A Millimeter-Wave Frequency Reconfigurable Dual-Band T/R Front-End for 2.5:1 VSWR-Resilient in TX Operations

This paper presents a frequency-reconfigurable dual-band load-insensitive transmit/receive (T/R) front-end (FE). Frequency reconfiguration is achieved by embedding switches into the matching networks. Load insensitivity in TX mode is realized using a balanced architecture combined with a novel cross-coupled adaptive bias scheme. Fabricated in a 28-nm bulk CMOS process, the FE achieves RX gains of 15.2/18.2 dB over 21.5–27 GHz and 28.5–37.5 GHz, with NF below 5.5 dB. In TX mode, peak gains of 21.1/20.4 dB are obtained over 22.8–29.5 GHz and 30–36.8 GHz, with OP1dB/Psat/PAEmax exceeding 15.8 dBm/16.6 dBm/11.8%. Under VSWR = 2.5:1, gain and OP1dB deviations remain below 1.7/2 dB. To the best of the authors’ knowledge, this is the first front-end which realized band switching function with TX VSWR resilient performance.