Thermal model of high-power amplifiers based on time-dependent temperature profiles measured by photoconductance

We developed a theoretical model to fully describe the time-dependent thermal behavior of high-power amplifiers (HPA), considering all the main thermal resistances related to the junction/chip/package/heat sink interfaces. We also included thermal capacitances to fully describe transient behavior of time-dependent temperature profiles. Our thermal model allows the extraction of thermal resistance and thermal capacitance from observable variables, related to the time constants of experimentally measured temperature profiles, extracted in pulsed regime corresponding to different C- And X-band HPA based on GaAs and GaN technologies. Temperature profiles are extracted from time resolved photoconductance spectroscopy.