A 64-84 GHz CMOS LNA with Excellent Gain Flatness for Wideband mmW Applications

This paper presents a wideband millimeter wave (mmW) LNA fabricated in a 55-nm CMOS process. Inter-stage transformer peak splitting and gain equalization techniques are proposed to improve bandwidth and gain flatness. A transformer- based anti-phase coupling (TBAC) method is developed to en­hance effective transconductance boosting, while optimizing noise figure (NF). The LNA achieves a peak gain of 11.8 dB with a gain variation of less than ±0.8 dB, a flat gain bandwidth (FGBW) of 15 GHz (66-81 GHz) and a BW-3dB of 20 GHz (64-84 GHz). The measured NFmin is 5.09 dB at 75 GHz and the input-referred 1dB compression point (IPidB) is -5.8 dBm at 78 GHz. The LNA consumes 40 mA from 1 V power supply.