A Dual Circular-Polarized Antenna for mmWave Wireless Communications

This paper presents our study on an antenna with dual circular polarization operating in W-Band. The antenna is capable of transmitting and receiving two orthogonal circular polarized signals (Left Hand Circular Polarization and Right Hand Circular Polarization) simultaneously to achieve Full-Duplex hence twofold spectrum efficiency in mmWave wireless communication systems. It mainly consists of a stepped septum polarizer and a profiled smooth-wall horn. The fabricated antenna shows 21% relative bandwidth from 76.8 GHz to 95 GHz with AR < 1.9 dB, the return loss is better than 15 dB and isolation > 20 dB for both LHCP and RHCP. It is also quite suitable to be used as a feed for a reflector antenna when high gain is also required besides high spectrum efficiency.