An Integrated Reconfigurable SAW-Less Quadrature Balanced N-Path Transceiver for Frequency-Division and Half Duplex Wireless

Abstract

In this work, we propose a fully integrated transceiver for frequency-division and half duplex wireless operation based on a quadrature balanced N-path mixer-first architecture. The quadrature balanced N-path transceiver (QBNT) comprises a quadrature hybrid and two identical mixer-first receivers (MFRXs), presenting a short circuit and 50 ohms matching in the transceiver (TX) and receiver (RX) bands, respectively. The TX power reflects at the MFRXs' interface and adds up in-phase at the antenna, while the RX signal from the antenna is reconstructed in phase in digital baseband, with the TX noise cancelled at RX regardless of antenna voltage standing wave ratio. QBNT equations and design considerations are shown. An integrated QBNT prototype was fabricated in TSMC 65nm CMOS process as a proof of concept, occupying an active area of 2.96 mm2, The QBNT operates at the frequency range between 0.75-2 GHz with a TX-RX offset above 200 MHz. It achieves RX noise figure (NF) of 2.8-5.8 dB, RXB1dB of 18 dBm, TX-ANT OIP3 of 27.3 dBm and 29.5 dBm in FDD and half duplex (HD) modes, respectively. The RX and TX (at OP1dB) consume DC power of 82–130 m Wand 254 m W, respectively.