A 21.1 mW 6.2 dB NF 77∼81 GHz CMOS low-noise amplifier with 13.5±0.5 dB S21 and excellent input and output matching for automotive radars

A low power and wideband three-stage millimeter-wave (MMW) low-noise amplifier (LNA) using standard 90 nm CMOS technology is reported. T-network (or π-match) is utilized to achieve simultaneously wideband input and output impedance matching, wideband power gain (S₂₁) and wideband NF at W-band. The LNA consumes 21.1 mW, achieving S11 better than -10 dB for frequencies 62.3~82.4 GHz, S22 better than -10 dB for frequencies 62.8~84.6 GHz, S₁₂ better than -29 dB for frequencies 72~84 GHz, and group delay variation smaller than ±6.5 ps for frequencies 70~90 GHz. Additionally, high and flat S₂₁ of 13.1±1.5 dB is achieved for frequencies 72~84 GHz, which means the corresponding 3-dB bandwidth is 12 GHz. Furthermore, the LNA achieves minimum noise figure (NF) of 6.2 dB at 78 GHz and NF of 6.8±0.6 dB for frequencies 75~82 GHz, one of the best NF results ever reported for a W-band CMOS LNA.