Shared aperture dual-mode wideband metasurface system for in-band full-duplex millimeter-wave communications

A simultaneous transmit and receive (STAR) metasurface system configuration based on shared aperture methodology is proposed for in-band full-duplex millimeter-wave communication. It is fulfilled by two separated circularly polarized (CP) feeds on both sides and the arrangement of dual-mode wideband meta-atoms that utilize CP selective property. High isolation between the transmitter (Tx) and receiver (Rx) ports of the system is realized by polarization mismatch between the Tx's CP feed and the CP selective metasurface. A wider operating bandwidth is realized by the compound geometric phase responses for both the Rx and Tx subsystems. To validate the proposed concept, a STAR metasurface system prototype to generate directional beams for a millimeter-wave communication system is designed and implemented in Ka-band. The measured port isolation is greater than 33 dB over the system operating bandwidth from 25.5 to 40 GHz (44.3%). The system prototype realizes excellent radiation performance of a joint 3-dB gain/axial-ratio bandwidth of 30.9% and 36.9%. The proposed SATR metasurface system doubles the channel throughput and enhances spectral efficiency, and thus employed to deal with congestion of the electromagnetic spectrum for high-throughput wireless communication.