An Electrothermal Model of High Power HBTs for High Efficiency L/S Band Amplifiers

This paper deals with an electrothermal model of high power heterojunction bipolar transistor (HBT) intended for CAD. The first section describes the model topology and sets the implemented equations that allow to take into account of the physical phenomena. The model also integrates scaling rules function of emitter length (W) and number of fingers (N). For the thermal aspect, low frequency impedance measurement approach has been led. Model simulations have been compared to quasi-isothermal I-V measurements, pulsed S parameters measurements, and load-pull multi-harmonics measurements.