23–32/31–44 GHz Reconfigurable Dual-Band VGA for 5G mm-wave Communication Transmitters

This letter presents a 23–32/31–44 GHz reconfigurable dual-band variable gain amplifier (VGA) for 5G mm-wave transmitters. The design utilizes a constant phase structure with phase-compensation-circuits (PCCs) to minimize phase variation, while a high-impedance-ratio reconfigurable interstage matching network (ITMN) enables dual-band switching. To meet the requirement for high output power in mm-wave transmitters, load-pull is carried out to maximize the output 1 dB compression point (OP${}_{1\text {dB}}$). Fabricated in TSMC 28-nm bulk CMOS process, the proposed VGA achieves a peak${S} {_{21}}$of 9.7/9.3 dB at 23–32/31–44 GHz with a gain tuning range of 18/16 dB. It delivers an OP${}_{1\text {dB}}$of 4.6/3.7 dBm at its maximum gain states. The rms phase error is below 0.9°/1.9°/0.4°/0.7° across 5G bands n258/n257/n260/n259. The circuit consumes 25.5 mW with a core size of 0.22 mm2. With the aforementioned performance, the proposed VGA is highly competitive for 5G mm-wave mobile communication transmitters.