Polarization-independent wide-angle ultrathin double-layered metamaterial absorber for broadband application

摘要

In this letter, a polarization-independent broadband metamaterial absorber (MMA) for wide incidence angle is proposed. The MMA is composed of double-layer symmetric split rings connected with two orthogonally arranged bars and the ground metallic plane separated by two equal-sized substrates. The whole structure is with an ultra-thin thickness of 2.4 mm, which is 0.031 corresponds to the lowest frequency of absorption peaks. Multiple metallic layers and multi-scalability are employed to provide broadband absorptivity based on the cooperated mechanisms of the Ohmic loss and the Fabry-Perot interference. A desirable absorption is achieved with double strong absorption peaks in 2-6 GHz and a broadband absorption in 10-24 GHz. The absorptivity can reach up to 100% with nearly all absorption peaks over 90%. The symmetry enables the MMA of satisfactory stability for polarization and incidence angles. Numerical and experimental results prove the capability of the proposed MMA for broadband absorbance.