The importance of gate charge formulation in large-signal PHEMT modeling

A critical step in developing accurate large signal PHEMT models is the equation used for the gate charge. This paper examines three types of gate charge formulations. Measured versus modeled results at 2, 8 and 16 GHz clearly demonstrate that a two terminal voltage dependent gate charge model provides the best prediction of all the parameters measured, namely : output power, PAE, drain current, harmonic power, and 3rd order intermodulation distortion products Ga.