| With the wide application of high power microwave technology at the high-frequency(above X-band), and in order to adapt to the development trend of low impedance pulse power source,the thesis puts forward the power synthesis of the miniaturization of more devices to easily inhibit self-excited oscillation in the same system. The most high-gain relativistic klystrons work on the off-axis in the above technical solution, so it is necessary to carry out the research of its’ off-axis property, and the analysis of the power synthesis technology of sigle ystem of off-axis more devices.Firstly, the equivalent circuit theory of RKA’s various cavities and the beam bunching mechanism in the drift tube is studied based on the operational features of the intense beam RKA. And in order to explain the electron beam’s deflection in the off-axis high-gain relativistic klystron, the paper analyzed that the deflection of of the electron beam is identical with the offset of the magnetic field lines of its cyclotron center in theory after studying the off-axis’ s magnetic field properties of solenoid coil.The off-axis’ s annular electron beam is bunched in the middle of the area in the middle of the off-axis’ s bunching magnetic field, and this result of the theoretical analysis is validated by PIC particle simulation.Secondly,an X-band high impedance’s(800 ohm) five-cavity high-gain RKA is designed based on that the self-oscillation caused by the reflux of electron can be suppressed by reducing the beam intensity and the gain of drive can be improved by increasing the number of the middle cavity. And for purpose of reducing the probability of breakdown of the rf, the slow-wave structure’s output cavity is adopted above the designed device, finally its output power reaches 300 MW in whole tube’s 2D simulation, and the gain and efficiency are of 50.3 dB and of 37.5 % respectively when the input microwave power is of 2.77 kW, and the beam voltage and beam current is of 800 kV and of 1.0 kA. For excluding the interaction of the axisymmetric mode, the whole tube 3D model of the device is studied in this paper. The axisymmetric mode’s interference of device is suppressed by adjusting the size of the input cavity and the length of the first drift tube, finally its output power reaches 284 MW in whole tube’s 3D simulation, and the gain and efficiency are of 51.6 dB and of 35.5 % respectively with input microwave power of 1.96 kW. To study the off-axis property of the high-gain RKA, the results prove that the microwave power can be also amplified by the off-axis’ s device, and its stabilized microwave output power reaches 282 MW when the ff-axis radius is of 54 mm in the middle area of the magnetic fieldFinally, the thesis developed a series of research of power- combining techniques of the single system of eight devices been equally placed the circle of 54 mm of off-axis radius in the same magnet. Then an eight to one power combiner is designed using HFSS software, and the combiner with eight-tube high-gain RKAs is simulated by a three-dimensional model. Its output power is 1.84 GW, with a gain of 50.7 dB and efficiency of 28.9 % respectively. |
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