The Research On Mode Converter And Cold Test Of Gyrotron

As the development of military and scientific research, the demands of microwavesources with the characteristics of higher power, higher frequency and higher energy aremore and more urgent, under this background, the high power microwave technologyhas developed rapidly. It is widely applied in military equipment, scientific research,new material preparing, medical, biology and other fields.As a new kind of millimeter wave devices, gyrotron traveling wave tube hasattracted wide attention, due to its high peak power, high average power, high gain, highefficiency and other advantages. And it also used to be the power source ofcommunication, electronic countermeasure and millimeter wave radar system.High power microwave system generally includes the following parts: inputcoupling resonator system, transmission system, the output coupling system, modeconversion system, antenna transmitting and receiving system. The performance of eachsubsystem plays an important role in the high power microwave system. In microwavetransmission and emission process, mode conversion can make the energy of highpower microwave source transmiss and radiate more efficiently. So it has a veryimportant value of research and application. In order to shorting the period of the design,cold test was adopted to acknowledge the performance of those subsystems, find itsdisadvantage and revise some part of contracture timely. Based on the importance ofmode conversion, this paper has included a lot of theoretical study and Simulation ofTE01-TE11-HE11. The TE01-TE11mode converter has been designed and machined,validated by experiment, and has been successfully applied to the research of our lab.Otherwise, this paper research theory about the input coupler, output windows anddielectric loading of gyrotron.The main work of this thesis is as follows:1. The development of high power microwave technology and gyrotron travelingwave tube is systematically discussed, and the status, methods, progress of high powermicrowave transmission system and mode converter technology was studied deeply.2. Research the model transformation chain by TE11as the intermediate mode; deduce the coupled wave equation and the coupling coefficient of axis bending modeconverter by the coupled wave theory; explore the transformation of axis bending modeconverter in detail; put forward some methods for improving the conversion efficiency.3. Optimize the axis bending mode converter numerically using the four orderRunge-Kutta method and phase rematch; show the optimization results for the Q bandand W band; conclude the relationship between length and bandwidth and conversionefficiency of mode converter. Based on the Q band mode converter were analyzed anderror, summarize that the effects of small changes in structural parameters and length onthe conversion efficiency is very small, but small changes in the radius of the modeconverter has the opposite effect on the conversion efficiency effects.4. This paper expose the develop procedure of TE11-HE11mode conversion indetail. According the theory, the fifth chapter analyses the merit and demerit betweencorrugated circular waveguides and horn with gradient radius preparing the fundamentfor next research.5. Discussing the cold test systematically, this paper gives effect and the mainparameters of input, output and dielectric loading in gyrotron and the testing theory.After that we design a testing platform and contrast the testing results with thesimulation results.