HEMT for low noise microwaves: CAD oriented modeling

By means of an automatic measuring system which allows the rapid and accurate characterization of microwave transistors in terms of noise and scattering parameters simultaneously, 32 HEMTs of four manufacturers have been tested. From the experimental data so obtained the equivalent circuit of the `typical´ device which represents each transistor set has been extracted using a decomposition technique. This procedure allows the optimum fitting of the global performance by exploiting the correlation between the model elements and the measured parameters over the operating frequency range. Since the method takes into account also the noise behavior of several devices of each series, a substantial improvement of the model performance for use in (M)MIC CAD of low-noise amplifiers is obtained