Reflection power suppression for solid state amplifiers with combiner optimization

The application of high-power solid state amplifiers (SSAs) in accelerator facilities is increasing, and equipment failure caused by reflected power is the main risk to their long-term operation. High-power SSAs often comprise multiple power amplifier modules. Full power reflection is more likely to damage the modules in SSAs if the amplitudes of the modules are unequal. Optimization of the power combiners is an effective means for improving the stability of SSAs under high power reflection. This study analyzes the mechanisms and conditions of reflected power generation using the scattering parameters of the combiner and proposes an optimization scheme for the combiner. The simulation and experimental results show that some modules may receive reflected power as high as nearly four times the rated power of one module when the SSA meets certain conditions, which could damage the modules. The maximum reflected power can be effectively reduced and the anti-reflection ability of SSAs can be improved by optimizing the combiner parameters to suppress the maximum reflected power.