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

This paper describes from an industrial user's point of view how large-signal GaAs MESFET modeling can be done accurately and efficiently for a power MMIC amplifier design. The method is based on the use of a harmonic balance simulator and an optimizer dedicated to large-signal parameter extraction, which are both commercially available packages. Appropriate interfaces required by the measurement systems and in-house software, including small-signal parameter extraction and generation of load-pull contours, were added to the independent software packages. Because of its topology and accuracy, the Materka large-signal MESFET model is selected. A method for determining its 22 parameters is presented. Model verification is done by comparing simulated and on-wafer measured data, including the static I-V characteristics, S-parameters, gain compression characteristics and load-pull contours. Results of device scaling and calculations of optimum load impedances are discussed. The obtained close fit with measured data proves that useful large-signal power MMIC design criteria have been established.