Noise modeling in MESFET and HEMT mixers using a uniform noisy line model

The aim of this paper is to present a noise model which predicts the noise performance of MESFET and HEMT mixers. The conversion and noise correlation matrices of a FET mixer are calculated using a uniform nonlinear noisy active line concept to describe the FET. This calculation is based on a perturbation analysis of the large-signal noiseless steady state, making it a "microscopic nonlinear noise model". This method is applied to the case of a hot HEMT gate mixer and we show that the theoretical results are in agreement with experimental data.