Electrically tunable negative permeability metamaterials based on nematic liquid crystals

An electrically tunable negative permeability metamaterial consisting of a periodic array of split ring resonators infiltrated with nematic liquid crystals is demonstrated. It shows that the transmitted resonance dip of the metamaterial can be continuously and reversibly adjusted by an applied electric field, and the maximum shift is about 210 MHz with respect to the resonance frequency around 11.08 GHz. Numerical simulation shows that the permeability is negative near the resonance frequency, and the frequency range with negative permeability can be dynamically adjusted and widened by about 200 MHz by the electric field. It provides a convenient means to design adaptive metamaterials.