Wideband LNA with reactive feedback at the input matching network

Abstract

This paper presents a 3–9 GHz CMOS low noise amplifier (LNA) designed in a 0.18 μm CMOS technology which uses negative feedback with magnetic coupling at the input of a common source-LNA instead of resistive feedback. Using the proposed topology, power gain of 14.1±1 dB and noise figure between 2.24–2.45 dB was achieved in a bandwidth (BW) of 3–9 GHz. The total drawn power of the proposed circuit from a 1.5-V power supply is 5.1 mW, while the input and output matching criteria are well satisfied. The values of all elements were determined using genetic algorithms.