Ultrathin and Omnidirectional Absorbing Metasurface Designed for Electromagnetic Shielding of Discrete Sources

With the rapid development of the electronic information industry, research on electromagnetic shielding devices is urgently needed. This work demonstrated a series of ultrathin absorbing units with the characteristics of dual-frequency and dual-angle omnidirectional reflectionless absorption. Each absorbing unit consists of two dual-frequency absorbing cells, which are capable of achieving nearly perfect absorption for the electric waves coming from the normal and oblique incident directions individually. After the spatial arrangement of the ultrathin and dual-frequency absorbing units, the absorbing performance of the implemented metasurface was studied at the circumstance where the discrete source was placed near and far from the metasurface. Full-wave simulation and practical experiment verified the validity of the proposed electromagnetic shielding device. To be more quantitative, the spatial voltage standing wave ratios were further calculated which satisfied the industrial requirements.