Abstract

This paper describes novel techniques for the implementation of a practical large-signal HBT model into the popular commercial microwave CAD package, Libra™. These techniques are applied to a modified Gummel-Poon (GP) SPICE HBT model described in [1]. The model takes into account the well known self-heating and transit-time effects present in HBTs [1-5]. In particular, the excess phase factor (PTF) has been added to the built-in GP model of Libra™ (Series IV, V. 6.0) using an ideal delay. Furthermore, only built-in linear and nonlinear Libra™ elements are utilized to account for various physical phenomena described by the model. Simulated and measured results are compared for a 6.5x3um2 GaInP/GaAs HBT under DC, small-signal from 1 to 40GHz, and large-signal conditions at 12GHz in order to assess the accuracy of the model.