Wideband Low-Noise Amplifiers Aiming at Achieving Transistor Fmin

Abstract

Many RF receivers operate over wide bandwidths and required wideband low-noise amplifiers (LNAs). While there are many wideband LNA topologies available, only some of them are able to achieve noise factors that are close to the lowest noise factors offered by a given semiconductor technology. This article complements an earlier RFIC Virtual Journal article from April 2014 by focusing on LNA topologies that are theoretically able to exhibit both wideband input match and wideband noise matching. Three broad groups of input matching strategies are identified as promising for the implementation of very-low-noise wideband amplifiers. With the focus on wideband LNA noise, this article does not consider LNA linearity, gain, and power consumption.