Quad-band polarization-independent flexible ultra-thin coding defect support absorber for frequency ranges from C to Ku band

Abstract

Simple and ultra-thin structure with high efficiency in absorbing electromagnetic waves in adjacent frequency bands are of great interest nowadays. Metamaterial or metasurface is one of the leading candidates for such studies. In this paper, by employ the open square frame structure combined with the central polygonal disk of the base cell, we built an absorber material with high symmetry and possessing four separate absorption peaks at adjacent frequencies in the C, X, Ku-band (4 GHz to 16 GHz). Notably, the four peaks have high absorption and are quite equally distant. The polarization-dependent analysis also shows that the structure possesses wave polarization independence and still ensures high absorption at incident angles as wide as 60 degrees. In addition, due to the ultra-thin nature of the structure, it also shows a flexible wave absorption response at different bending angles with special requirements. Moreover, a coding defect surface is applied to study the real-life application possibility of the full-size structures and shows that the absorption is stable with a concrete number of defects. This structure has high applicability in electromagnetic stealth technology, communication technology as well as related directional electromagnetic wave control requirements.