W Band High-power Antenna Duplexer Research

Weather radar by measuring the scattering of rain, clouds, ice, snow and water in the atmosphere into the matter on the radar transmit pulse echo power to speculate that the water content, cloud contours and spatial distribution.Atmospheric detection is an important part of the Atmospheric Sciences, is the basis of meteorological services and meteorological services, to improve the accuracy of weather forecasting, and improve the level of atmospheric sounding technology is a priority.Millimeter-wave refers to electromagnetic waves between1-10mm, in view of the millimeter-wave detection capability, high measurement precision and high temporal and spatial resolution, millimeter-wave radar has become the main tool to probe the vertical structure of cloud.The millimeter-wave radar is the most commonly used two atmospheric window band is35GHz (8mm) and94GHz (3mm),8millimeter-wave radar is mainly used for ground detection,3millimeter-wave radar is mainly used for airborne and space borne.With the shortening of the wavelength of electromagnetic waves, traditional diplexer difficult to adapt to the high power requirements of the microwave.Transmission metal grating duplexer can overcome the limitations of the power capacity in the W-band work, however, the grating bars to be machined to very fine airborne vibration prone to make the system performance is extremely deteriorated.In this paper, a reflective metal grating duplexer, its core is the reflection metal grating circular polarization and the reflection metal grating polarization beam splitter.Both able to adapt to the requirements of high power, airborne when the performance is not easy to be affected.Firstly, the use of space Floquet-mode theory and mode matching made a detailed analysis of the scattering characteristics of grating, and derive a matching equation in the grating face and the waveguide internal mutation interface, and gives the equation of the scattering matrix of the cascade.In view of the particularity of the reflection grating, gives a more effective cascade, in theory, is four times the speed of traditional cascade calculation.Then, write the corresponding computer program, application programs written in design W-band rectangular grating circular polarization, and the application of the ladder approximation method is optimized to get a double U-shaped grating, have a greater power and bandwidth.Finally, according to the parameters on the CST model, simulation results show that the dual U-shaped grating right-handed polarized wave and L polarized wave difference between33.078dB, the center frequency of94GHz on the axis ratio of0.47dB, wella right-handed polarization change.Again, the use of written procedures designed rectangular metal grating polarization beam splitter, to optimize the design of a double U-shaped and SIN-shaped grating in order to improve the diffraction efficiency of the polarization beam splitter, the latter high diffraction efficiency, able to ensure that TM wave in accordance withO beam diffracted at the same time, TE, almost all transformed into-1order diffraction beam to achieve a polarization beam splitter.