Challenges of ALC in high power UHF SSPA for communication payloads

In a communication transponder the SSPAs have to deliver a stable output power in the desired dynamic range under all input conditions. Critically the output power must not exceed the safe input limit of the subsequent unit for reliable operation for which a feedback loop mechanism is explained. The paper presents a stable feedback loop functioning for a very tight protection limit close to normal output power under the self complexity of the loop itself and the Solid State Power Amplifiers Semi/Quasi-linear environment which poses a great challenge with respect to design and optimization of the feedback control mechanism. The paper also discusses the operating modes of the loop and its effect on the operational reliability.