A 10.56-GHz Broadband Transceiver With Integrated T/R Switching via Matching Network Reuse and 0.3–2.1-GHz Baseband in 28-nm CMOS Technology

This paper presents a 10.56-GHz transceiver with ultracompact transformer-based transmit/receive (T/R) switching via matching network reuse. The reused transformer can operate as T/R switch and impedance matching networks for a power amplifier (PA) and a low-noise amplifier (LNA) simultaneously. The T/R switch, PA, and LNA are fully codesigned, and the interstage matching networks of the PA and LNA are comatched with the T/R switch to improve the performance of the front end (FE). A three-coil transformer is introduced in the PA to improve the linearity and bandwidth of the FE in the transmit (TX) mode. A mode selection unit (MSU) is also utilized in LNA to improve the TX/RX isolation and the linearity of the FE in the TX mode. Utilizing the fully codesign technique in the FE, the bandwidth of the FE is extended to over 4.2 GHz in both the TX and RX modes. A novel “gm-cell-based” broadband programmable gain amplifier (PGA) and a third-order transconductance-capacitor (gm-c) low-pass filter (LPF) are used in analog baseband to provide over 24-dB gain and 1.8-GHz bandwidth adjustment range with ultralow dc power consumption. To prove the concept, the new architecture is implemented in 28-nm CMOS technology. Measurement results prove that the insertion loss of the proposed T/R switch introduced in both the TX and RX modes is ~0.5 dB, and benefiting from this, the RX obtained a 4.2-dB noise figure, and TX obtained 9.9and 14.1-dBm OP1dB and Psat. The measured single sideband bandwidth of the transceiver is wider than 2.1 GHz in both the TX and RX modes.