Design And Research Of Overmode Circular Waveguide Mode Converter

With the development of high-power microwave-related technology and the more systematic study of microwave technology by scientists,high-power microwave technology has been applied in many fields such as the national defense and social sciences.The operation of high-power microwave systems are inseparable from the conduction structure of high-power microwaves,in which the mode converter plays a vital role.The size and efficiency of the mode converter determine the utility of the mode converter.The main work of this paper is to design some high efficiency and compact mode converter.Commercial electromagnetic simulation software can accurately calculate the mode coupling problem in the mode converter,but it requires high computing performance and long computing time.When designing the mode converter,it is often necessary to repeatedly optimize the structure of the mode converter to design a high-efficiency mode converter.Therefore,it is necessary to write a numerical calculation program.The author used different optimization design methods to write the MATLAB design program,design a variety of practical mode converters and compared with simulation results.The work and research results of this paper are as follows:Combined with the principle of mode conversion of axis-bending circular waveguide mode converter and axis-line mode converter,the numerical solution method in mode converter design is studied.The Runge-Kutta method is used to solve the mode conversion efficiency of the mode converter and simulated annealing algorithm is used to optimize the structural parameters of the mode converter.The author has carried on the thorough research to the iterative design method,and has compiled the MATLAB numerical calculation program using the iterative method to design the axis curved smooth circular waveguide mode converter.An iterative method MATLAB numerical calculation program was used to design a TE01 right-angle bend transition with a working frequency of 32 GHz and a waveguide radius of 16 mm,using CST for simulation verification.In addition,the author also studied the simulated annealing algorithm,and compiled the MATLAB numerical optimization design program of the axially curved smooth circular waveguide mode converter optimized using the simulated annealing algorithm.The TE01-TE11 mode converter with an operating frequency of 32 GHz and a waveguide radius of 14 mm was designed using a mode converter design program based on simulated annealing,a mode converter design program based on iterative method,and a mode converter design program based on the combination of two methods.TE01-TE11 mode converter designed by three design methods were verified using CST simulation software.Combined with the coupled-wave equation of the axial linear smooth waveguide,the coupling coefficient between the modes,and the numerical solution method of the differential equation,the MATLAB numerical calculation program for axis linear smooth circular waveguide mode converter is compiled.Based on this numerical calculation procedure,a TE01 mode taper with a working frequency of 32 GHz and a waveguide radius of 16 mm-14 mm was designed using some waveguide structure with different radius variation function,and it was verified using CST.In addition,the author also used the simulated annealing algorithm as the optimization algorithm,and combined the MATLAB numerical calculation program of the linear smooth circular waveguide mode converter to design the TE02-TE01 mode converter with double disturbance structure or three disturbance structure,using CST for simulation verification.The TE02-TE01 mode converter's operating frequency is 28GHz and the radius of port is 20mm.In addition,iterative method is also used to design the above two mode converters.