Traveling-wave Tube Multi-stage Depressed Collector Support Cad And Its Secondary Electrons

The traveling wave tube (TWT) is an important high-power microwave resource, which has been applied in many fields such as radar, broadcasting, high-power microwave weapon and so on. In TWT, RF field extracts energy from the electron beam. The electron beam must interact with the traveling wave field at the approximate speed, so that the electronic efficiency is much lower. The multistage depressed collector (MDC) is an important method of improving the TWT efficiency. Simulating the electronic devices by computers, can make the design cost effective and reduce the repetition in the fabrication process.The scope of this is concerned with the study and simulation of MDCs to improve the efficiency. A MDC with a refocusing system is simulated with the help of a 2.5-dimensional(2.5-D) software, in which the secondary electrons are considered. These jobs offer a guarantee for the improvement of the tube efficiency.The organization of this paper is as follows.Chapter 1 introduces TWT and the development of TWT. The MDC is also introduced. The methods are provided to improve the efficiency of TWT. These research level and new simulation software for MDC are described.In chapter 2, the principles of MDC for TWTs, refocusing and the influence of the secondary electrons are analyzed. The electron energy entering the collector is analyzed. The conception of collector efficiency is defined.Chapter 3 describes the equations concerned with the simulation of MDC. The 2-D axial-symmetric MDC is studied, so the equations can been simplified to 2-D problems. The key problem of the calculation of the equation of the electronic motion is illustrated. The numerical computing methods of the equations involving the static electric-magnetic field, electronic motion in the static electric-magnetic field, and so on are detailed. The methods of the boundary disposal are introduced. The phenomenon of secondary electron emission has also been studied. The secondary electron effect is incorporated into the simulation, which are divided into true secondary and reflected primary electrons.