SMALL-SIGNAL DISTRIBUTED MODEL FOR GAAS HBTS AND S-PARAMETER PREDICTION AT MILLIMETER-WAVE FREQUENCIES

The development of a new Heterojunction Bipolar Transistor (HBT) distr ibuted electrical model suitable for millimeter-wave applications is r eported, Each section of the distributed model is composed of an activ e slice, modeled as an intrinsic HBT, and connected to other slices th rough a passive connecting network, It is shown that, for large size a nd high power HBT's, a distributed model is more accurate than a lumpe d-element one, This is confirmed by comparing the S-parameters calcula ted using both models to the measured data over a wide frequency band, It is also shown that the distributed model allows accurate predictio n of S-parameter behavior at higher frequencies where the lumped model may not have accurate prediction.