High power SiC solid state RF-modules

Solid state amplifiers begin to replace traditional vacuum tube technology (e. g. Klystrons) in several accelerator applications [1]. They offer the perspective of lower cost, better reliability and reduced maintenance [2]. Due to their modular construction, power levels can be scaled easily to meet the target application requirements. The new direct drive concept [3] offers the benefit of simple triggering and the possibility to individually control phase and power in each cavity segment, which increases operation mode flexibility of the final particle accelerator. We present development results of compact high power solid state RF-modules based on novel SiC transistors. The SiC transistor layout and the packaging technology was optimized for high frequency operation and we already reported previously that SiC transistors can provide RF output power levels well above 1 kW per device at 150 MHz [4]. We now present our second generation of high power solid state RF modules based on normally-on SiC vertical JFETs with significantly increased power ratings in the range of 5 - 25 kW per module depending on supply voltage, input power and pulse duration. An 84 kW RF-source was built by power combining of 32 RF-modules running at relatively low voltage of 160 V.