Implementation of a Noise Model and Extraction Method for GaAs MESFETs

A noise model for GaAs MESFETs based on the small signal equivalent circuit is described. The model is a variation of that described by Pospieszalski. It is shown that good agreement between measured and modeled noise performance can be obtained by varying a single parameter in the model, namely the drain noise current iDn, which may be obtained by measuring the device noise figure at a single frequency. It is shown that iDn scales linearly with drain bias current. Therefore, a complete noise description of the MESFET may be determined from the equivalent circuit and bias point.