Crankled S-ring resonator with small electrical size

Metamaterials with small electrical size are more feasible to be described by the macroscopic parameters and treated as an effective homogenous media. By using geometric optimization, we experimentally realize a metamaterial composed of crankled S-ring resonator, whose electrical size is 2.5 times smaller than the conventional S-ring resonator. The overall effective capacitance of the unit structure is greatly increased when viewed from an equivalent circuit model point of view, so the resonant frequency is decreased, and the metamaterial works at a much longer wavelength regime. In addition, we summarize two kinds of other methods that could be used to reduce the electrical size of the structures. Experimental and simulation results are presented, showing the effectiveness of these methods in the metamaterial homogenization.