This paper presents the simulation study of a C-band 50 MW klystron with disc-loaded waveguide traveling wave output structure. The electron gun with a perveance of 1. 53 μP is designed. The gun has a voltage gradient lower than 22. 1 kV/ mm and a cathode load current lower than 6. 3 A/cm2. The beam focusing system is a space-charge balanced flow type with solenoid magnet structure and the focusing beam trajectories have a good laminar condition. A single gap cavity is adopted instead of the traveling wave output structure in the initial beam-wave interaction simulation to decide the parameters of the cavities except the output structure. A C-band disc-loaded waveguide output structure working at π/2 mode is designed and the dispersion and interaction impedance of the structure are determined by the CST code. The beam-wave interaction system with disc-loaded waveguide output structure is simulated by a three-dimensional PIC code. More than 50 MW output power is obtained. The efficiency is more than 45% and the saturate gain is more than 50 dB. The voltage gradient of the disc-loaded waveguide output structure is 30 percent less than that of the single gap cavity and there is an increase of 4% in efficiency above that of the single gap cavity.%设计了导流系数1.53μP的电子枪,枪内场强低于22.1kV/mm,阴极平均负载小于6.3 A/cm2；采用部分屏蔽流均匀场电磁聚焦系统,实现了对电子注的良好聚焦；设计了C波段π/2模盘荷波导行波输出结构,采用CST软件对其色散特性、耦合阻抗进行了计算分析.首先以单间隙输出腔代替行波输出结构对5腔注-波互作用系统进行计算,确定了前4腔的设计参数,然后采用PIC模拟软件对具有盘荷波导结构的输出系统进行了三维模拟,获得了大于50 MW的输出功率,效率大于45％,饱和增益大于50 dB,盘荷波导结构间隙电压比单间隙输出腔下降30％,效率提高4％.
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