Ultra-narrow resonances and near-field energy density enhancement in planar cross-linked metamaterials

We theoretically predict ultra-narrow resonances in planar cross-linked positive and negative metamaterials at normal incidence. The microwave metamaterials composed of cross-linked asymmetrically split rings or apertures with quartz substrate are utilized to investigate the resonant response to incident electromagnetic waves. The trapped-mode resonant feature results from the excitation of an antisymmetric current mode due to the broken symmetry between two resonators. The quality factor and near-field energy density enhancement strongly depend on the asymmetry. For optimized structure parameters the metamaterial on quartz substrate shows a quality factor of about 1000 and an energy density enhanced factor of up to 150,000. (C) 2011 Elsevier B.V. All rights reserved.