Double-Layered Ceramic Disk-Constructed All-Dielectric Huygens Metasurface Perfect Absorber

Through the degenerate critical coupling of two resonance modes with opposite symmetries, all-dielectric metasurfaces, and photonic crystal slabs can completely absorb electromagnetic waves that are incident from a single side of their two-port resonator elements. However, only a few experimental samples in the terahertz and near-infrared bands have been reported to date. Here, by using two ceramic disk types with different losses to construct resonator elements with degenerate critical coupling characteristics, high microwave band absorption is realized in an all-dielectric Huygens metasurface. Experimental results show that when resonators composed of Al2O3 and BeO ceramic disks are inserted into a square array of circular air holes in a Teflon plate, the maximum absorbance of microwaves incident from a single side reaches 96.2%. By optimizing the BeO disk's height and position, the simulated absorbance can exceed 99.5%, i.e., near-perfect absorption. These all-dielectric Huygens metasurfaces provide effective structures for the perfect absorption of high-power microwaves.