Design and analysis of an ultra-thin dual-band wide-angle polarization-insensitive metamaterial absorber for C-band application

Abstract

This paper presents an ultra-thin metamaterial absorber (MMA) which can execute two absorption peaks in the C-band. It is polarization-insensitive to the incident wave and has the satisfactory absorption under the wide incident angle. The proposed dual-band MMA is a three-layer structure, the top layer is consisted of a central cross resonator and an external circle ring resonator, the bottom layers is made by copper, and the middle layer is filled in the dielectric FR-4. The calculation results show two diverse absorption bands at the resonance frequency of 4.44 GHz and 7.85 GHz, whose absorbance can reach 99.93 % and 99.99 %, respectively. The structure of the proposed MMA is simple and its thickness is only 1.47 % of the wave length at minimal resonance frequency. In addition, the calculation demonstrates the proposed MMA is insensitive to the various angles of polarization, and it also shows the proposed MMA can attain high absorptivity under the wide angles of incidence in TE and TM modes. Furthermore, the absorption mechanism of the proposed MMA is studied, and the specific effect of the geometric parameters of top resonator and the dielectric thickness on absorptivity are also analyzed. At last, the absorption performance of the proposed dual-band MMA is verified by experiments, which is basically consistent with the simulation effect. The proposed MMA can be applied in C-band radar antenna, satellite communication or other relative fields.