An ultrathin and dual-band bidirectional metasurface absorber based on ring-disk resonators

In this paper, an ultrathin and dual-band bidirectional metasurface absorber (MSA) based on ring-disk (RD) resonators structure. The simulation results indicate that the proposed MSA can achieve a high absorbance of 95.1% and 93.6% at 6.64 GHz and 13.36 GHz, respectively, for both forward (+ z ) and backward (− z ) incidences, which is effectively validated by the experiment. The retrieved equivalent electromagnetic (EM) parameters and simulated surface current distributions demonstrate that the dual-band high absorption is mainly attributed to the fundamental dipolar resonance excited by the ring-shape (RP) and disk-shape (DS) resonators, respectively. Moreover, the designed bidirectional MSA can achieve wide-angle absorption for both transverse electric (TE) and transverse magnetic (TM) modes. Furthermore, the absorption performance of the bidirectional MSA can be tuned by varying the geometrical parameters of the unit-cell structure. The proposed dual-band bidirectional MSA has promising application prospects in detection, sensing, and imaging.