Design Method of the Non-Periodic Meander Line and Folded-Waveguide SWS for TWTs Based on the Effective Phase Velocity Synchronization

A design method of the non-periodic meander line slow-wave structure (ML-SWS) and folded-waveguide slow-wave structure (FW-SWS) for traveling-wave tubes (TWTs) is proposed based on effective phase velocity synchronization. For the non-periodic ML-SWS and FW-SWS, the unified effective axial phase velocity seen by electrons, the dispersion equation, and the ideal beam-wave synchronization voltage are derived. The theoretical results demonstrate that the non-periodic ML-SWS and FW-SWS reported to date are consistent with the proposed method. Furthermore, two examples are presented as applications for the proposed method to the non-periodic SWS design, including the concentric arc FW-SWS and the zigzag ML-SWS. In addition, the simulated results of the two examples are in good agreement with the theoretical ones.