An Ultrathin Double‐Side Flexible Metasurface for Ultrawideband Electromagnetic Absorption

In this article, we propose a novel ultrathin double‐side flexible metasurface (DSFM) with multi‐resonators to accomplish the ultrawideband electromagnetic (EM) microwave absorption. The proposed DSFM is mainly consisted of only ~0.2 mm double‐side resonators with four centrosymmetric split square‐loop arrays (SLAs) and ring‐round arrays printed on upper‐side layer, as well as hollow‐ring structure arrays printed on lower‐side layer. Among lumped resistors embedded on the edge of split SLAs yield the resistance loss, air medium layer between DSFM and a metal ground below generates the dielectric loss and EM loss, respectively. Taking advantage of equivalent circuit model, input impedance, and surface current distribution, EM absorption mechanism can be revealed based on the synergistic effect of Ohmic loss and inner field coupling interference of double‐side surface resonators. Via the optimization, simulation, and experimental validation of designed DSFM, the fabricated absorber demonstrates above 90% absorption bandwidth at 6.95–17.01 GHz (128% of fractional), superior polarization insensitivity, flexibility, and oblique incidence absorption stability. Owing to this excellent performance, DSFM absorber will contribute to the integration development of EM stealthing and radar detection.