Low Magnetic Field Of The X-band High-power Backward Wave Oscillator

A coaxial relativistic back-wave oscillator (RBWO) with inner sinusoidal corrugated conductor is investigated in this dissertation. The dispersion equations of the slow-wave structure are derived, calculated and discussed in detail. The coupled impedance of the SWS is derived and calculated. The RBWO with inner sinusoidal corrugated conductor is simulated and optimised with a PIC code. The factors effecting the output power and efficiency of the RBWO with inner sinusoidal corrugated conductor are discussed. Some ways improving the output power and efficiency are suggested. The characteristic of the coaxial reflector is investigated.The RBWO with inner sinusoidal corrugated conductor has some unique advantages: The existing of inner coaxial structure can largely increase the cutoff frequency of the system, thus allowing a larger size of SWS. The power capacity is much improved. The mode competition is much improved. It may operated with a large electron beam radius, that means decreasing the space charge effects compared with a smaller radius beam with the same current, hence the RBWO may operated with a low axial guide magnetic field. Besides, the RBWO with a sinusoidal corrugated coaxial structure is very easy to manufacture. It is a kind of promising high power microwave device.