A resistive-feedback LNA in 65 nm CMOS with a gate inductor for bandwidth extension

In order to get a wideband and flat gain, a resistive-feedback LNA using a gate inductor to extend bandwidth is proposed in this paper. This LNA is based on an improved resistive-feedback topology with a source follower feedback to match input. A relative small inductor is connected in series to transistors gate, which boosts transistors effective transconductance, compensates gain loss and then leads the proposed LNA with a flat gain and wider bandwidth. Moreover, the LNAs noise is partially inhibited by the gate inductor, especially at high frequency. Realized in standard 65-nm CMOS process, this LNA dissipates 12 mW from a 1.5-V supply while its core area is 0.076 mm². Across 0.4-10.6 GHz band, the proposed LNA provides 9.5±0.9 dB power gain (S₂₁), better than -11-dB input matching, 3.5-dB minimum noise figure, and higher than -17.2-dBm P_{1 dB}.