Nonlinear Microwave Modelling Approaches for GaN and GaAs FETs in the Presence of Low-Frequency Dispersive Effects

Low-frequency dispersive phenomena due to self-heating and charge trapping in GaN and GaAs- based FETs often lead to somehow reduced microwave circuit performances with respect to nominal expectations. Thus, state of the art microwave circuit designs can only be achieved by embedding accurate models of the dynamic drain current characteristics into the overall nonlinear device description. In this Short Course, special focus is on the drain current model solutions and limitations affecting the accurate prediction of the most important power amplifier performance indicators, such as RF output power, power gain, power supply current consumption and energetic efficiency. Well-known and new nonlinear modeling approaches are reviewed also in relation with their experimental identification procedures and their practical implementation into commercial CAD tools.