Self-Interference Cancellation Antenna Using Auxiliary Port Reflection for Full-Duplex Application

An aperture-coupled microstrip patch antenna pair with wideband self-interference cancellation (SIC) performance is proposed. It consists of two orthogonal linearly polarized antennas and an auxiliary port loaded with a proper reflective terminal. Besides the direct coupling between two antennas, an indirect coupling path is introduced and controlled by the auxiliary port reflection. The coupling between these two paths will superpose and cause cancellation at the receiving antenna output, while a high isolation between the antennas can be achieved accordingly. For the validation of the proposed SIC, one prototype was designed and fabricated. Good agreement can be observed between the simulated and measured results. A high isolation of 35.9-46.5 dB over the entire working band of (2.40-2.62 GHz) is observed, while the radiation patterns are almost the same for the antenna pairs with and without SIC circuit. Due to the merits of good performances and easy implementation, the proposed SIC technique has potential application for full-duplex transceiver to suppress the self-interference.