Millimeter Wave Circularly Polarized Full Duplex Antenna Array with High Isolation

A circularly polarized full-duplex antenna array is designed for a 60 GHz wireless transmission chip. Firstly, a dual-polarization antenna based on the cavity-backed slot is designed. Two orthogonal modes
$(\text{TE}_{120}$
and
$\text{TE}_{210})$
are used to realize two different polarization states of the antenna, thus effectively reducing cross-polarization. A layered feeding structure is adopted in the design, which can enhance the isolation between the two ports. Then a circularly polarized antenna array is proposed based on the proposed dual-polarization antenna. The four antennas are rotated 90° around the phase center of the array to achieve the right-hand circular polarization function. The simulation results show that the antenna can operate between 63.3 to 64.5 GHz with isolation of 37 dB between the transmitting and receiving ports.