**Figure 2.**

*The array of split-ring resonators plus wire assemblies.*

• In 1999, John Pendry was the first to identify a practical way to make a lefthanded metamaterial. Pendry's theoretical idea was that metallic wires aligned along the direction of a wave could provide negative permittivity (ε < 0), and a split ring with its axis placed along the direction of wave propagation could do so could provide negative permeability. In 2000, Smith et al. reported the experimental demonstration of functioning electromagnetic metamaterials by stacking, periodically, split-ring resonators and thin wire structures as shown in **Figure 2**.
