A Dual Circularly Polarized Array Antenna for Ka-Band Satellite Communications

This work presents a dual circularly polarized 8-by-8 array antenna using inbuilt polarizers for satellite communications. The design consists of five metal layers, including two feeding layers for the dual circular polarizations and a polarizer layer that utilizes a pair of sector cavities as phase delay elements for each sub-array. Two corporate feeding networks using folded E-plane and H-plane T-junctions are proposed to excite the radiating elements. Simulated results of the array antenna have shown that the axial ratios are less than 1 dB from 29 to 31 GHz for both polarizations. The realized gains for both polarizations are larger than 25 dBi at center frequency.