Research On Helical Slow-Wave Structures Of High Efficiency TWTs

Traveling-wave Tube (TWT) is one of the most important types of the microwave/millimeter wave vacuum tubes. Due to its high power, high gain, high efficiency, and broadband, it is widely used in modern military electronic equipments, such as communications, radars, electron warfare, etc. The slow-wave structure (SWS) is the core of beam-wave interaction in TWT and it determine the performance of the TWT directly.In this dissertation, numerical simulation is conducted to fulfill a comprehensive analysis of the effects caused by different shapes, different materials and different geometrical parameters of the support rods of the helical SWS on the TWT high-frequency characteristics. The dispersion and interaction impedance of helical SWS are measured in an experiment. Excellent agreement is achieved between the experimental data and numerical simulation results, and this can provide reliable input for high efficiency large-signal analyses. A 1-D nonlinear beam-wave interaction TWT code is used to analyze and optimize helical SWS with a pitch tapering. As a result, electronic efficiency can be enhanced by the method of dynamic velocity tapering and it's extremely important for the design of the helical SWS of space TWT. The main achievements of this dissertation can be concluded as follows:1. Software package CST MWS, which is based on Finite Integration Technique, and TWTCAD, which is based on analytical theory, are adopted to investigate the effects of support rods' different shapes, materials...