28-V low thermal-impedance HBT with 20-W CW output power

Model order reduction of linear and nonlinear 3D thermal finite-element description of microwave devices for circuit analysis

“…Thus, the risk of a hot spot in the emitter is reduced or can be mastered. Moreover, in order to improve the thermal resistance of the devices, many techniques can be applied, such as the use of a heat spreader to connect fingers [3], flip-chip mounting technology [4], or the use of thick copper or diamond materials on top of the emitter finger [5].…”