Dual-Polarization Multi-Layer Antenna by Patch Asymmetry with Simple Integrated Feeding for In-Band Full-Duplex Systems

A new two-port dual-polarized antenna for In-Band Full-Duplex (IBFD) applications is proposed. The antenna consists of two H-shaped slots, asymmetrical stacked aperture coupled patches to improve bandwidth, and a simple Rat-Race hybrid coupler feeding system integrated within the antenna system. In this configuration, antenna port one can provide a differential phase shift of 180° between two H-shaped slots to excite linear polarization, while port two can generate an orthogonal linearly polarized mode. Using such a feeding scheme and patch asymmetry, only one hybrid coupler is required for dual-polarization. The antenna is well matched from about 2.3 to 2.4 GHz while isolation levels are above 35 dB. Maximum realized gains are 7.1 dBi and 8.2 dBi for port one and two, respectively. Using such a simple feeding approach and asymmetrical antenna layout, there are no requirements for connecting cables or additional external couplers which significantly simplifies the antenna system.