A Wideband Monostatic Co-Circularly Polarized Simultaneous Transmit and Receive Antenna for 60-GHz Applications

A wideband monostatic Co-circularly polarized (CP) simultaneous transmit and receive (STAR) antenna is proposed for 60-GHz applications. The proposed antenna system consists of four dual-polarized magneto-electric (ME) dipole antenna elements and two sequentially rotated feeding networks using ideal circuit components. The four ME dipole elements have been arranged in a 2×2 array for monostatic STAR operation. To ensure uniform left-handed circular polarization (LHCP) for both transmit (TX) and receive (RX) channels, as well as high TX/RX isolation, the four TX and RX ports of the STAR antennas are fed with equal amplitude and relative phase values of 0°, 90°, 180°, and 270°, respectively. The proposed STAR antenna system effectively reduces self-interference (SI) between TX and RX, achieving an optimal isolation of over 110dB in simulation. Moreover, TX and RX antennas demonstrates similar performance characteristics, both with an impedance bandwidth of over 20%, an axial ratio (AR) bandwidth of more than 20%, and maintaining a stable gain of approximately 11dBic across the operating band.