An example split-ring resonator consisting of an inner square with a split on one side embedded in an outer square with a split on the other side. Split-ring resonators are on the front and right surfaces of the square grid, and single vertical wires are on the back and left surfaces.[1][2]Electric field (top) and magnetic field (bottom) of an electric-SRR under resonant electrical excitation. The magnetic response arises[dubious – discuss] from the symmetry of the current loops.[3]
^Shelby, R. A.; Smith, D. R.; Nemat-Nasser, S. C.; Schultz, S. (2001). "Microwave transmission through a two-dimensional, isotropic, left-handed metamaterial". Applied Physics Letters. 78 (4): 489. Bibcode:2001ApPhL..78..489S. doi:10.1063/1.1343489.