Research And Design W-Band Beam Waveguide Antenna System

Beam waveguide has been widely used for guiding short millimeter wave because of its characteistics such as low loss, wide band and easy maintenance. Recently, the demand of short millimeter antennas with high gain and low side lobe is increasing especially in deep space detection, meteorologic survey and satellite remote sense etc.So research and design beam waveguide antenna is important.The thesis is summarized as follows:Firstly, according to the gaussian beam waist and radiation pattern, a 3mm band corrugated conical horn is rapidly designed, then mode matching method is used to analyze the horn, simulation results indicate the design completely meet our need.Considering the cost, we have designed and fabricated a dual mode horn with good performance which can transmit high fundamental gaussion beam, the simulated and tested results are in fairly good agreement. This dual mode horn will be used as guassian feed in the W-band beam waveguide antenna system.Secondly, we made use of the gaussian beam method to design single beam waveguide such as flat, parabolic, ellipsoidal mirror. The influence of radiation pattern by the size of flat mirror is given, then the wideband property of beam waveguide is proved in theory. On the basis of these analysis,a beam waveguide meeting the actual need is designed. To real-time, wideband and rapidly measure the scattering parameter, a new method called terminal mathing mirror method is proposed. Considering the current application,the demand of surface error is discussed.At last, wire grid polarization separator and grid-plate circular polarizer have been designed in order to actualize frequency reuse technique,the axial radio in the 23dB beam width of the designed dual grid-plate circular polarizer is less than 1dB. The influence on electric performance by four independent parameters of offset cassegrain antenna have been analyzed, then excellent parameters was gained.Considering the high-power problem, we introduced an offset near-field cassegrain antenna fed by single parabolic beam waveguide, the simulation results prove that the new beam waveguide antenna has very low cross polarization and side lobe level.