Design Of Beam Forming Surface With Sub-wavelength Structure

Beam-shaped surface antennas have a wide range of applications in mobile communications,radar,remote sensing technology,and radio astronomy.They can adjust spherical electromagnetic waves emitted from the feed to a directional beam,thereby obtaining significant antenna gain.With the rapid development of mobile communication technology,higher requirements are placed on beam forming surface antennas.This article will take the beam-forming surface as the research object,based on the compact field theory and geometric optics principles,by analyzing the electromagnetic field distribution,quiet area performance and space power synthesis,etc.,the compact field of the beam forming surface in the millimeter wave band 26.5 ? 40 GHz and 5G NR production line test spherical beam forming surface compact field design.The main research content and work of this article can be summarized as:1.The single parabolic beam forming surface of the millimeter wave compacted field is studied.Firstly,based on the geometric optical characteristics of the parabola,the initial parabola is designed and its static area performance is analyzed.It is found that the static area performance is greatly affected by the parabolic edge diffraction(amplitude fluctuation exceeds 5d B,phase fluctuation exceeds 10 °);then the traditional edge is used Diff raction processing method-sawtooth distribution method(through the sawtooth gradient to reduce the electromagnetic wave energy radiated to the parabolic edge)and curvature curling method(through curling to radiate the edge electromagnetic wave energy to the non-test area)to optimize the performance of the quiet zone,It is found that these two methods have limited improvement in the quiet zone and are limited in practical applications.For example,excessively long saw teeth will greatly increase the vo lume of the microwave dark room,and excessive curling curvature will greatly increase the difficulty of processing;then the traditional edge method is proposed The mixed edge method of absorbing materials(resistance,dielectric and magnetic medium)with different loss media is found.The mixed edge method has obvious improvement in the quiet zone.The mixed method of magnetic medium can make the amplitude fluctuation of the quiet zone less than 2d B,and the phase fluctuation is less than 10 °;Finally,a new edge processing method—subwavelength structure edge method is proposed,Equivalent circuit theory and periodically arranged sub-wavelength structure unit,so that electromagnetic wave energy radiated into the edge of the radiation direction is changed and the attenuation(non-radiated to the test area),such that the final dead zone is less than 2d B amplitude fluctuations,phase fluctuations of less than 10 °.2.To 5G NR(0.6 ? 6GHz)production line testing ellipsoid compact range studied.First,the working principle of the ellipsoidal mirror is studied,which has a convergence effect on the electromagnetic waves radiated by the feed antenna placed at the ellipsoid;then,the initial ellipsoidal model is designed using the principle of ellipsoidal near-field focusing,and it is found that there is a focus test at the focus Blind zone(the test data fluctuates greatly,which is easy to cause misjudgment of the test result);then the combined design of the inner surface of the ellipsoid and the outer surface is used to make the electromagnetic wave produce a 90 ° phase difference when focusing,to achieve the defocusing effect;finally,after optimization The ellipsoidal beam forming surface is sampled in kind and placed in a darkroom environment for testi ng.The actual measurement shows that the change trend of the batch cell phone test results of the ellipsoid dark room is consistent with the change trend of the performance test results of the large microwave dark room.The test time of the ellipsoid dark room is 1/5 ? 1/8 of the test time of the large dark room.Therefore,the designed ellipse Spherical darkroom can help production line engineers quickly screen out bad machines and improve production line efficiency.