A Wideband 7.5-29.5 GHz LNA with Constant NF by Using Multistage Noise Matching at High Frequencies

Abstract

A wideband low noise amplifier (LNA) operating within 7.5-29.5 GHz with constant NF variation is presented. Different with conventional noise matching method aiming to realize noise matching across the whole wide bandwidth, the noise matching is only implemented at high frequencies and thus very flat NF is achieved in this work. To further improve noise performance, the multistage noise matching technique is adopted and demonstrated. In addition, to boost the gain and save the power consumption, the CMOS transistor pair is adopted to enhance the transconductance. According to post-layout simulations, the LNA shows the maximum power gain of 15.4 dB, and the noise Figure (NF) ranging from 3.3 to 3.4 dB. The input third-order intercept point (IIP3) is -3.8 dBm at 15 GHz. Implemented in TSMC’s 65-nm CMOS process, the LNA die (including pads) occupies an area of 0.31 mm2.