Study Of High Frequency Structure For High Power Gyrotron

Gyrotron has a history of about 40 years, its’ appearance has made up for the absence of the high-power devices which works in the frequency of millimeter wave and submillimeter wave. Because the frequency of millimeter wave is between 30 GHz and 3000 GHz, so it has the important features of short wave length and a better bandwidth. For the feature of short wave length, it’s impossible to make it having a high resolution and high goal accuracy, hence it can effectively improve the concealment of weapons systems and anti-interference ability. Besides, a better bandwidth can be applied in radar systems and communication systems.However, a smaller cavity machining dimension has become a difficult problem with the development of gyrotron. In order to avoid this problem, a higher operating mode must be selected. But a higher operating mode is bound to bring a lot of competition modes. Therefore, it’s important to effectively select the best operating mode and inhibit competition modes. Based on the linear theory of gyrotron, nonlinear theory and coupled wave theory, a gradient cavity of gyrotron has been designed which can effectively operate at TE22,6 mode in the frequency of 95 GHz, and a detail analysis has been made. In the end, ideal structure parameters and working parameters can be got. This provides a good theoretical reference for the future project. The main contents of this paper are as follows:1. Based on the linear theory, firstly, the dispersion equation, the coupling coefficient, the start-up current can respectively be derived. Then, in the fourth chapter,according to the coupled wave theory and the above derivation, the high frequency structure of 95 GHz gyrotron can be designed, and a series of detailed analysis have been made for the high frequency structure parameters. Secondly, the dispersion equation, start-up current as well as the coupling coefficient can be obtained basing on the above derivation. This different parameters are important to the regular work of the gyrotron and offer guidance.2. To study the nonlinear theory of the gyrotron, the normalization process can be made for the equation of electron motion and the transmission line equation, then the computer simulation program can be obtained combining with the boundary conditions and beam-wave interaction efficiency. Thus, established the beam-wave interactionnumerical solution method.3. According to the established beam-wave interaction numerical solution method,to study the hot cavity operating at TE22,6 mode in the frequency of 95 GHz in the fifth chapter. Here, to analyze the influences of magnetic field, voltage, current, horizontal and vertical velocity ratio and guiding center radius on wave interaction efficiency.Then, basing on the principle of maximizing efficiency, the best working parameters can be got.