Relationships between common emitter, common base and common collector HBTs

Analytical expressions for the relationships between common emitter, common base and common collector HBTs are presented in this article. Further simplified expressions for noise parameters in the low frequency range are given. This technique is based on the combination of an equivalent circuit model and a conventional two-port network signal/noise correlation matrix technique. The derived relationships have universal validity, but they have been verified with InP/InGaAs DHBTs with a 5 × 5 μm ² emitter area. Good agreement has been obtained between calculated and measured results.