TWT Three-Dimensional Nonlinear Theory And Its Network Parallel Computing

Traveling wave Tubes (TWT) are high gain, broadband, high efficiency, high power microwave/millimeterwave amplifiers, which are widely used in modern military electronic equipments, such as communications, radars, electronic warfare, etc. In this dissertation, we have made detail study on TWT three-dimensional nonlinear beam-wave interaction and its network parellel computing. Several important and valuable results which bring forth new ideas are achieved and listed as the followings:1. The uniform self-consistent working equations of interaction between slow electromagnetic traveling wave and electron beam have been obtain, using the theory of mode expansion. The equations include excited equation, motion equation, energy conversion equation, phase evolving equation, etc. which can simulate the beam-wave interaction process in relativistic TWT and multi-signal multi-mode TWT.2. The space-charge fields of nonlinear beam-wave interaction in TWT have been studied using the finite-size macro particles. The weight functions of finite-size macro particle space-charge fields have been obtained. The results show that: in long distance, the weight functions of finite-size macro particle space-charge fields are agree well with those of ring-mode space-charge fields. But in short distance, the weight functions of finite-size macro particle space-charge fields are smaller than those of ring-mode macro particle space-charge fields. So the simulated saturated position is shorter and the simulated saturated output power is larger.3. Based on the TCP/IP, the network parellel computing environment, which is simulated the TWT three-dimensional nonlinear beam-wave interaction process, has been built. The programs hav been programmed, which can run in computer network composed of workstations and microcomputers. The experiment results show that: the network parellel computing environment can effectively reduce the simulating time of TWT nonlinear beam-wave interaction and improve the work efficiency.4. The TWT multi-signal nonlinear characteristics, as the case of two signals input, have been studied. The results show that: when two signals are inputted into TWT, the output power includes the intermodulation components, and the intermodulation components have important effect on broadband TWT.5. The relativistic TWT three-dimensional nonlinear characteristics are also been studied. The results show that: (1) The space-charge fields(include dc space-charge fields and ac space-charge fields) have important effect on the beam-wave interaction output power, make the saturated output power lower, saturated position delay; (2) The back-radio excited by the electron beam has little effect on the output power, and can be ignored; (3) The transverse motions of electron beam has some effect of the output power; (4) The means of phase velocity taped and bunch compression can improve the relativistic TWT efficiency, especially bunch compression can greatly improve the efficiency. In this dissertation, the effects of input power, electron beam voltage, electron beam current and focusing magnetic field on output power have been studied. The output results of four slow-wave structures designed have been compared, the adaptive interaction parameters have been designed.6. A means, which can measure the TWT multi-signal nonlinear characteristics, has been designed. We have measured the multi-signal nonlinear characteristics of a tube, the measure results show that: When two independent signals are synchronously inputted into the tube, the output power includes the intermodulation signals. The measure results are agreement well with the simulated results.