A 2.35 GHz Cross-Talk Canceller for 2×2 MIMO Full-Duplex Wireless System

A reciprocal network to mitigate cross-talk induced interference (CI) in a 2×2 Multiple Input Multiple Output (MIMO) wireless node operating in same-channel full-duplex (SCFD) mode is proposed. Reciprocal nature of channel between the two antennas of the MIMO node is exploited to simplify the design of cancellation network. A canceller board is designed and fabricated on an FR4 PCB to test the proposed technique. Measurements on the board connected to a dual-port antenna mounted in lab environment show CI cancellation of more than 55dB in 20MHz bandwidth around 2.35 GHz. Self interference (SI) is also cancelled to more than 35dB in the 20 MHz bandwidth. Measured results with modulated 20MHz +30 dBm signal applied at transmit ports are also shown.