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

This paper presents an ultra-thin triple-band metamaterial absorber (TMMA) for the X-band which is insensitive to polarization and has high absorbance to wide incident angles. The TMMA is a three-layer structure based on the combined resonator which is made of a slotted rhomboid ring and a double cross pattern structure. The calculation indicates that the proposed absorber has three absorption peaks at 7.48 GHz, 9.70 GHz and 11.27 GHz with absorption rates 99.88%, 99.99% and 99.97% respectively. The TMMA’s structure is simple and ultra-thin, its thickness is only 0.0258 λ (the wavelength at the minimum absorption frequency can be expressed as λ). Also, it has the characteristics of being insensitive to the polarization of incident waves and it attains high absorbance to wide incident angle. The distribution of electric field, magnetic field and surface current in the TMMA is discussed, and the absorption mechanism of the proposed TMMA is expounded. Experiment results indicate that theoretical calculations and simulations are effective. The MMA can be used in broadcasting, communications, meteorology and earth observation satellites.