Direct extraction of equivalent circuit model parameters for HBTs

An analytical method for the direct extraction of small-signal equivalent circuit model parameters for gallium arsenide heterojunction bipolar transistors has been developed. This method completely eliminates the need for parameter optimization and provides the best agreement between modeled and measured S-parameters ever reported. The resulting models have been shown to be valid from 0.5 GHz to 20 GHz. Furthermore, it works extremely well over a very broad bias range. This analytical method, which uses a hybrid T equivalent circuit, provides unique and meaningful circuit model parameters.