A Code-Domain RF Signal Processing Front End With High Self-Interference Rejection and Power Handling for Simultaneous Transmit and Receive

A code-domain transceiver front end that incorporates a transmit modulator and a receive (RX) RF signal correlator is presented. An integrate-and-dump N-path filter improves rejection by 8 dB. We propose an RF chopper switch with 12.1-/23.1-dBm P1dB/IIP3 for both RF correlation and filtering that rejects TX self-interference by 49.5 dB. Walsh and Barker codes are generated with fine and coarse tuning for synchronization. The RX power consumption is 18 mW, including dynamic power (1-V supply) and four analog amplifiers (1.5 V) at the operating frequency of 1 GHz and the code rate of 200 megachip-per-second (Mc/s). The TX modulator operates to RF power levels up to 34.3 dBm and consumes less than 40 mW for 300 Mc/s. Over the air testing demonstrates synchronization with Barker codes.