Research On Structures Design And Performance Of Metamaterial Absorbers

In recent years, researches on novel artificial electromagnetic materials have attracted more and more researchers' attention. It provides many possibilities for many new physical phenomena and the design of new devices. Among them, the production of absorption materials based on the novel artificial electromagnetic materials becomes more and more important in applications of many other fields besides military field. The.main purpose of the absorber development is to increase the absorption of the material, while making the absorber structure to meet the "light, thin,wide, high" characteristics. Therefore, this paper presents a new method and a new parameter, after modeling and simulation analysis, results show that the novel method increases the bandwidth of the absorber to a certain extent. This paper provides a new idea for the optimization of absorbing materials, and it is of great significance to the application of novel artificial electromagnetic materials.My contributions in the main contents of the research include the following three aspects:1. Analyzing the electromagnetic parameters of the novel artificial electromagnetic material theoretically. According to Floquet theorem, we can get the relationship between the equivalent permittivity and the equivalent permeability of the metamaterial and the average permittivity and the average permeability of the cell. The S parameters of the cell can be obtained by simulating NIM structure with HFSS simulation software.Then the average permittivity and the average permeability of the cell are obtained by NRW algorithm. It is found that the metamaterial is effective only in a specific frequency band determined by dimension of the structure.2. Analyzing and comparing the existing methods for optimizing the performance of the metamaterial absorbers, such as 1) the effects of different FSS designs, 2) the analysis of multi-layer absorbers and the optimization of absorption performance and 3) the analysis of the optimization algorithms on simulation platform. Based on the existing optimization methods of metamaterial absorber, we propose a novel structure of curved-surface metamaterial absorber and a new optimization parameter named the degree of deformation. This absorber can combine multiple narrowband absorption peaks into one broadband absorption peak. In this paper, after simulating the curved-surface metamaterial absorber, we compare it with the planar absorber before doformation. The results show that the novel method has its advantage in absorption bandwidth.3. Realizing a broadband metamaterial absorber with absorption bandwidth across both the C and X bands. Using the proposed curved-surface absorber model, selecting the rings as the frequency selective surface pattern and using a double-layer structure, the results after the simulation show that the bandwidths of multiple absorption peaks of the planar structure are extended. Besides, it ensures high absorption rate within the broad bandwidth. In addition, we simulate and analyze the performance of the deformation parameter; the result presents the relationship between the deformation parameter and the optimized absorption frequency.