Thermal Burnout Effect of a GaAs PHEMT LNA Caused by Repetitive Microwave Pulses

The thermal burnout effect of a gallium arsenide (GaAs) pseudomorphic high electron mobility transistor (PHEMT) low-noise amplifier (LNA) caused by repetitive microwave pulses is studied by theoretical analyses, simulations, and experiments. The theoretical model for thermal burnout under a single microwave pulse injection is first acquired by analyzing the power absorption in the electrical procedure and the heat distribution in the thermal procedure. By adopting two new assumptions and using the linear superposition theorem, the theoretical model for thermal burnout under a repetitive microwave pulse injection is acquired by further extension. Through derivation, the analytical relationship among the thermal burnout power threshold, the pulsewidth in a cycle, the pulse repetition frequency (PRF) and the pulse number is acquired. Because some assumptions and approximations are adopted, both the pulsewidth in a cycle and the total repetitive microwave pulselength must be between 10-ns scale and 1-μs scale. It shows that the theoretical results agree well with the simulation and experimental results. A minimum of two sets of data by experiment or simulation are needed to fit the analytical relationship. Therefore, experimental or simulation costs can be substantially reduced, and a helpful reference for