Measurement-base thermal circuit modeling of GaN HEMT

In this paper, we propose extraction of thermal circuit based on experimentally obtained transient temperature of GaN HEMT. Also, we evaluated the thermal circuit using randomly changed power, which simulated a modulated signal such as TDD-LTE. A thermal circuit was extracted using a simple pulse-shape dissipation power. The temperature was confirmed to begin to rise at 10–4 sec, showed a trend of saturation at around 10
^–2
sec, then began to rise again around 10
^–1
sec. For formulation of this temperature rise, we used a 5-stage thermal resistance and capacitance circuit. We have evaluated the extracted circuit model using randomly changed power with a frequency of 1 kHz. Both measured and simulated temperature are agreement with tracking the power change. Therefore, we can conclude our methodology may play an import role in RF operation under dynamically changing power conditions such as TDD-LTE.