Direct extraction method for internal equivalent circuit parameters of HBT small-signal hybrid-/spl pi/ model

We present a novel and robust direct extraction method for the hybrid-/spl pi/ equivalent circuit model of a HBT. This method can accurately resolve the most important internal parameters from the measured S-parameters, and is not sensitive to the values of parasitic parameters. We derive some analytical expressions for the parameters. These analytical expressions for the hybrid-/spl pi/ equivalent circuit of the HBT ensure robust, fast, and reliable parameter extraction.