Analysis and Design of a CMOS Low Noise Amplifier for 3-5 GHz UWB Systems

This paper presents an ultra-wideband (UWB) CMOS low noise amplifier (LNA) that combines a narrowband LNA with resistive shunt- feedback. A new feedback topology is proposed based on the analysis of the influences of feedback scheme on the performances of the LNA. The noise figure (NF) and the power gain, compared with those of a previous shunt-feedback LNA topology, are decreased by 0.8 dB and increased by 2.5 dB respectively while other performances have little change. Designed in a 0.18- mum CMOS technology, the LNA shows a minimum NF of 2.2 dB, a power gain of 11 dB with plusmn0.6 dB variation, and an input return loss of more than 9 dB over the 3.1-5 GHz UWB band.