Inner Slotted Coaxial Backward Wave Characteristics Theoretical Research

Relativistic back wave oscillator(RBWO)with a coaxial structure has a big power capacity of system. With large radius electron beam to decrease the space charge effects without usage of high current, hence the RBWO can work well at a lower axial guide magnetic field. Besides, the electromagnetic field distribution promotes effective interaction between electron beam and the electromagnetic wave, and only thousands of gauss of guide magnetic field are needed. So RBWO with a coaxial structure is kind of promising vacuum high power device.It is found that there is a competition among the modes such as TM₀₁, TM₁₁ and TM₂₁ because of their similar work frequency in the experiment of RBWO with a coaxial structure, then TM₀₁ mode couldn't work steadily. After shaping rectangular slot in the inner-conductor, the space between modes is enlarged, TM₀₁ mode would work steadily.Thus the theory study based on experimental result are as the following:1.The coaxial inner slotted structure waveguide is simulated and analyzed numerically, the change of the work frequency and space between work modes of coaxial structure is studied with the inner slotted. The parameters like the number and the depth of the inner slotted are optimized. It is found that the work frequency is decreased but the space between work modes is enlarged a little with the inner slotted in RBWO with coaxial structure.2. RBWO with partial inner slotted structure is designed and simulated, it is found that the work frequency is decreased and the space among modes is enlarged well with the inner slotted in RBWO with partial structure.3. A linear theory of RBWO with inner-slot coaxial structure is analyzed detailedly, and the equation of dispersive relation is deduced and computered numerically.4.Particle simulation is used in RBWO respective with coaxial and partial structure. In the simulation, the output parameters of RBWO such as phasespace, contour, vector, voltage , current, output power, interaction efficiency and microwave radiation...