A GaN HEMT Global Large-Signal Model Including Charge Trapping for Multibias Operation

This paper presents a novel empirical model for gallium nitride on silicon carbide high-electron mobility transistors. A global state-space formulation describes charge trapping effects by means of suitable 2-D nonlinear lag functions of the applied voltages, extracted from a reduced set of double-pulse current-voltage characteristics. The implementation in CAD tools involves a simple equivalent circuit and lookup tables, making the model well suited for power amplifier design in the presence of signals of practical interest. An extensive validation at both low (4 MHz) and radio frequencies (5.5 GHz) exhibits good accuracy and a robust performance prediction for the operation above the cut-off of dispersive phenomena, across different operating classes and loads, in terms of output power, power-added efficiency, and third-order intermodulation distortion. These results show that traps with both linear and nonlinear dynamics are stimulated in large-signal operation, and that these must be taken into account for global model predictions.