Design And Application Research Of Electromagnetic Metamaterial Absorber

With the rapid development of modern electric technology, metamaterials have become a research focus in the international academic community in recent years, and they have research and development potential and application space in defense technology fields, such as radar, antenna stealth, electronic countermeasures, etc. The discovery of metamaterials has opened up a new research direction to electromagnetic theory. The traditional radar absorbing material itself exists, heavy, thick, lack of flexibility and other shortcomings, which has been limited in application. As a branch of research in the field of metamaterials, by implementing impedance matching with free space, the incident electromagnetic wave can not be breflected on the surface of the structure and enters into metamaterial absorber's internal structure.Under the effect of dielectric loss and ohmic loss, it can transform electromagnetic wave into heat, in order to achieve perfect absorption. Therefore, using metamaterial technology to design new-style absorbing materials has become a new research direction of the electromagnetic field. In this context, the main work of this paper is to design metamaterial absorbers with the characteristic of perfect absorption based on studying the working mechanism of metamaterial absorber, and related research in terms of the application in antenna stealth also will be done. The article consists of the following three parts:The first part,a brief overview of the background significance,research status of electromagnetic metamaterial absorber are given. Then analysis the basic theory of electromagnetic metamaterial, focusing on the absorption mechanism of metamaterial absorber and electromagnetic parameters extraction method. Then introduce the basic performance parameters of absorbing material and antenna. Basic on this, this part proposes design requirements and main planning of this topic.The second part,design a single-frequency metamaterial absorber,and its application in antenna RCS reduction is studied. First, design a metamaterial absorber with all-metal back-plate structure. Using this structure can ensure zero transmission of electromagnetic wave and reduce the space scattering of electromagnetic wave. The absorber can exhibit an absorptivity of 99.9% at 10.2GHz. Compared with previous studies, the absorber possesses both the characteristics of wide incident angle, polarization insensitive and stable working frequency. Due to its less application research, the application of absorber in antenna RCS reduction is studied in this paper. Simulation results show that the antenna has an obvious RCS reduction in its working band without affecting its normal radiation. Therefore, we can effectively use it for antenna stealth and other fields.The third part, in order to increase absorber's working band, design a dual-band metamaterial absorber working in 6.3 GHz and 13.01 GHz using double-loop nested structure.The absorber can exhibit an absorptivity of 99% for vertical incident electromagnetic wave at two bands under the precondition of achieving impedance matching with free space. This absorber has the characteristics of wide incident angle, polarization insensitive, stable working frequency. It is my innovation that the previous studies can't have. In order to achieve the absorption of electromagnetic wave in both directions, this paper presents a dual-directional metamaterial absorber. By adjusting absorber's structure parameters, it can both achieve the absorption of different frequencies and the same frequency in two directions.This absorber also has wide incident angle characteristic, and it can achieve nearly-all-direction absorption for electromagnetic wave.