An ultra-thin flexible conformal four-band metamaterial absorber applied in S-/C-/X-band

In recent years, many kinds of multiband metamaterial absorbers (MMAs) have sprung up. However, most of their dielectric layers were filled with rigid dielectric materials, which has many limitations in practical application. In this paper, an ultra-thin flexible conformal four-band metamaterial absorber (FMMA) is presented based on the dielectric material of polyimide (PI), and its thickness is only 0.0047 of the wavelength at the lowest absorption frequency. The top resonator is adopted a hollow structure, which is different from the common strip and ring structure, providing a novel idea for multiband absorber design. The proposed FMMA achieved four absorption peaks with an absorptivity higher than 90% from S-band to X-band. Meanwhile, in both TE and TM modes, it is insensitive to polarized waves and maintains good absorption under a wide incident angle. The experiment is carried out to demonstrate that the FMMA has satisfactory absorption performance. Due to its flexible conformal characteristic and good absorption performance, the FMMA can be applied in electromagnetic shielding of a curved surface, meteorological satellite, and radar detection.