Effective Dielectric Response of Metamaterials
We use a homogenization procedure for Maxwell's equations in order to obtain in the local limit the frequency ($ω$) dependent macroscopic dielectric response $ε^M(ω)$ of metamaterials made of natural constituents with any geometrical shape repeated periodically with any structure. We illustrate the formalism calculating $ε^M(ω)$ for several structures. For dielectric rectangular inclusions within a conducting material we obtained a very anisotropic response which changes along one direction from conductor-like at low $ω$ to a resonant dielectric-like at large $ω$, attaining a very small reflectance at intermediate frequencies unrelated to surface plasmon excitation and which can be tuned through geometrycal tayloring. A similar behavior is obtained for other shapes close to the percolation threshold.