A Wideband Dual-Circular-Polarization Horn Antenna for mmWave Wireless Communications

This letter presents our design and experimental verification of a wideband dual-circular-polarized antenna operating in the W-band based on an optimized waveguide septum polarizer and a profiled smooth-wall horn. This antenna is capable of transmitting and receiving two orthogonal circular-polarized signals [left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP)] simultaneously to achieve full-duplex, hence, twofold spectrum efficiency for millimeter-wave (mmWave) wireless communications. The fabricated antenna shows 21% relative bandwidth from 76.8 to 94.7 GHz with axial ratio <5.8 dB; the reflection coefficient is below −15 dB and isolation >20 dB for both LHCP and RHCP.