Development of RF equivalent circuit models from physics-based device models

Modern device modeling codes enable the designer to simulate the behavior of nearly arbitrary 3-dimensional semiconductor device structures with multiple electrodes. However, the output of such programs is not a lumped element model that can be used in the design of RF circuits. Rather, such programs produce a (hopefully) good simulation of an experimental situation, as described by the device static and RF characteristics. As far as RF modeling is concerned, the conventional use of device simulators boils down to imitating the RF scattering experiment from which one can obtain parameters of a pre-conceived lumpedelement model. Clearly, this procedure suffers from the same limitations as fitting to experiment. I would like to discuss a different approach to this problem, based on physical device modeling without any pre-conceived circuit topology.