High-Isolation Dual-Polarized Antenna for Wideband Full-Duplex Systems

A new four-port dual-polarized antenna for in-band full duplex (IBFD) operation is presented offering high inter-port isolation. The antenna consists of four H-shape slots, stacked patches for wide bandwidth, and two 180° hybrid couplers. The multilayer antenna is well matched from about 2.2 to 2.4 GHz and provides high isolation, and with the addition of external hybrid couplers, the simulated coupling between the ports is below 60 dB. When compared to other types of similar hybrid coupler and antenna systems, the proposed configuration provides a higher isolation bandwidth (10%) and higher gain. As reported in the paper, simulation and measurement results are in good agreement and suggest that maximum realized gain values of 7.8 dBi are possible with cross-polarization levels of 30 dB or lower. To the best knowledge of the authors' no similar antenna system has been previously reported in the literature with similar operating bandwidths and isolation values in the S-band which can enable new data link possibilities for future IBFD wireless networks.