| Terahertz is the electromagnetic waves that the frequency is between 0.1THz-10 THz,because of its broad prospects for development, was received universal attention by various countries, developing very rapidly. Because TeraHertz wave is between infrared and millimeter waves, it that has distinct advantages can be suitable for imaging technology、safety check、terahertz radar and so on. However, the key technology of the terahertz technology is to generate terahertz wave, so the development of high efficiency and high power terahertz wave source is the basis for the development of terahertz technology. Terahertz gyro-device in the highest output power radiation device of Terahertz frequency band, so vigorously develop terahertz gyro-device has become a hot topic.However, with the improvement of work frequency of terahertz device, the problem of size effect and power capacity is difficult to get a perfect solution. As a general rule, use high order mode to work can improve the output power, but high order mode often introduce mode competition. Particularly in the terahertz frequency band, the size of the device relative to Terahertz cyclotron is smaller than the ordinary microwave device, so its mode competition is more difficult to restrain. Therefore, to study a high-frequency interaction structure which can work at terahertz frequencies and solve the mode competition problem has become a priority.After a long-term exploration, different modes of quasi-optical waveguide which has diffraction loss has better mode selection feature. So we can use the quasi-optical waveguide structure interaction energy segment as a model to solve the issue of mode competition.The focus of gyrotron Research is to analysis its beam-wave interaction efficiency, because of the electron bunching and energy exchange is done in the beam-wave interaction, the study of their beam-wave interaction processes become the focus. Because the Processing and experimental of terahertz cyclotron is relatively complex, at the beginning of the research and development to numerical modeling studies has become a necessary process. At the support of teaching-research office projects, this thesis use independently developed three-dimensional particle simulation software CHIPIC to theoretical research and three-dimensional numerical simulation for 0.22 THz gyro-device. The details are as follows:1. to structural analysis and theoretical research for gyro-device of quasi-optical waveguide structure. Through in-depth study the Gaussian beam equations of quasi-optical cavity, to analyze the electromagnetic field distribution expression pattern. Secondly, to study the diffraction loss problem of quasi-optical waveguide. And to analyze the problem of mode competition, which can laid the foundation of quasi-optical waveguide as the middle Interaction chamber of gyrotron.2. To theoretical analysis the optical cavity cyclotron oscillator tubes, including the derivation of the kinetic theory of gyrotron research, the dispersion equation. And select the appropriate structure for the preliminary design; finally use the three-dimensional particle simulation software CHIPIC to numerical simulation. Analysis its operating characteristics, to study the related electrical parameters influence of work performance, it can be as a foundation preparation for the experiment of gyrotron amplifier lately.3. To analysis the operating principle of the Gyro-Backward wave oscillator, and to design a quasi-optical waveguide structure BWO which center frequency is at the roundabout 0.22 THz, and use the three-dimensional particle simulation software CHIPIC to optimization simulation, separate analysis the magnetic tunable and voltage tunable, optimizing structural parameters, finally get a cyclotron which meet the requirements of the power and frequency band.Finally, the gyro-TWT simulation experiments date are compared with simulation data consistent,the results is matched well, as a foundation preparation for the experiment of gyrotron amplifier lately. |
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