Research On The Design Method Of Multilayer Thin Broadband(1-18GHz) Absorbing Materials

Absorbing materials refer to a class of functional materials that can effectively absorb and lose the energy of incident electromagnetic waves,and have important application values in the fields of stealth technology,electromagnetic compatibility,and electromagnetic radiation protection.However,traditional absorbing materials,such as magnetic absorbing coatings,honeycombs,and absorbing foams,have disadvantages such as high surface density and large structural thickness;while artificial electromagnetic periodic structures,such as frequency selective surfaces,dipole resonators,and Salisbury screens and so on,there are shortcomings such as narrow absorption frequency band and large structure thickness;it is difficult to meet the application requirements of the development of electronic information technology for low frequency thin broadband.Therefore,combining traditional magnetic absorbing materials with artificial electromagnetic periodic structures is expected to solve the problem of low-frequency thin-bandwidth absorption.In view of the above problems,this thesis studies two types of absorbing structure materials:(1)Designing a double-peak absorbing structure in the 1-8GHz frequency band based on magnetic composite materials,systematically simulating and optimizing the absorbing unit and structural parameters,through screen printing Prepare test samples and test and verify the simulation results;(2)6-18 GHz stepped broadband composite magnetic absorbing structure is designed based on electromagnetic diffraction and standing wave resonance theory,and the structure parameters are simulated and optimized.The laws and main conclusions are as follows:1.1-8GHz double-peak absorbing structure regulation law: the periodic arrangement spacing increases,the absorption peak blue shifts,the absorption peak in the L band decreases,and the peak value in the S and C bands increases;the internal structural parameters of the periodic unit regulate the 2-8GHz frequency band The absorption peak position within the internal;the absorbing structure with a thickness of1-2mm maintains the bimodal characteristic,the greater the thickness of the magnetic substrate,the greater the absorption peak intensity;the analysis of the dispersion distribution of the periodic surface current,realizes the resonance of different frequency bands to expand the absorption bandwidth.2.The simulation and experimental results show that compared with the homogeneous magnetic material of the same thickness,the 2mm double-peak absorbing structure has a 48% improvement in L-band absorbing performance(-4d B bandwidth),but the absorbing performance is to a certain extent in 2-8GHz.Reduce,effectively improve the absorbing performance of magnetic materials in the L-band;the test results are basically consistent with the simulation.3.The regulation rule of 6-18 GHz broadband magnetic absorption structure: the period size of the two layers becomes smaller,the absorption peak blue shifts and the absorption bandwidth becomes wider;the greater the thickness of the upper layer,the smaller the thickness of the lower layer,the absorption peak moves to high frequency and the bandwidth becomes Wide;compared with the homogeneous magnetic material with the same thickness of 2mm,the 6-18 GHz wave absorption performance is improved by an average of 3 times.This paper systematically analyzes the regulation rules of two types of absorbing structures.The combination of magnetic materials and artificial electromagnetic cycles is beneficial to the improvement of low-frequency performance.The stepped broadband magnetic absorbing structure greatly improves the high-frequency absorbing performance,which is useful for further design of thinner Broadband high-efficiency absorbing materials provide new ideas.