Pseudomorphic HEMTs noise equivalent circuits extraction and physical study of noise spectral densities

Abstract

To characterize the noise behaviour of transistors, different noise equivalent circuits are used, in which the noise properties are described by noise voltage and current generators, coupled with noise impedances and admittances, and connected to the input and the output of noiseless networks that take into account all the characteristics of the transistors different from noise. Using the relation derived in this work, the equivalent circuits are extracted from the measurements of the four noise parameters; the equivalent noise resistance R/sub n/, the optimum reflection coefficient /spl Gamma/, and minimum noise figure NF/sub min/. In this way, the equivalent noise circuits of a low noise low power P-HEMT are extracted from the measurements of its noise parameters from 2 GHz to 26 GHz, and the spectral densities of their generators are presented.