Local field energy density enhancement in planar metamaterials

Abstract

We study local field energy density enhancement in planar metamaterials at normal incidence based on the finite element method. The microwave metamaterials composed of asymmetric resonators with/without quartz substrates 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 and the quality factor and local field energy density enhancement strongly depend on the asymmetry. The proposed metamaterial on glass substrate shows the high possible quality factor of about 1000 and energy density enhance factor of up to 150000. To reduce losses of metamaterials further, freestanding metallic structure is considered being treated as perfect electric conductor and real-loss metal respectively. Real metallic metamaterial provides a very sharp trapped-mode resonance having the quality factor of up to 1500.