A K-Band Ultra-Compact Gm-Boost LNA Using One Multi-Coupled Transformer in 65-nm CMOS

This letter presents an ultra-compact gm-boost low noise amplifier (LNA) with only one multi-coupled transformer for the first time. Implemented in 65-nm CMOS process, the proposed LNA achieves a measured peak gain of 10.5 dB with its 3-dB bandwidth ranging from 21 to 34.5 GHz and a noise figure (NF) of 2.5 dB at 28 GHz, while consuming 4-mW dc power. Based on the superior compactness of the transformer, the core area of the LNA is optimized to only
$0.03~{\text {mm}}^{2}$
.