The input/output microwave circuit of a W-band gyrotron traveling-wave tube (gyro-TWT) with a predicted output pulse power of more than 300 kW and a bandwidth of about 8% is under investigation. A distinctive feature of this circuit is the transverse (relative to the axial velocity of the electrons in the gyro-TWT) extraction of the output power and its compatibility for feeding and coupling the microwaves out through one oversized barrier window. The whole circuit consists of components inside and outside the tube vacuum volume. The key elements of the inner circuit are a waveguide mode converter forming the ring-like distribution of the radiation from the incoming TE _1,1 mode and a 45° inclined mirror with a hole enabling a lossless transport of the gyro-TWT electron beam to the collector. Aluminum prototypes of these components have been fabricated and cold-tested in the frequency range of 90–102 GHz. The measured 2D mode patterns and level of the cross-polarization are found to be in good agreement with the simulations.

中文翻译：

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大功率W波段陀螺TWT的横向输入输出微波电路组件的冷测试

正在研究预测输出脉冲功率超过300 kW，带宽约8％的W波段回旋行波管（gyro-TWT）的输入/输出微波电路。该电路的显着特征是输出功率的横向提取（相对于陀螺仪TWT中电子的轴向速度）及其与通过一个超大屏障窗口馈送和耦合微波的兼容性。整个回路由真空管内外的部件组成。内部电路的关键元件是波导模式转换器，其形成了来自传入TE _1,1的辐射的环形分布 模式和带孔的45°倾斜镜可将陀螺TWT电子束无损传输到收集器。这些组件的铝制原型已经在90–102 GHz的频率范围内进行了制造和冷测试。发现测得的2D模式图案和交叉极化水平与仿真非常吻合。