Extracción y estudio de la dependencia con la polarización y la temperatura del modelo pequeña señal para transistores encapsulados GaAs MESFET

Abstract

An extraction technique of the small signal equivalent circuit parameters of GaAs MESFET packaged transistor and their dependence on both bias and temperature are presented. This method is based on four steps which are: 1) extrinsic elements (package elements not included) are extracted from S parameters measurements of the transistor biased under cold and pinch-off condition, 2) package effects parameters are then determined through optimisation from S parameters measurements of the transistor under pinch-off condition, 3) the optimal extrinsic parameters, including package parameters, are searched through optimization algorithm from S parameters measurements of the transistor biased at normal condition (hot transistor) using the starting values already obtained. This step allows us to obtain independent intrinsic elements of frequency and finally 4) the temperature and bias-dependent intrinsic elements are directly extracted from multi-bias S parameters measurement over a wide rang of temperature (from -30ºC to +70ºC). The validity of the proposed method and the small signal model is verified by comparing the simulated wide band S parameters, over a wide bias and temperature range, with measured data of a GaAs MESFET transistor.