A 5–6 GHz CMOS RF Front-End Module for FTTR Application

This paper presents a 5–6 GHz RF front-end module (FEM) integrating a power amplifier (PA), a low-noise amplifier (LNA), and a T/R switch. The proposed switch enables the matching network of the receiver (Rx) and transmitter (Tx) to reuse the transformer and capacitor. Meanwhile, the PMOS switch is re-used to compensate for the AM-PM distortion of the PA. The compact layout minimizes the parasitics and optimizes the switching time. The chip is fabricated in a 55-nm CMOS process. Measurement results show that the high and low gain variation of Rx/Tx at 5–6 GHz is greater than 10 dB. The measured noise figure (NF) of Rx is less than 4.0 dB in high-gain mode (including the T/R Switch and off-mode PA). The measured output power 1 dB compression point (OP1dB) of Tx is better than 11.55 dBm (including the T/R Switch and off-mode LNA). The error vector magnitude (EVM) of the Tx is better than -35 dB at 0 dBm output power with 80-MHz 256-QAM orthogonal frequency division multiplexing (OFDM) signal. The switching time of the Tx/Rx is less than 112 ns. The chip area of FEM is $0.12\times 0.15\text{mm}^{2}$ excluding I/O pads.