X-band Five-cavity Transit-time Tube Oscillator Theory And Experimental Research,

This dissertation is mainly concerned about the theoretical and experimental research of a npvel high-power microwave device of the X-band five-unit Transit-time Tube Oscillator (TTTO), which is based on the transit-time effect.Firstly, the structure model of this kind of oscillator is put forward. Resorting to the method of the finite-unit differential of time domain, the Maxwell equations are solved. Then the frequency of the eigen-modes and its distribution of E-field in the cavities are investigated.Secondly, resorting to the model of the single particle and the equation of movement, a pair of nonlinear equation is got by coordinate transformation. The equations are about the interaction of the transit-time effect between the beam and the wave. Then putting the distribution of E-field into the equations, the equations are solved. And the net energy exchange between the electrons and the field of different modes are put out. The one-dimension nonlinear analysis shows that the X-band five-unit TTTO can generate high power microwave.Thirdly, the X-band five-unit TTTO is simulated, by using the 2.5-D PIC code. It proves that the conclusion of the 1-D nonlinear analysis is right. Then combining with the 1-D nonlinear analysis and the high-frequency character analysis, the X-band five-unit TTTO is optimized and designed. It can generate the microwave of about 1GW of peak power with 22% of efficiency at 9.3GHz.In the last part of this dissertation, the experimental research is conducted on the accelerator of SINUS-700. The impedance transition is designed so as to test the proportion of standing wave for the support poles and modes transformer. After a series of adjustment, employing an annular electron beam of 700KV, 7KA and 40ns duration, the microwave of over 780MW of peak power with 21ns of duration and 16% of efficiency at 9.25GHz, can be generated.