Choosing an optimum large signal model for GaAs MESFETs and HEMTs

Abstract

Seven large signal MESFET models and three newly developed HEMT (high-electron-mobility transistor) models have been compared, providing the microwave circuit designer with a practical benchmark. The error for each model is quantified and minimized using a modified Newton's method with the restricted step technique of K. Levenberg (1944) and D. Marquardt (1963). This minimum obtainable error is used as a basis for comparing the models. The validity of this approach is confirmed by comparing predicted to measured large-signal performance made on a Triquint 0.5- mu m-gate-length MESFET. The model comparison tool has also been utilized to develop a general approach to large signal HEMT modeling for circuit simulation applications. A 0.7- mu m-gate-length pseudomorphic HEMT device was used for this portion of the study.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>