Experimental evaluation of microwave field-effect-transistor noise models

Extensive GaAs field-effect-transistor noise measurements are used to compa re noise models with the aim of recommending the most useful one for monoli thic-microwave integrated-circuit design, The evaluation is based on noise and S-parameter measurements of metal-semiconductor field-effect transistor s and high electron-mobility transistors with different gatewidths in the f requency range of 0.05-26 GHz, The models under investigation differ in the number of independent coefficients necessary to calculate the four noise p arameters of the device. The broad frequency range including radio-frequenc y frequencies down to 50 MHz requires two different noise measurement syste ms with special modifications for optimum performance. In conclusion, the t wo-parameter Pospieszalski model turns out to be the most suitable one.