Modeling and performance simulation techniques of GaAs MESFET's for microwave power amplifiers

The problem of measuring, modelling and analyzing MESFET's when operating as microwave power amplifiers at frequencies up to X band was studied. Transistor nonlinear models are reviewed, and measurements of their parameters are described. Computer simulation of microwave MESFET amplifiers was performed by a harmonic balance technique. Results of measurements performed at amplifier level are presented and compared with those obtained from simulation. Measured and computed values of small signal S parameters of the transistor agree well. Computed gain in linear output is 1.4 dB less than experimental value. Agreement is very good for nonlinear behavior and for intermodulation products.