A Ku-Band +2 dBm IIP3 Transformer-Based LNA with Loop-Gain-Enhanced Capacitive Negative Feedback

This letter presents a novel Ku-band capacitive negative feedback (CNF) low-noise amplifier (LNA). The loop-gain-enhanced capacitive negative feedback technique proposed in this work can suppress the noise contribution of the common-gate transistor in the first cascode stage, simultaneously enhancing the linearity of the overall LNA within the desired frequency band. Moreover, wideband operation is guaranteed through the utilization of the staggered tuning technique and the bandwidth extension technique. The measured results show that the proposed LNA, implemented in TSMC 180nm CMOS technology, achieves a peak gain of 17.1 dB with the 3-dB bandwidth ranging from 9.9 GHz to 13.5 GHz. The minimum noise figure (NF) within the desired band is 4.4 dB, with an IIP3 of +2 dBm, while consuming 28.8 mW of power. The core area of the proposed LNA is 0.6 mm².