Ultra-wideband low noise amplifier using a cascode feedback topology

An ultra-wideband (UWB) low noise amplifier (LNA) that consists of two cascode and shunt feedback stages is presented. Measurement results show the maximum power gain (S-21) of 11.9 dB with the 3-dB band from 2 to 6.5 GHz and input/output reflection coefficient (S-11, S-22) of less than -7.8 dB from 2 to 11 GHz. In addition, the fabricated LNA achieves the average noise figure (NF) of 4.5 dB from 2 to 10 GHz, which value is much lower than previously reported state-of-the-art UWB amplifiers. The input-referred third-order intercept point (IIP3) and the input-referred 1-dB compression point (P-1dB) of the LNA are achieved as 4 dBm and -5 dBm, respectively, while consuming 27 mW in 0.18 mu m RF CMOS process.