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

This paper presents a frequency reconfigurable dual-band load-insensitive transmit/receive (T/R) front-end (FE). The proposed T/R FE chip is composed of a frequency reconfigurable dual-band load-insensitive power amplifier (PA), a frequency reconfigurable dual-band low-noise amplifier (LNA), and a compact ultra-wideband T/R switch at the antenna interface. Frequency reconfigurability is realized by integrating switches into matching networks. TX load insensitivity is realized by balanced architecture and a novel proposed cross-coupled adaptive bias scheme. Fabricated in 28-nm bulk CMOS process, the measured results show that in RX mode, the FE realized a peak gain of 15.2/18.2 dB at low band and high band with bandwidths of 21.5–27 GHz and 28.5–37.5 GHz, respectively. The NF at both bands is smaller than 5.5 dB. In TX mode, the FE realized a peak gain of 21.1/20.4 dB at low band and high band with bandwidths of 22.8–29.5 GHz and 30–36.8 GHz, respectively. The OP1dB/Psat/PAEmax are larger than 15.8 dBm/16.6 dBm/11.8% at both bands. Under load variations corresponding to a voltage standing-wave ratio (VSWR) of 2.5:1, the proposed FE exhibits gain/OP1dB deviations from the 50-Ω condition of less than 1.7/2 dB at the low band, and less than 1.5/1.7 dB at the high band, respectively. To the best of the authors’ knowledge, this is the first front-end that achieves band switching with TX VSWR-resilient performance.