Ka-band Whirl Backward Wave Tube

Gyrotron devices are irreplaceable for the application in millimeters band. We have developed many kinds of Gyrotron deveces these years. Gyro-TWT is one of the most mature device of them,but its stability is not so good, the backwave oscillation application is the biggest competive mode for the operating mode in Gyro-TWT,the backwave oscillation can seriously undermine the stability of Gyro-TWT, so how to supress the backwave oscillation is very important for Gyro-TWT. Meanwhile, the research of backwave oscillation is also necessary for Gyro-BWO, as it is the basic working mechanism for Gyro-BWO.Gyro-BWO has wide frequency bandwidth, and its working frequency can be continuous tuning. So it has a bright application prospect in the fields of material processing,microwave weapons, radar jammers etc. Conciderable interests have been raised regarding the development of Gyro-BWO.In this article,firstly we makes a comprehensive analysis for the backwave ocsillation in Gyro-TWT based on the liner theory, we also applied the theory to Gyro-BWO.then analysed the starting length and efficency of the Gyro-BWO using the unliner theory. The main content includes:First, giving a simple description for the electron cyclotron maser theory,it makes we understanding the physical process of the electron cyclotron maser in some extent.uesing the mode coupling theory, giving out a brief analisis for the operating pinciple for the Gyro-TWT and Gyro-BWO.initially identify some of the working parameters for the gyrotron.Second, giving a comprehensive research and reduction on the cyclotron linear theory which is based on the dynamical theory.that is analysing the interaction process by simultaneous the valsov and maxwell equation.then we can obtain the dispersion equation of the interacton process in gyrotron,and the amplitude expressions of the electronmagnetic. And the different boundary condition of Gyro-TWT and Gyro-BWO are given out too.Third, analysing the backwave oscillation in Gyro-TWT,based on the liner theory. figure out the possible backwave oscillation mode in the Gyro-TWT working in the kawave band. And the analysing their starting length and frequency, and finding out their changes with the operating current. We also discussed the way using the load loss material to suppress the backwave oscillation. Regarding to the Gyro-BWO, choosing a suitable working mode which can get a biggest coupling corefficient, the finding out the staring length and frequency of thie mode, and the impaction of the working current on them. Also conducted a preliminary discussion frequency tuning of the Gyro-BWO.Four, giving a comprehensive research and reduction on the cyclotron non-linear theory, and applied it on the Gyro-BWO whick working in the ka wave band,analyzing out its start length and frequency and their changing with the working current. At last we discussed the two different result that we gain from the two different theory.