39 GHz Transmit/Receive Front-End-Module With Back-Off Efficiency Enhancement for 5G Communication

This paper presents a transmit/receive (TX/RX) front-end module (FEM) featuring enhanced back-off (BO) efficiency and low noise figure (NF) for fifth-generation wireless infrastructure. Specifically, it proposes a TX/RX combiner that performs necessary Doherty’s load modulation for enhancing the TX’s efficiency in BO and carefully incorporates a switch in the RX side to maximize isolation and optimize the tradeoff between RX NF and TX power efficiency while maintaining a compact area. A circuit demonstrator is implemented using the 45 nm silicon-on-insulator CMOS process. Measurement results demonstrate 15 dB small signal gain, 20 dBm output power with 23% and 15% power added efficiency at peak and 6 dB BO in TX mode, and 20 dB small signal gain with a 4.5 dB NF and -16 dBm IP1dB while consuming only 32 mW in RX mode. The overall core size of the TX/RX FEM is 0.5×0.75 mm².