Design and development of efficient and compact 20 kW 325 MHz solid-state amplifier for superconducting accelerator applications.

This article focuses on the design, development, and experimental validation of a compact and efficient 20 kW solid-state power amplifier (SSA) operating at 325 MHz, developed using 24 one-kilowatt power amplifier (PA) modules combined via a 24-way Wilkinson power combiner and divider. The SSA achieves an AC to RF efficiency of 54.8% at 20 kW output power, closely matching theoretical estimates, and demonstrates a power density of 12.7 kW/m³. Monte Carlo simulations based on measured gain and phase variations of PA modules indicate that the overall combining efficiency exceeds 92.6% with 90% confidence, and the amplifier maintains output power with graceful degradation when up to two PA modules fail. The amplifier supports both continuous wave and pulsed operation, exhibits harmonic content below −40 dBc, and features water-cooled PA modules and modular DC power supplies to enhance reliability and maintainability.