Research And Manufacture Of Special-shaped Luneburg Lens Antenna Based On Polymer-ceramic Composite Material

Luneburg lens antenna has the advantages of high gain,low sidelobe,wide scanning range,etc.,and has broad application prospects in the fields of electromagnetic countermeasures,industrial Internet,satellite communication,Internet of Vehicles,5G and 6G application markets.However,there are few types of low-dielectric-constant materials that can be used to make Luneburg lenses on the market,which are expensive,difficult to process,and difficult to control the dielectric constant of the material.Aiming at the problems of immature material development and heavy weight of the current Luneburg lens in engineering applications,this paper proposes a new type of high-dielectric constant special-shaped Luneburg lens antenna with small mass and excellent performance.From theoretical research,material selection and performance.The production process of special-shaped Luneburg lenses is fully introduced in terms of characterization,lens production,testing,etc.contents are as follows:1.First,a low-dielectric constant Luneburg lens working in the X-band is designed.The lens diameter is 190mm,and the three-layer structure is designed.Then the low-dielectric constant Luneburg lens is compressed by the quasi-conformal transformation optics method.a three-layer elliptical Luneburg lens was obtained.Compared with the low dielectric constant Luneburg lens,the elliptical Luneburg lens after compression transformation has the problem of performance degradation due to the change of the structure and the increase of the dielectric constant,so special spherical and elliptical Luneburg lenses are used.Combined,a novel high-dielectric constant Luneburg lens antenna with a diameter of 190 mm is obtained,and the obtained special-shaped Luneburg lens has similar performance to the low-dielectric constant Luneburg lens antenna.The feed source used in the lens is a coaxial waveguide converter,which can convert the TEM mode of the coaxial line into the TE₁₀ mode of the rectangular waveguide.After CST simulation,its S parameters meet the requirements for use,and the symmetry of the pattern is good.2.The SrTiO₃/PDMS polymer-ceramic composite material mixed with polydimethylsiloxane（PDMS）and strontium titanate（SrTiO₃）ceramic powder was selected to prepare the proposed special-shaped Luneburg lens.The process is introduced in detail,and then the composition,structure,microscopic morphology and dielectric constant of SrTiO₃/PDMS polymer-ceramic composites are characterized.The composite material has a relatively stable dielectric constant in the entire X-band,the dielectric constant is easy to control,and can be prepared at low temperature,and the measured value of dielectric loss is lower than 0.008.Finally,using the injection molding process,the prepared polymer-ceramic composite material was injected into the 3D printed mold to illustrate the production process of the special-shaped Luneburg lens.The 3D printing technology can well ensure the accuracy of the mold and can provide rapid Low-cost molds needed to make Luneburg lenses.3.In order to verify the design theory and physical objects,the fabricated SrTiO₃/PDMS polymer-ceramic composite special-shaped Luneburg lens was tested.After actual testing,the simulated gain values of the special-shaped lens antenna are21.1 d Bi,22.2 d Bi,22.8 d Bi at 8.5 GHz,10 GHz,and 12 GHz,respectively,and the measured values are 20.8 d Bi,22.4 d Bi,and 22.6 d Bi.The average is lower than-19d B,and the test results are basically consistent with the simulation results.The gain of22.5 d Bi and a side lobe level less than-22 d B at the center frequency of 10 GHz,the3 d B beamwidth in the azimuth plane is 9.8°,and the gain drop of the Luneburg lens antenna is only 0.7 when scanning to±54°in the azimuth plane d Bi,and the lens has the advantages of light weight（3.5 kg）,simple material preparation process,short production cycle and seamless molding at low temperature.After testing,the performance of the lens antenna is in good agreement with the simulation results.