Millimeter-wave Variable Modeling Techniques Theoretical Research

A certain HPM system generally include input coupler resonators system in HPM sources, HPM transmitting system, the output coupling system, waveguide mode converters, the transmitting and receiving antennas. The designing behavior of each subsystem usually plays an utmost important part in the whole HPM system. The HPM mode transformer plays an extremely important part in the HPM transmitting and receiving process. It can make the energy of HPM source to transmit and radiate in a requisite mothods. Therefore, it has very important value to study and apply. The mode converters of several kinds of HPM sources especially the gyrotron are studide in this paper with theoretical analysis and numerical simulation in depth. The mode converter with design and manufacture apply in the experiment of our research institute successfully. The main works of the paper are listed as following:Waveguide mode converter:First, the issue of mode coupling in the radius changed and axis bent overmode circular waveguide is studied on the basis of coupled wave theory. The coupled-wave equation and its coupling coefficient expression in the radius changed and axis bent overmode circular waveguide are summed up.Second, present a method called Runge-Kutta to solve the coupled wave equation mumerically. Obtain the optimization geometrical structure parameter of the mode converter under different frequency and bandwidth condition. Adopt the different geometrical structure and phase rematch technology to design the efficient, wideband and tight circular waveguide mode converter. The mutual relationship about the radius of the waveguide, curvature of bent circular waveguide, frequency and the bandwidth are also obtained.Quasi-optical mode converter:First, the issue of mode coupling in the asymmetric circular waveguide is studied on the basis of coupled wave theory. The coupled-wave equation and its coupling coefficient expression in quasi-optical Denisov mode converter are summed up.Second, based on the coupled wave theory and quasi-optical theory, obtain the optimization geometrical structure parameter of the quasi-optical mode converter.