Direct parameter extraction method for InP heterojunction bipolar transistors based on the combination of T- and -models up to 110GHz

A parameter-extraction approach for determination of the small-signal equivalent circuit model for InP/InGaAs double heterojunction bipolar transistors is presented in this paper. This method combines the advantages of conventional T- and pi-type equivalent-circuit topologies. All the equivalent circuit elements are only extracted analytically from S-parameter data without any numerical optimization. The agreements between the measured and the model-calculated data are excellent in the frequency range of 0.1-110 GHz.