Sharp Fano resonance in a water-based toroidal dipole metamaterial

Abstract

The toroidal dipole is implemented by abundant and bio-friendly water with a high dielectric constant in the microwave range. A Fano resonance, with high Q-factor up to 152, resulting from enhanced fancy toroidal dipole could be stimulated at 1.65 GHz. Analysis of the induced current and near- and far-field shows that energy can be concentrated in distilled water, and the intriguing toroidal dipole plays a decisive role in resonance. Under different size parameters and conductivity of water-based metamaterial, the toroidal excitation and its influence on transmission characteristics are discussed. The toroidal dipole excited in distilled water might be of great significance for designing ultra-sensitive sensors, absorbers, and slow-light devices.