Research Of Broadband Absorber Based On Electromagnetic Metamaterials

Absorbing materials are widely used in the fields of national economy and national defense such as electromagnetic radiation suppression,electromagnetic compatibility,and stealth of weapons and equipment.Traditional absorbing materials are limited by intrinsic electromagnetic parameters and electric size,existing problems such as narrow absorbing frequency band,large thickness for low-frequency applications,and low loss,and it is extremely difficult to improve performance.In recent years,metamaterial absorber(MA)can realize the regulation of electromagnetic waves in the target frequency band through the rational design of the geometric structure and arrangement of the resonant units,and has the advantages of adjustable electromagnetic parameters,flexible design,perfect absorption and so on,and it has received extensive attention.Therefore,based on the design idea of MA,this paper carries out theoretical research and performance design optimization of absorbing structure focusing on the characteristics of broadband absorbing,low frequency,light transmission,etc.A variety of MAs are proposed,and the absorbing mechanism and absorbing characteristics are analyzed through the combination of simulation and experiment.The main work of the paper is as follows:1.Research on broadband absorber based on resistive materials.The ohmic loss is introduced by replacing the metal material with a resistive film,and a broadband,high absorption,low profile MA is designed.The absorption rate of electromagnetic waves in the range of 3.0?24.3 GHz is more than 90%,and the relative bandwidth is 156%.Finally,the absorbing mechanism and absorbing characteristics are explored through surface current,energy loss,impedance matching,etc.Finally,absorbing samples are prepared by screen printing,and the broadband characteristics of the design are verified.2.Research on low frequency broadband absorber based on multilayer structure.For the low frequency absorbing demand,the unique design of the meander wire structure is used to reduce the resonance frequency,and the absorbing frequency band is expanded through the coupling between the multilayer resistive films.A wide-band MA with excellent low-frequency performance is designed,which realizes the electromagnetic absorption effect in the range of 1.9?18.0 GHz,and the working bandwidth covers the four bands of S,C,X,and Ku.The influence mechanism of the square resistance,the thickness of the dielectric layer and the polarization direction on the wave absorbing performance is explored,and the simulation results are verified by experiments.3.Research on transparent absorber based on Indium Tin Oxide(ITO)film.Two broadband MAs are designed using ITO film and transparent dielectric materials,and the research results can be used to meet the needs of electromagnetic wave absorption in a transparent environment.The two new designs can achieve high-efficiency absorption of incident electromagnetic waves in the frequency range of 3.45?9.68 GHz and 5.62?14.19 GHz,respectively.They have both broadband absorption and high light transmission characteristics,and have good polarization and oblique incidence stability.Finally,the correctness of the design is verified through sample processing tests.