On/Off Switching of Absorption Spectra by Layer Shifting for Double-Layer Metamaterial-Based Absorber

This letter presents on/off switching of absorption spectra by layer shifting for double-layer resonator structures. For the proof of concept, a single-layer double-closed-ring resonator structure (DCRR) is designed, fabricated, and characterized in S-band. In experiments, the structure individually shows two absorption peaks at 2.77 and 3.77 GHz. Additionally, a double-layer structure is constructed by repeating identical single-layer DCRR structure along propagation direction and leaving a 1-mm-thick air gap in between them. In the double-layer case, the structure presents three absorption peaks at 2.74, 3.24 and 3.73 GHz. Finally, shifting the layers horizontally for 5-, 10-, 20-, and 30-mm shift amounts reveals that the first absorption peak disappears for 5- and 10-mm and the third absorption peak disappears for 5-mm shift cases.