Water‐Resonator‐Based Metasurface: An Ultrabroadband and Near‐Unity Absorption

Metasurface absorbing material, which obtains near‐unity electromagnetic absorption through subwavelength artificial structure, plays an important role in the area of stealth and shielding technology, biological imaging, etc. However, they usually suffer from narrow bandwidth and only work on planar surfaces. Here, for the first time, this study demonstrates a soft water‐resonator‐based metasurface, which functions as an active absorbing material across an ultrabroadband range of Ku, K, and Ka bands. Distinct from conventional metallic metasurface, the water‐resonator‐based metasurface absorbs the microwave by dielectric magnetic resonance and periodic grating effect, which has a perfect absorptivity of ≈99% and an absorption bandwidth (absorptivity higher than 90%) that covers 78.9% of the central frequency. Furthermore, near‐unity absorption is maintained when the soft metasurface material is bent into different curvatures, promising high potential applications for antennas in reducing side lobe radiation, eliminating wall reflection in anechoic chambers, antiradar detection, and stealth.