Watt-Level Electrical-Balanced Duplexer Front-End with Power Recycling for Full-Duplex RF Systems

This paper proposes an efficiency enhancement technique in a full-duplex electrical-balanced duplexer (EBD) front-end based on a quadrature balanced harvester (QBHV) connection at the isolation EBD port. A circuit prototype employing GaN PA devices around 400 MHz with 40% harvester efficiency measured 25% efficiency improvement (1 dB) with better than 25 dB TX-RX isolation and nonlinearity performance similar to a standalone power amplifier (PA).