Development of an S-Band High Average Power Multibeam Klystron With Bandwidth of 10%

An S-band high average power multibeam klystron (MBK) producing peak power of 500 kW and average power of 30 kW over 10% of relative simultaneous bandwidth has been designed and developed in Institute of Electronics, Chinese Academy of Sciences (IECAS). The biggest challenges were achieving over 10% relative simultaneous bandwidth performance with higher efficiency at the same time and focusing and transport of the intense electron beam because of the highest level average power in all types of MBKs in IECAS. Two prototypes were manufactured and both have been thoroughly tested. The fundamental mode was chosen for the RF interaction system, 24 beams are used to obtain a beam current of 50 A and the beam voltage is 29 kV. The efficiency is greater than 40% and the gain is greater than 37.5 dB over a relative simultaneous bandwidth of 10%. Both design considerations and experimental results have been addressed in this paper. The experimental results are close to design specifications.