A 0.7-1GHz Tunable RF Front-End Module for FDD and In-Band Full-Duplex using SOI CMOS and SAW Resonators

A 0.7-1GHz tunable front-end module (FEM) is presented for frequency-division duplexing and in-band full-duplex. It combines an electrical-balance duplexer (EBD) and tunable surface-acoustic wave resonators, demonstrating for the first time that these techniques are compatible and can be tuned independently. The EBD is integrated with a low-noise amplifier (LNA) in 0.18 mu m SOI CMOS and can operate with any antenna with a VSWR less than 2.3:1. The tunable FEM achieves more than 50dB dual-frequency isolation prior to the LNA, 2.6-3.4dB TX insertion loss and +58/+42dBm TX/RX-path out-of-bandIIP3, respectively. It has <8.8dB gain, with an input-referred, in-band gain compression point up to +27.5dBm/+11dBm caused by TX leakage or blockers, respectively.