New formulation of Cardiff behavioral model including DC bias voltage dependence

A new mathematical formulation for the Cardiff nonlinear behavioral model is presented in this work which includes the dc bias voltages (drain and gate) into the model. It has been verified by modeling a GaN on SiC high electron mobility transistor (HEMT) at 3.5 GHz. For the case presented, interpolation of load-pull data has resulted in a more than 90% reduction in the density of the load-pull data required to generate a nonlinear behavioral model over a wide range of dc bias points.