In this article, a compact mode selection filter and a mode converter for the 0.22-THz sheet beam traveling-wave tube (SB-TWT) has been proposed, fabricated, and tested to realize selective absorption of high-order mode without interference on the working mode. The reasonable structure and placement is explored from theory to manufacturing method in order to minimize reflection and mode distortion by junction discontinuity. Two proof-of-concept prototypes have been fabricated and tested to analyze the error sources in terahertz device. And the corresponding error models are also constructed. Final transmission data exhibit an excellent agreement with the results of computer simulations when conductor loss is taken into consideration. Such −15-dB loss performance for high-order mode is verified allowing to cover the frequency band from 0.3 to 0.315 THz.

中文翻译：

---

亚太赫兹片束行波管紧凑型模式选择滤波器的设计、微加工和实验


本文提出、制造并测试了一种用于 0.22 THz 片束行波管 (SB-TWT) 的紧凑型模式选择滤波器和模式转换器，以实现高阶模式的选择性吸收而不干扰工作模式。从理论到制造方法都探索了合理的结构和布局，以最大限度地减少结不连续引起的反射和模式失真。已经制造并测试了两个概念验证原型，以分析太赫兹设备中的误差源。并构建了相应的误差模型。当考虑导体损耗时，最终的传输数据与计算机模拟的结果非常吻合。这种高阶模式的 −15dB 损耗性能经过验证，可覆盖 0.3 至 0.315 THz 的频段。