A Millimeter-Wave InP DHBT Multi-finger Modeling Approach Using Electromagnetic Simulation and Nonlinear Thermal Coupling Network
29 June 2017
large-signal modeling approach has been developed for multi-finger devices fabricated in an Indium Phosphide (InP) Double Heterojunction Bipolar Transistor (DHBT) process. The approach utilizes single-finger device models embedded in a multi-port distributed network. The single-finger model is based on an improved UCSD HBT model formulation avoiding an erroneous RciCbci transit-time contribution from the intrinsic collector region as found in other III-V based HBT models. The mutual heating between fingers is modeled by a nonlinear thermal coupling network with parameters extracted from electro-thermal simulations. For verification of the multi-finger modeling approach comparison with load-pull data measured at 30 GHz have been performed. Furthermore, the multi-finger modeling approach is verified against measurements on an 84 GHz power amplifier utilizing four finger InP DHBTs in a stacked configuration.
