An approach to determine cutoff frequency and maximum oscillation frequency of common emitter heterojunction bipolar transistor

Abstract

AbstractAnalytical expressions for the short‐circuit current gain and unilateral power gain of common emitter heterojunction bipolar transistor (HBT) are presented in this paper. These expressions are derived from a simplified π‐type small signal equivalent circuit model, which takes into account the influence of the extrinsic resistances and base‐collector capacitance distributed nature. Good agreement is obtained between measured and calculated results for both two indium phosphide (InP) HBT devices and a gallium arsenide (GaAs) HBT device over a wide range of bias points.