Enhancing Broadband Helix TWT Performance Using Hollow Electron Beam

This article presents a study on the utilization of annular beams in broadband helix traveling wave tubes (HTWTs). The research delves into the beam-wave interaction (BWI) performance of HTWTs under different hollow electron beam conditions. The theoretical analysis includes the use of gain parameter $C$ and space charge parameter $QC$ to evaluate the performance within the linear interaction region. Based on the analysis, a 4–20 GHz ultra-wideband traveling wave tube (TWT) based on a hollow beam scheme was designed using the software microwave tube simulator suite (MTSS). The design process involved optimizing the slow wave structure (SWS), the BWI performance, the electron gun, and the magnetic system. An output power greater than 109 W is achieved, and the small signal gain is better than 23 dB across the entire operating bandwidth. The particle-in-cell (PIC) solver in CST was used to verify the saturated gain of the designed TWT.