A Full-duplex Transceiver with Integrated Active Quasi-circulator Achieving Self-interference RF Cancellation over Wide Bandwidth

To improve the RF self-interference cancellation (SIC) of the full-duplex transceiver and extend the operating bandwidth, we propose an orthogonal-vector-synthesis (OVS)-based cancellation strategy, where an active quasi-circulator is integrated to shrink the system area and reduce the hardware overhead. The full-duplex transceiver is designed in a standard 180-nm CMOS process with layout size of 1.5mm × 1.75 mm including pads. A total SIC of more than 65 dB over wide bandwidth of 82 MHz is achieved. The noise Figure (NF) is only deteriorated by 1.5 dB.