A 77.3-GHz 3.36-dB NF LNA Using Cross-Coupled Noise Cancellation and Low-Loss Input Matching Transformer in 22nm CMOS

This paper presents a 77-GHz low-noise amplifier (LNA) for automotive radar applications. A hybrid common-source (CS)/common-gate (CG) first stage with cross-coupled noise cancellation (CC-NC) is proposed to simultaneously achieve low input impedance (Zin), intrinsic noise suppression, and effective transconductance (Gm) boosting. Thanks to the low input impedance, a 1:1 transformer-based input matching network (IMN) with high coupling coefficient and quality factor becomes feasible, reducing insertion loss (IL) compared to conventional loss-limited 1:2 transformers in W-band LNAs. The subsequent stages employ neutralization and inductive degeneration to achieve simultaneous noise and power matching while ensuring high gain and stability. The prototype, implemented in 22-nm bulk CMOS, achieves a peak gain of 26.2 dB at 77.3 GHz with a 4.6-GHz bandwidth. A minimum measured noise figure (NF) of 3.36 dB is achieved at 76 GHz while consuming 18.6mW from a 0.9-V supply, demonstrating state-of-the-art noise performance for bulk CMOS millimeter-wave LNAs.