# Square Loop Antenna

July 16, 2017 | Author: Lhaiszah Alagon | Category: Antenna (Radio), Polarization (Waves), Broadcast Engineering, Telecommunications, Electromagnetism

#### Short Description

square loop antenna design...

#### Description

SQUARE LOOP ANTENNA I.

Figure 1. Quad loops with a 1-λ circumference. The current distribution is shown for (A) horizontal and (B) vertical polarization.

A horizontally polarized quad-loop antenna (two stacked short dipoles) produces a wave angle that is dependent on the height of the loop. The low horizontally polarized quad (top at 0.3 λ) radiates most of its energy right at or near zenith angle (straight up). Figure 2 shows directivity patterns for a horizontally polarized loop. The horizontal pattern, Figure 2, is plotted for a takeoff angle of 30º. At low wave angles (20º to 45º), the horizontally polarized loop shows more frontto-side ratio (5 to 10 dB) than the vertically polarized rectangular loop.

Figure 2. Azimuth and elevation patterns of the horizontally polarized quad loop at low height (bottom wire 0.0375 λ above ground). At an elevation angle of 30°, the loop has a front-to-side ratio of approximately 8 dB.

Antenna

Parameter

Typical Values

Gain Bandwidth Frequency Limit

1 to 3 dB 10% (1.1:1) 50 MHz to 1 GHz

Polarization

Linear

Half-Power

(Horizontal) 100° x 360°

Elevation Pattern

Bandwidth Azimuth Pattern Figure 3. Square Loop Antenna Specification

II.

Computation

Figure 4. Square Loop Antenna Sample Calculator

The basic formula for determining the length of a full-wave wire Loop antenna is:

1005 ÷ freq (mHz) = Length (feet) Since closed loops are not subject to "end-effect" the calculated physical lengths with this formula are longer than corresponding dipole dimensions and are close to free space dimensions. Since the loop dimensions are larger than those of a half-wave dipole, the radiation efficiency is also higher.

III.

Output