Millimeter-wave Quasi-optical Mode Conversion

Quasi-optical mode converter for high power millimeter wave sources, there is very important for applications. It is the hot area of researching cyclotron oscillation tube and usually consists of a Vlasov launcher and multi-level reflectors, its working mechanism is the use of waveguide cut ways to produce off-axis radiation and the Gaussian field distribution to fulfil system parameters requirements is obtained by the multi-level reflectors for focusing, phase-corrected, beam adjustment and so on. Cutting waveguide of Vlasov launcher, the analysis and design of mirrors are the keys to finally decide the entire mode converter performance.This degree thesis makes a research of the basic theory and basic design methods about the quasi-optical mode conversion technology. The launcher geometry structure formulas are derived by the application of geometrical optics theory. The ways of gradual change used for the circular waveguide to weak elliptical waveguide make the radiation performance of Vlasov launcher improved. To study the principles and design methods of the phase-corrected mirrors, using KSA algorithm to produce a self-adaptive design and analysis procedure about phase-corrected mirrors and according to the vector diffraction theory to develop a numerical analysis program. By these theories to design and simulate a 8mm band TEM00 to TE01 quasi-optical mode converter. By use of self-adaptive procedures to optimize, the relevant model parameters are derived and numerical model is set up to make the calculation. Using simulation software set up the corresponding simulation model, simulation results will be compared with the calculated results. Finally the model is processed to make the experimental research to verify the design method.