Temperature Reliability Investigation for a 400 W Solid-State Power Amplifier under High and Cold Conditions

In order to study the temperature reliability of high-power amplifiers under high cand cold conditions, a 400 W solid-state power amplifier was taken as an example to explore the variation in its performance. The test results showed that its output power, gain, and power-added efficiency increased with the increase in temperature at a fixed frequency. Under a fixed input power, Pout and gain both showed different trends with the rising temperature. Within the frequency band of 2–10 MHz, the higher the temperature, the better the output power and gain. However, within the frequency range of 10–30 MHz, the higher the temperature, the worse the performance. Moreover, with the increasing temperature, its power-added efficiency, the second harmonic and the third harmonic also showed a decreasing trend. Detailed analysis showed that the degradation and inversion of performance parameters are closely related to the zero temperature coefficient and self-heating effect of the lateral double-diffused metal–oxide–semiconductor field-effect transistor. Meanwhile, it is also affected by the circuit structure and thermal design of the PA. In order to ensure stable performance in different environments, performance degradation can be improved by hardware compensation. Therefore, analyzing the working parameters at different temperatures for high-power PAs is the key to achieving temperature control and ensuring their long-term stability and reliability. This can provide relatively accurate reference data for subsequent heat dissipation optimization, greatly improve design efficiency, and even shorten the development cycle and reduce costs.