A ± 45 ° dual-polarized co-channel patch antenna array for in-band full-duplex applications

A broadband stacked patch antenna array with high port isolation is presented for in -band full -duplex (IBFD) applications in this article. A co -channel feeding scheme is proposed to simultaneously excite two ports of the patch antenna to achieve +/- 45 degrees dual polarization. An antenna system is then designed using a 2 x 2 stacked patch array, a parallel feeding network, and a hybrid coupler. The coupling between the Tx and Rx ports due to mismatch and coupling between the antenna elements is analysed in detail and shown to be eliminated completely. A demonstrator is fabricated and measured to endorse the accuracy of the proposed feeding scheme. The measured results show that the developed prototype can operate from 3.15 GHz to 4.0 GHz. The isolation level between Tx and Rx ports is higher than 45 dB within the operating band. The realized gains of two ports are higher than 10.5 dBi throughout the band of interest with the maximum gain of 13.9 dBi, which are congruent with the simulated ones.