substrate based on Tan (  ) Interval Range (i) 1 2 3 4 5 6 7 8 9 10

Lower Value Li 0.2 0.45 0.7 0.95 1.2 1.45 1.7 1.95 2.2 2.45 Arlon Taconic DuPont Ferro Nan Ya

Upper Value Ui 0.45 0.7 0.95 1.2 1.45 1.7 1.95 2.2 2.45 2.7

AR 600 AR 1000 RF-60 CER-10 951AX-Au 951AX-Ag A6M, Ag FR4-86

0.35 0.35 0.28 0.35 0.5 0.2 0.2 2.7

SCORE 10 9 8 7 6 5 4 3 2 1 10 10 10 10 9 10 10 1

Step 4: Summing up the total Score Step 1 to 3 is repeated for all the properties of each substrate. The final step will be to sum up the total score for each substrate to determine the most desired substrate material to be used. The result is shown in Table 3.3.

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12. APPENDIX B

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13. APPENDIX C

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14. APPENDIX D

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15. APPENDIX E Rejected Bandpass Filters from LTCC Filter Designs Index No. 1

2

3

4

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Filter design Layout

S11 and S21 Response

5

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16. APPENDIX F Rejected Bandpass Filters from Enhanced LTCC Filter Design to Remodelled Initial Filter Design (FR4-86 Substrate) Index No. 1

2

3

4

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Filter design Layout

S11 and S21 Response

5

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17. APPENDIX G Rejected Bandpass Filters from Enhanced Re-modelled Filter Design using FR4-86 Substrate Index No. 1

2

4

5

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Filter design Layout

S11 and S21 Response

6

7

8

9

10

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18. APPENDIX H CAPSTONE Project Meeting Report 1 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

10 Other comment/Areas to improve 11 Reference materials

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12 February 2011 12:00pm – 14.00pm 2 hours UniSIM HQ 5.17B Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS / Dr. Lum Kum Meng NIL 1. Discussion of project scope. 2. Highlight of project programs expectation. 3. Highlight of filter design specification (IEEE paper review) 4. Show understanding for the usage for the ADS software. 5. Highlight of the first design of the project. 6. Objective of next meeting, presentation understand of the first filter design. 1. Submit the meeting log 2. Know how to use ADS software. 3. Preparation of proposal. (10%) 1. Next meeting will be held on 26 February at UniSIM HQ 5.17B 1. Ishizaki, T., T. Uwano, and H. Miyake, “An extend configuration of a stepped impedance comb-line filter,” IEICE Trans, Electron., E79-C, 671-678, 1996 2. Sim, S. H., C. Y. Kang, S. J Yoon, Y. J. Yoon, and H. J. Kim, “ Broadband multilayer ceramic chip antenna for handsets,” Electron. Lett., Vol. 38, 205207, 2002 3. Lew, D. W., J. S. Park, D. Ahn, N. K. Kang, C. S Yoo, and J. B. Lim, “ A design of the ceramic chip balun using the multilayer configuration,” IEEE Trans. Microwave Theory Tech., Vol. 49, 220224, 2001. 4. Dernovsek, O., A. Naeini, G. Preu, W.

12 How did you progress so far? (10 Excellent, 1 Poor)

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Wersing, M. Eberstein b, and W. A. Schiller, “ LTCC glass-ceramic composites for microwave application,” Journal of the European Ceramic Society, Vol. 21, 1693-169, 2001. 5. Leung, W. Y., K. Keung, M. Cheng, and K. L. Wu, “ Multilayer LTCC bandpass filter design with enhanced stopband characteristics,” IEEE Microwave and Wireless Components letters, Vol. 12, N0. 7, 240-242, 2002 6. ADS website 7. IEEE-MTT website NIL

CAPSTONE Project Meeting Report 2 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

26 February 2011 12:00pm – 14.00pm 2 hours UniSIM HQ 5.17B Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS / Dr. Lum Kum Meng NIL 1

Demonstration of ADS usage and function. 2. Expectation of proposal content. 3. Brief highlight of the first filter design. 1. Submit the meeting log 2. Get familiar with ADS software 3. Preparation of proposal. (70%)

10 Other comment/Areas to improve

1. Next meeting will be held on 26 February at UniSIM HQ 5.17B 2. Commencement of the first filter design using ADS filter momentum. 3. Presentation of first filter design working mechanism

11 Reference materials

1. Ishizaki, T., T. Uwano, and H. Miyake, “An extend configuration of a stepped impedance comb-line filter,” IEICE Trans, Electron., E79-C, 671-678, 1996 2. Sim, S. H., C. Y. Kang, S. J Yoon, Y. J. Yoon, and H. J. Kim, “ Broadband multilayer ceramic chip antenna for handsets,” Electron. Lett., Vol. 38, 205207, 2002 3. Lew, D. W., J. S. Park, D. Ahn, N. K. Kang, C. S Yoo, and J. B. Lim, “ A design of the ceramic chip balun using the multilayer configuration,” IEEE Trans. Microwave Theory Tech., Vol. 49, 220224, 2001. 4. Dernovsek, O., A. Naeini, G. Preu, W. Wersing, M. Eberstein b, and W. A. Schiller, “ LTCC glass-ceramic composites for microwave application,”

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12 How did you progress so far? (10 Excellent, 1 Poor)

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Journal of the European Ceramic Society, Vol. 21, 1693-169, 2001. 5. Leung, W. Y., K. Keung, M. Cheng, and K. L. Wu, “ Multilayer LTCC bandpass filter design with enhanced stopband characteristics,” IEEE Microwave and Wireless Components letters, Vol. 12, N0. 7, 240-242, 2002 6. ADS website 7. IEEE-MTT website 2

CAPSTONE Project Meeting Report 3 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

12 March 2011 12:00pm – 14.00pm 2 hours UniSIM HQ 5.17B Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS Dr. Lum Kum Meng NIL 1. Verification of first filter design performance (ADS Simulation) 2. Discussion on how to improved filter response 3. Discussion on the key objective for the next meeting a. Presentation on the improvement on the improvement on the filter b. Research and understand on design of filter on the microstrip

Action items/ Targets to achieve

1. Submit the meeting log 2. Try to complete drawing of the first filter design. (50%)

10 Other comment/Areas to improve

1. Next meeting will be held on 26 March at UniSIM HQ 5.17B 2. Commencement of the first filter design using ADS filter momentum.

11 Reference materials

1. Ishizaki, T., T. Uwano, and H. Miyake, “An extend configuration of a stepped impedance comb-line filter,” IEICE Trans, Electron., E79-C, 671-678, 1996 2. Sim, S. H., C. Y. Kang, S. J Yoon, Y. J. Yoon, and H. J. Kim, “ Broadband multilayer ceramic chip antenna for handsets,” Electron. Lett., Vol. 38, 205207, 2002 3. Lew, D. W., J. S. Park, D. Ahn, N. K. Kang, C. S Yoo, and J. B. Lim, “ A design of the ceramic chip balun using the multilayer configuration,” IEEE Trans. Microwave Theory Tech., Vol. 49, 220224, 2001.

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12 How did you progress so far? (10 Excellent, 1 Poor)

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4. Dernovsek, O., A. Naeini, G. Preu, W. Wersing, M. Eberstein b, and W. A. Schiller, “ LTCC glass-ceramic composites for microwave application,” Journal of the European Ceramic Society, Vol. 21, 1693-169, 2001. 5. Leung, W. Y., K. Keung, M. Cheng, and K. L. Wu, “ Multilayer LTCC bandpass filter design with enhanced stopband characteristics,” IEEE Microwave and Wireless Components letters, Vol. 12, N0. 7, 240-242, 2002 6. Sim, S. H., C. Y. Kang, and J. W. Choi, “A compact lumped-element lowpass filter using temperature co-fired ceramic technology,” Vol. 23, 2717-2720, 2003 7. Zhao, Y. J. and Y. Z. Yin, “An efficient deign method of LTCC filters with aggressive space mapping technique,” Microwave and optical technology Letters, Vol. 41, No. 1, 24-28, 2004 8. IEEE-MTT website 2

CAPSTONE Project Meeting Report 4 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

10 Other comment/Areas to improve 11 Reference materials

12 How did you progress so far? (10 Excellent, 1 Poor)

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26 March 2011 12:00pm – 14.00pm 2 hours UniSIM HQ 5.17B Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS Dr. Lum Kum Meng NIL 1. Verification of first filter design performance (ADS Simulation) 2. Discussion on next improved filter metrology 3. Discussion on objective for the next meeting 1. Complete drawing of the first filter design layout 2. Achieve ADS simulation results on the first filter 3. Submit the meeting log 1. Next meeting will be held on 16 April at UniSIM HQ 5.17B 1. Jia-Sheng Hong, M.J. Lan Caster, “Combline Filter,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 2. Jia-Sheng Hong, M.J. Lan Caster, “Lumped Inductors and Capacitors,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 3. K.C. Gupta, Ramesh Garg, Inder Bahl, Prakash Bhartia , “ Microstrip Lines and Slotlines” Second Edition, Artech House, Inc., 1996 4. IEEE-MTT website 3

CAPSTONE Project Meeting Report 5 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

10 Other comment/Areas to improve 11 Reference materials

12 How did you progress so far? (10 Excellent, 1 Poor)

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16 April 2011 9:00am – 11.00am 2 hours UniSIM HQ 5.17B Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS Dr. Lum Kum Meng NIL 1. Modification on the first filter design, change the demotion of resonators try to improve the performance 2. Discussion on objective for the next meeting 1. Improve the first design result. (20%) 2. Try to get ready for fabrication 3. Submit the meeting log 1. Next meeting will be held on 30April at UniSIM HQ 5.17B 1. Jia-Sheng Hong, M.J. Lan Caster, “Combline Filter,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 2. Jia-Sheng Hong, M.J. Lan Caster, “Lumped Inductors and Capacitors,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 3. K.C. Gupta, Ramesh Garg, Inder Bahl, Prakash Bhartia , “ Microstrip Lines and Slotlines” Second Edition, Artech House, Inc., 1996 4. IEEE-MTT website 5

CAPSTONE Project Meeting Report 6 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

10 Other comment/Areas to improve 11 Reference materials

12 How did you progress so far? (10 Excellent, 1 Poor)

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30 April 2011 9:00am – 11.00am 2 hours UniSIM HQ 5.17B Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS / Dr. Lum Kum Meng NIL 1. Verification changes on the first filter design performance (ADS Simulation) 2. Compare filter designs and discuss improvement to be made in the designs 3. Discussion on next improved filter design layout 4. Discussion on objective for the next meeting 5. Presentation on the improvement of the filter 6. Research and understand on design of filter on the bandpass filter parameters 1. 2. 3. 1.

Improve the first design result (50%) Try to get ready for fabrication Submit the meeting log Next meeting will be held on 30April at UniSIM HQ 5.17B 1. Jia-Sheng Hong, M.J. Lan Caster, “Combline Filter,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 2. Jia-Sheng Hong, M.J. Lan Caster, “Lumped Inductors and Capacitors,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 3. K.C. Gupta, Ramesh Garg, Inder Bahl, Prakash Bhartia , “ Microstrip Lines and Slotlines” Second Edition, Artech House, Inc., 1996 IEEE-MTT website 5

CAPSTONE Project Meeting Report 7 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

10 Other comment/Areas to improve 11 Reference materials

12 How did you progress so far? (10 Excellent, 1 Poor)

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01 June 2011 7:30pm – 9:30pm 2 hours Serangoon Communicate Center L1 Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS / Dr. Lum Kum Meng NIL 1. Finalize the first filter design 2. Discuss with supervisor on the second filter design:  The second filter center frequency  Targeted insertion loss and return loss 1. Determine the key parameter of the second filter design. 2. Star to draft the final year project report, need to get at lease (5%) complete before next meeting. 3. Submit the meeting log 1. Next meeting will be held on 22th June at Serangoon Communicate center L1. 1. Jia-Sheng Hong, M.J. Lan Caster, “Combline Filter,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 2. Jia-Sheng Hong, M.J. Lan Caster, “Lumped Inductors and Capacitors,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 3. K.C. Gupta, Ramesh Garg, Inder Bahl, Prakash Bhartia , “ Microstrip Lines and Slotlines” Second Edition, Artech House, Inc., 1996 4. IEEE-MTT website 5

CAPSTONE Project Meeting Report 8 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

10 Other comment/Areas to improve 11 Reference materials

12 How did you progress so far? (10 Excellent, 1 Poor)

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22 June 2011 7:30pm – 9:30pm 2 hours Serangoon Communicate Center L1 Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS / Dr. Lum Kum Meng NIL 1. Supervisor checked and advised on the second filter design, need to improve the S11 and S21 response of the filter design. 2. Supervisor has provided some contact of the fabrication vendor. 3. Discuss with supervisor with the main concept of the final year report. 1. Determine the key parameter of the second filter design. 2. Carry on to draft the final year project report, need to get at lease (10%) complete before next meeting. 3. Submit the meeting log 1. Next meeting will be held on 6th July at Serangoon Communicate center L1. 1. Jia-Sheng Hong, M.J. Lan Caster, “Combline Filter,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 2. Jia-Sheng Hong, M.J. Lan Caster, “Lumped Inductors and Capacitors,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 3. K.C. Gupta, Ramesh Garg, Inder Bahl, Prakash Bhartia , “ Microstrip Lines and Slotlines” Second Edition, Artech House, Inc., 1996 4. IEEE-MTT website 5

CAPSTONE Project Meeting Report 9 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

10 Other comment/Areas to improve 11 Reference materials

12 How did you progress so far? (10 Excellent, 1 Poor)

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6 July 2011 7:30pm – 9:30pm 2 hours Serangoon Communicate Center L1 Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS Dr. Lum Kum Meng NIL 1. Present modified second filter design to supervisor, due to insertion loss still too high, filter design still need to be modified. 2. Discuss the fabrication vendor details with supervisor. 3. Discuss final report Chapter 1 & 2 details with supervisor. 1. Improve the second filter design. 2. Carry on to draft the final year project report, need to complete Chapter1 and 2 before next meeting. 3. Submit the meeting log 1. Next meeting will be held on 6th July at Serangoon Communicate center L1. 1. Jia-Sheng Hong, M.J. Lan Caster, “Combline Filter,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 2. Jia-Sheng Hong, M.J. Lan Caster, “Lumped Inductors and Capacitors,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 3. K.C. Gupta, Ramesh Garg, Inder Bahl, Prakash Bhartia , “ Microstrip Lines and Slotlines” Second Edition, Artech House, Inc., 1996 4. IEEE-MTT website 5

CAPSTONE Project Meeting Report 10 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

10 Other comment/Areas to improve 11 Reference materials

12 How did you progress so far? (10 Excellent, 1 Poor)

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20 July 2011 7:30pm – 9:30pm 2 hours Serangoon Communicate Center L1 Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS Dr. Lum Kum Meng NIL 1. Discuss the re-designed filter simulation result with supervisor, need to carry modify the design due the center frequency shifted. 2. Compare the price from different vendor and material. 3. Go through report Chapter 3 details with supervisor. 1. Get the filter design ready for fabrication by end of August. 2. Carry on draft the final year project report (30%). 3. Submit the meeting log 1. Next meeting will be held on 6th July at Serangoon Communicate center L1. 2. Jia-Sheng Hong, M.J. Lan Caster, “Combline Filter,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 3. Jia-Sheng Hong, M.J. Lan Caster, “Lumped Inductors and Capacitors,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 4. K.C. Gupta, Ramesh Garg, Inder Bahl, Prakash Bhartia , “ Microstrip Lines and Slotlines” Second Edition, Artech House, Inc., 1996 5. IEEE-MTT website 5

CAPSTONE Project Meeting Report 11 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

10 Other comment/Areas to improve 11 Reference materials

12 How did you progress so far? (10 Excellent, 1 Poor)

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12 August 2011 11:30am – 12:30pm 2 hours SIM Blk82 Lab5.01 Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS / Dr. Lum Kum Meng NIL 1. Finalized the filter design for fabrication 2. Demo on how to get gerber file by using ADS software for each filter layer. 3. Go through report Chapter 3 & 4 details with supervisor. 1. Get fabrication done before next meeting 2. Once fabrication finished need to start measurement by using Network Analyzer. 3. Carry on draft the final year project report (40%). 4. Submit the meeting log 1. Next meeting will be held on 25th September at SIM Blk82 Lab5.01 1. Jia-Sheng Hong, M.J. Lan Caster, “Combline Filter,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 2. Jia-Sheng Hong, M.J. Lan Caster, “Lumped Inductors and Capacitors,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 3. K.C. Gupta, Ramesh Garg, Inder Bahl, Prakash Bhartia , “ Microstrip Lines and Slotlines” Second Edition, Artech House, Inc., 1996 4. IEEE-MTT website 5

CAPSTONE Project Meeting Report 12 1 2 3 4 5 6

Date Time Duration Venue Student Name Project / Supervisor Name

7

Review of Previous Meeting and progress Minutes of current meeting

8

9

Action items/ Targets to achieve

10 Other comment/Areas to improve 11 Reference materials

12 How did you progress so far? (10 Excellent, 1 Poor)

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25 August 2011 11:30am – 12:30pm 2 hours SIM Blk82 Lab5.01 Guo Ling MULTILAYER LTCC BANDPASS FILTER FOR MICROWAVE APPLICATIONS / Dr. Lum Kum Meng NIL 1. Update supervisor the fabrication has been complete 2. Discuss the measured result with supervisor. 3. Supervisor has advised on the measured and simulated result and to record all finding in thesis. 1. Complete the simulation and measurement result comparison. 2. Carry on draft the final year project report, need to be complete before end of October. 3. Submit the meeting log 1. NIL 1. Jia-Sheng Hong, M.J. Lan Caster, “Combline Filter,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 2. Jia-Sheng Hong, M.J. Lan Caster, “Lumped Inductors and Capacitors,” Microstrip Filters for RF/Microwave Applications, New York: John Wiley & Sons Inc., 2001 3. K.C. Gupta, Ramesh Garg, Inder Bahl, Prakash Bhartia , “ Microstrip Lines and Slotlines” Second Edition, Artech House, Inc., 1996 4. IEEE-MTT website 5