设计了一种工作在W波段的振荡器。采用宽高比值为2的薄矩形电子注降低空间电荷效应，周期耦合腔慢波线作为高频结构以增加功率容量，阶梯渐变矩形波导作为输出结构，使输出结构与高频结构匹配连接减少反射。利用三维PIC粒子模拟程序进行数值模拟，分析慢波结构的周期数及周期长度对输出功率、频率及效率的影响。结果表明: 当阴极电压为13.0~16.1 kV时，谐振腔能正常工作; 谐振腔周期数为9，阴极电压为15.7 kV时输出功率和转换效率最大，输出峰值功率大于1.9 kW，平均功率为980 W，频率为91.6 GHz，转换效率达25%，输出频率随谐振腔周期长度的减小而增大。

A kind of W-band oscillator is designed. To reduce space charge effects, a thin rectangular sheet electron beam with a width-to-height ratio of 2 is adopted. In order to increase power capacity of the cavity, the periodic coupling cavity slow wave line is selected as the high frequency structure. And the ladder gradient rectangular waveguide is used as the output structure that can make the output structure and high frequency structure match well. The 3D-PIC simulation program is utilized to analyze the effect of the cycle number and length of the slow wave structure on conversion efficiency. The simulation results show that, when the cathode voltage is 13.0-16.1 kV, the high frequency structure can work normally, and when the cycle number is 9, the cathode voltage is 15.7 kV, the output power and conversion efficiency are highest, with the output peak power more than 1.9 kW, the average power of 980 W, the work frequency of 91.6 GHz, and the conversion efficiency of 25%. With the periodic coupling cavity length increasing, the work frequency decreases.