Study Of High-power Millimeter-wave Antenna Duplexer

High-power microwave systems generally refers to peak power of more than 100MW, the frequency between 300MHz ~ 300GHz, the wavelength span in the millimeter to centimeter-wave electromagnetic waves between the generation, transmission, and launch systems.The application in military and industry promotes the high-power microwave research has made rapid development. In recent years, microwave system shown to high-frequency, high-power direction of the trend.As the millimeter-wave system power is usually high, the traditional method to achieve duplex in the microwave transmission lines is no longer applicable, must be applied to high-power millimeter wave antenna duplexer, the internal antenna to achieve duplex.Flame tube, circulator, switch duplexer can be realized, but not used in high power millimeter wave systems, more appropriate method is to apply metal grating duplexer, the advantage of the power capacity limits can be overcome. This paper is a kind of metal grating high-power millimeter-wave antenna duplexer, the core device is a polarizer and a polarization splitter. Firstly, in order to free space Floquet-mode theory and the planar waveguide transmission theory, deduced the structure of single-stage reflection S parameter matrix, prepared by the corresponding numerical calculation program. Using this program, high-frequency characteristics of metal grating structure analysis and verification, and then get the Ka-band rectangular grating polarizer and the polarization separator preliminary design.On this basis, using the cascade pattern matching method and the ladder approximation combined analysis of arbitrary cross section of the preparation of a periodic grating reflective common procedures, the period of grating groove width, depth and angle of incidence on the polarizer the TE wave and TM wave phase and polarization separator -1 order diffraction beam reflection coefficient were obtained. The conclusion that the parabolic metal grating polarizer axis ratio <1.1, the bandwidth of> 10%, parabolic splitter TE wave -1 order diffraction beam with parameter amplitude greater than 85%.According to the parameters obtained by electromagnetic simulation software with the simulation results better match the numerical results prove the correctness of the numerical calculation. Duplexer is optimized for power has a high capacity and bandwidth upgrade.