Reflector

This dissertation mainly focuses on 8 millimeter wave band open reflectors in high-power microwave devices. The main job is the following:1. Mode-matching technique is applied to analyze scattering from single-step structure, and the theoretical results are compared with the simulation ones. The reflection of TM0n mode from a resonator is investigated. A multi-stage resonator is analyzed, and studied by Computer Simulation Technology, then compared with the single resonator. Finally, the resonator with a tapered smooth-wall waveguide is presented, and the position of the resonator and the length of the tapered waveguide are optimized.2. Secondly, to enhance the reflection, Bragg reflector is investigated. The study is focused on the Bragg reflectors composed of cylindrically symmetric sinusoidal corrugations. The reflection of TM_On mode from Bragg reflector is studied in detail by theory, and three important parameters such as corrugation amplitude, periodic length and the number of periods are discussed carefully too. Our study shows that the reflection and bandwidth can be improved by sinusoidal Bragg reflector. At last, this paper analyzes a tapered sinusoidal corrugation reflector and has given some useful results through numerical simulation.3. After that, trianguIar and rectangular Bragg reflectors are analyzed. These two kinds of Bragg reflectors are investigated in detail by CST MICROWAVE STUDIO, and the effects of the corrugation amplitude, periodic length and length of reflector to the reflection are also investigated. Finally, some comparison and analysis of these three kinds of Bragg reflectors are given in this paper.4. Furthermore, three kinds of Bragg resonator cavities with two corrugation sections separated by a smooth section are analyzed and simulated.The research indicates that a single resonator cannot meet the request of high reflection and good bandwidth in high-power microwave devices, however, Bragg reflectors and tapered structures can achieve that purpose. Thus, the output power of high-power microwave devices can be improved efficiently by choosing right shape and size of reflectors. The research is valuable to the development of high-power microwave devices in our country.