Design optimisation of HBT broadband distributed amplifiers

Abstract

Microwave simulation of Heterojunction Bipolar Transistor (HBT) distributed amplifier is carried out by separating the HBT equivalent circuit into base and collector transmission line circuits. The characteristics of the base and collector equivalent circuit are evaluated by analysing each individual device parameter. The optimal values of Rbe, R b b and c b , have been obtained through the analysis. The relevance of feedback base collector capacitance (cbc) has also been considered in order to improve the gain-bandwidth product for an ultra broadband amplijkation.