Effect of plasma and dielectric loading on the slow-wave properties of a traveling-wave tube

Abstract

The slow-wave dispersive properties of a traveling-wave tube (TWT) changes considerably when either the helix is supported by a dielectric or the waveguide is filled with plasma. The dispersive properties of the dielectric-supported helix waveguide have been examined for different geometric parameters of the helix waveguide. The dispersion relation of the helix mode is found to be upshifted by a>p cos 2 <j>, when plasma is introduced in the device, where u P , <j> are the electron plasma frequency and the pitch angle of the helix respectively.