Tunable Transparency Effect in a Symmetry Metamaterial Based on Subradiant Magnetic Resonance

We proposed, designed and demonstrated a tunable transparency effect at microwave frequencies in a symmetry metamaterial consisting of an "I" shape of cut wire surrounded by a two-gap ring. The excited mechanism of the tunable transparency effect is investigated by theory and simulation. It was found that this active modulation originated from the excitation of the subradiant magnetic resonance based on phase couplings. In particular, it is numerically demonstrated that the resonance quality factor (Q factor), the local field energy enhancement, and the effective group index of the metamaterial can be actively manipulated based on phase couplings. It may inspire interest in the developments of electrically and magnetically tunable transparency metamaterials, leading to a wide range of active slow light devices.