The magnetic toroidal dipole in steric metamaterial for permittivity sensor application

A new kind of metamaterial composed of metallic split-ring structure arranged in a two-dimensional array is designed, which shows the multipoles' resonances, especially the magnetic toroidal dipolar (MTD) resonance. The calculated scattering power proves that the resonance at 14.416 GHz is mainly excited by MTD response. Compared with the other two resonances excited by normal multipoles, MTD response has the strongest dependence on permittivity of substrate and background material, which has potential applications on permittivity sensor.