PRINCIPLES OF LARGE-SIGNAL MESFET OPERATION

The large-signal RF operating principles of MES-FET amplifiers are inv estigated using a circuit simulator that incorporates a physics based MESFET model which has been augmented with a new gate breakdown model. It is demonstrated that the main saturating mechanisms of the MESFET under large-signal RF operation are forward and reverse conduction of the gate electrode. Maximized RF performance of MESFET amplifiers is o btained by optimally positioning the dynamic load line relative to the RF-IV plane. The position of the dynamic v-i characteristic is determ ined by device breakdown, bias, and circuit tuning conditions.