Compact Electrothermal Modeling of an X-band MMIC

Abstract — Compact electrothermal modeling of lumped electrical devices and compact thermal modeling of volu-metric materials enables efficient electrothermal modeling of microwave circuits. The compact thermal model of the body of an X-band MMIC is based on analytical solutions of the heat diffusion equation in thermal sub-volumes. The model is accurate and captures thermal nonlinearities. The model considers complex MMIC features such as surface metallization and vias, as well as the mounting configurations including lead-frame, carrier, and printed circuit board. This is coupled with electrothermal models of transistors and of resistors. The models are incorporated in a multi-physics simulator that uses the same model in both transient and harmonic analysis of an X-band LNA MMIC. Simulations are validated with steady-state thermal measurements. Index Terms — MMIC, electrothermal effects, circuit sim-ulation, modeling