A Reconfigurable LNA With Compact Magnetic-Capacitive Coupling Transformer Networks for 5G 28-/39-GHz Applications

This letter presents a frequency reconfigurable low-noise amplifier (LNA) for 5G 28-/39-GHz bands applications. In the proposed LNA, a wideband input common-source amplifier is designed to cover both 28- and 39-GHz bands, and following two parallel switchable common-gate amplifiers are leveraged to split the RF signal into two independent signal paths. Thus, the output single-band amplifiers could be optimized flexibly at each target operating band with area-efficient magnetic-capacitive coupling transformer-based matching networks, improving the amplifier power gain, noise figure, and out-of-band signal rejection performance. Fabricated in a 65-nm CMOS process, the proposed LNA has a compact die size of only 0.1 mm2 and achieves 16.6-/15-dB peak gain, 4.06-/4.46-dB minimum NF, and -12.1-/-16.5-dBm IP1dB at 28-/39-GHz bands, respectively, while consuming 26.4 mW from a 1.2-V power supply.