A controllable magnetic metamaterial: Split-ring resonator with rotated inner ring

The split-ring resonator (SRR) with a rotated inner ring is analyzed to assess the controllability of its magnetic resonant frequency. Numerical simulations were carried out to verify the proposed theory and the controllability. The results show that by rotating the inner ring, magnetic resonant frequency of SRR increases as the angle between the two splits decreases. Simulation results and theoretical predictions are consistent with each other, which indicates that the proposed theory is quite effective in analyzing the controllability. Implementation of the controllability of SRRs with rotated inner ring was realized by using control bars. The effects brought by the materials and radii of control bars were investigated, which shows that the use of control bars increases the magnetic frequency slightly and that materials and radii of control bars have little effect on the magnetic resonant frequency. The theory and implementation method of the controllability proposed in this paper is of great practical values in designing controllable magnetic metamaterials.