An ultra-wideband, polarization insensitive, and wide incident angle absorber based on an irregular metamaterial structure with layers of water

We present the design of a new type of irregular metamaterial structure that can achieve ultra-wideband absorption. The structure is created using 3D-printing to create a shell and contains multiple layers of water. The structure can achieve absorption levels greater than 0.9 in the 6.8-21.0 GHz range, with a relative bandwidth of 101.93%. The absorber also works in a wide range of incidence angles with different modes and is polarization insensitive. Measurement results obtained from a microwave experiment coincide well with the simulation results. The proposed metamaterial could be broadly applied in various civilian and military products in the future. Published by AIP Publishing.