Design and analysis of a polarization-independent and incident angle insensitive triple-band metamaterial absorber

Abstract

A triple-band metamaterial absorber (MMA) which is composed of a traditional metal-dielectric-metal structure is proposed in this paper, three absorption peaks are located at S-band, C-band and X-band, respectively. The design parameters are obtained by the methods of controlling variables and iterative optimization, and three perfect absorption peaks exceeding 99% are acquired at 3.72 GHz, 5.86 GHz, and 10.54 GHz after numerical calculation and analysis. Subsequently, the impedance matching conditions for absorption are proved through the analysis of equivalent electromagnetic parameters. For the proposed MMA, polarization independent characteristic, which is produced from the symmetry properties of the structure is verified, and it also has a stability of incident angle in both TE and TM modes from the result of the analysis of oblique incident response. In addition, its absorption mechanisms and methods are discussed and analyzed through electromagnetic field and surface current distributions. At the same time, the triple-band absorption performances of the proposed MMA derived from the material losses, 2D microstructure of the top layer and dimension parameters have also been calculated and investigated through the discussing of certain parameters individually. Finally, the absorption performance of the MMA is tested through experiments, and experimental results are basically same as the simulation results. Compared with other studies, the MMA proposed in this paper has higher absorption peaks at the resonance points, and the thickness is only 0.013 times of the longest working wavelength, which has a thinner thickness. The proposed MMA can be utilized in the areas of the decrease of Radar-Cross-Section, electromagnetic shielding, sensing and other applications.