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