Effect of nonuniform-defect split ring resonators on the left-handed metamater ials

We have investigated the defect effect in three_dimensional (3_D) left_handed metamaterials, consisting of an array of repeated unit cells of copper wires and hexagon split ring resonators (SRRs) on strips of standard circuit board materi al. By measuring the X_band transmission through this metamaterial with differen t point_ and linear_defected SRRs, we find that the resonance frequency, its val ue and passband of transmission peaks, changes markedly. It is suggested that su ch tunable left_handed properties may arise from the symmetry breaking of SRRs i n the metamaterials.