Co-Polarized In-Band Full-Duplex Cavity Slot Antenna Array Based on Wavefront Phase Compensation

This article proposes a methodology for designing co-polarized in-band full-duplex (IBFD) antenna arrays with high isolation. An equivalent circuit model of IBFD antenna arrays is established, and transmission zeros are introduced by configuring controllable coupling paths between the arrays. Based on the proposed equivalent circuit model, the high-isolation co-polarized IBFD antenna arrays are designed by utilizing a wavefront phase compensation technique and a controllable coupling structure. Two co-polarized IBFD cavity slot antenna arrays based on the TM510 mode cavity are designed for validation, where a transmission zero is obtained in the passband to improve the isolation between the transmitter (Tx) and the receiver (Rx) ports. Compared with the reference antenna array, the isolation of the designed IBFD antenna array is improved by about 22 dB. The theoretical analysis and design process of the IBFD antenna array is given in detail. A second-order co-polarized IBFD antenna array is fabricated and measured, and the measured results are in good agreement with the simulated results.