Experimental observation of the electric coupling effect in split ring resonators and the prevention

We studied experimentally the transmission properties of arrays of split-ring resonators (SRRs) for different electromagnetic polarizations in the microwave-frequency regime. It is known that, besides the electric response through the cut-wire like, another electric coupling to the magnetic resonance of the SRR appears when the incident electric field is parallel to the gap-bearing sides of the SRR. The resonance frequency of this effect is very close to the magnetic resonance. This might degrade or even destroy the left-handed properties of the material when the SRRs are combined with the wires. To avoid this effect we have changed the structure of SRRs from an asymmetric one with a single gap to a symmetric one with two gaps. The results are also compared with the previous studies.