3.1 dB NF 20-29 GHz CMOS UWB LNA using a T-match input network

A 20-29 GHz CMOS ultra-wideband (UWB) low-noise amplifier (LNA) with excellent input return loss (S₁₁), flat and high power gain (S₂₁), and flat and low noise figure (NF) is demonstrated. Wideband input impedance matching was achieved by using the proposed T-match input network to generate two S₁₁ dips. Flat and high S₂₁ was achieved because the inductive-peaking second stage and the current-reused final two stages can compensate the gain degradation of the source-degenerative first stage at medium and high frequencies, respectively. Flat and low NF was achieved by adopting a slightly under-damped Q-factor for the second-order NF frequency response. The LNA consumed 22.07 mW and achieved S₁₁ of -15.5 to -26.8 dB, S₂₁ of 16.2±2.5 dB, minimum NF (NFmin) of 3.1 dB (at 20 GHz), and an average NF of 3.6 dB over the 20-29 GHz band of interest, one of the best reported average NF performances for a 24 GHz band CMOS LNA with bandwidth wider than 6 GHz in the literature.