Wideband Circularly Polarized Square Slot Array Fed by Slotted Waveguide for Satellite Communication

Abstract

A wideband circularly polarized (CP) slot array with high radiation efficiency is proposed. The cavity-backed square slots are designed to achieve wideband CP radiation with a unidirectional pattern. The slotted waveguide is adopted to feed the array with high efficiency. The square slot, cavity and feeding slot in the waveguide can be viewed as a radiating element. A CP slot array can be conveniently designed as traditional waveguide slot arrays, once the element admittance characteristic is determined. A 1-by-8 CP array operating at 12.5 GHz has been developed. Measured impedance bandwidth of 6.9%, axial-ratio (AR) bandwidth of 8.8% and a gain of 15.4 dBi have been achieved. This array can be conveniently expanded to a larger wideband CP array with a higher gain, which is preferred for the specific satellite communication applications.

Balanced circularly polarized square loop antenna under even-mode resonance

“…Now, let's further give comprehensive comparison with other typical uni-directional CP antennas in terms of the beam directions, front-to-back ratio, gain and 3 dB-AR beamwidth as Table 3. It is seen that the proposed antenna exhibits an axial-mode CP beam, and it is distinctive from most of the loop-like and slot-like antennas 22,[24][25][26][30][31][32][33][34]46,47 having normal-mode radiation patterns. The proposed CP antenna has simultaneously exhibited a wide 3dB AR beamwidth of 708, and a front-to-back ratio of 40 dB when using a planar reflector.…”

A Ka-Band Circular Polarized Waveguide Slot Antenna with a Cross Iris

“…For linear polarization antenna, if the polarizations of a transmitter and a receiver do not match each other, communication performance deteriorates. Meanwhile, circular polarization avoids polarization misalignment as the electric field rotates, and it reduces multipath fading with flexibility in orientation the angle between the transmitted receiver [4,5]. Therefore, circular polarized (CP) waveguide antennas in particular are widely used in modern satellite communication systems due to their advantages of enhancing the channel stability and reliability [6,7].…”