I. Introduction
Artificial neural network (ANN) technology has become a versatile, powerful, and efficient tool for the general representation of transistor model multi-dimensional constitutive relations (e.g. terminal currents and charges as nonlinear functions of intrinsic terminal voltages, junction temperature, and trapped charge) from measurements, in a form useful for a wide variety of compound semiconductor technologies, and deployed in a wide range of simulations (DC, S-parameter, harmonic balance, etc) [1].