新型反绕双螺旋线慢波系统的分析与设计

 基于降低工艺难度的目的，提出了一种新型反绕双螺旋线慢波系统，该系统的正绕反绕螺旋线半径不等。利用3维电磁软件CST MWS仿真分析了结构参数对色散和耦合阻抗的影响。结果表明：耦合阻抗在螺旋带内半径较大时没有明显下降；减小螺旋带宽度有利于降低相速度和提高耦合阻抗；在一定范围内，相速度随螺距的减小而增大。在此基础上，结合工程要求设计了8 mm波段行波管的新型反绕双螺旋线慢波系统，耦合阻抗达到21 Ω，工作电压约为20 kV，同时由于电子通道半径较大，降低了对电子光学系统的要求；纵向翼片加载的引进较为有效地展宽了带宽。

Analysis and design of novel contrawound helix slow-wave system

In order to overcome the difficulties of manufacturing, a novel contrawound helix slow wave system is presented. The 3D soft CST MWS is used to simulate and investigate the influence of dimension parameters on the system’s dispersion and interaction impedance. The results show that the radius of contrawound helix can be larger than that of helical without causing a sharp decrease of interaction impedance and the decrease of tape width helps bring down the phase velocity and improve the interaction impedance.The results also indicate that in certain range,the reduction of pitch increases the phase velocity. A novel contrawound helix system is designed for 8 mm millimeter wave TWT, the interaction impedance is over 21 Ω, and the operation voltage is about 20 kV. It has a low requirement