High Frequency Characteristics Of Tortuous New Slot Waveguide Slow-wave Structure

As a low noise, broadband, high power and high gain microwave vacuum tubes, Traveling Wave Tubes (TWTs) have been widely used in military radars, satellite communications and electronic confrontations, which play an important role in modern electronic equipments. The slow-wave structure (SWS), as a key part of TWT where the beam-wave interaction carries out for exciting microwave energy, determines its performance directly. With the development of techniques, novel slow-wave structures are needed to improve the performance of TWT with higher power and wider bandwidth. In this paper, a novel folded groove waveguide slow-wave structure is proposed with the foundation of folded waveguide and grooved guide. High frequency characteristics of such SWS are also analyzed in this paper. The main works are listed as follows:1. The development history, present research situation of TWTs and SWS are introduced in the first part. As a kind of all-metal SWS, the serpentine waveguide has been investigated thoroughly. When worked in high frequency, folded waveguide SWS still shows some problems, i.e., hardly fabrication and higher ohmic loss. In this situation, folded groove guide SWS is proposed and studied in this dissertation.2. The research methods of serpentine waveguide and groove guide have been introduced. Eigen equation of rectangular groove guide is obtained by Galerkin boundary integration equation method. More accurate results are got with four-order approximation, which show good convergence and better agreement with experimental data when compared with previously published papers.3. The dispersion characteristics and interaction impedance of the groove guide SWS are analyzed theoretically in detail. By use of MATLAB, numerical programs are compiled to get dispersion curves and impedance diagrams. The influence of geometrical dimensions on the dispersion characteristics and interaction impedance are discussed.4. As an assistant analysis, CST MICROWAVE STUDIO is applied to simulate dispersion characteristics and interaction impedance of rectangular groove guide. Simulation show better agreement with theoretical results.