ACCURATE LARGE-SIGNAL GAAS-MESFET AND HEMT MODELING FOR POWER MMIC AMPLIFIER DESIGN

This article describes, from an industrial user's point of view, how l arge-signal GaAs MESFET and HEMT modeling can be done accurately and e fficiently for power MMIC amplifier design. The method is based on com mercially available CAD tools enhanced by in-house software (e.g., sma ll-signal parameter extraction, generation of load-pull contours), The Materka model is shown to predict accurately the large-signal charact eristics of GaAs MESFETs, but not of pseudomorphic HEMTs. For these de vices, a modified Angelov model is found to be adequate. A method for determining the numerous large-signal model parameters is presented. M odel verification is achieved by comparing simulated and on-wafer meas ured data like static I(V)-characteristics, multiple bias S-parameters , gain compression characteristics, and load-pull contours. Results of device scaling and calculations of optimum load impedances are discus sed, The close fit to the measured data proves that an excellent basis for large-signal power MMIC design has been established. (C) 1995 Joh n Wiley and Sons, Inc.