Electromagnetic response of a structured drude material; a numerical study

In this work we have numerically investigated the electromagnetic response of a 2-dimensional nanostructured material with a Drude dispersive dielectric constant. The system consists in a square lattice of rings with a small positive dielectric constant realized in a material with negative permittivity. For certain frequencies of the exciting electromagnetic field, the nanostructured system presents a resonance which leads to a Lorentz type response. By performing finite difference time domain (FDTD) simulations and S-parameter calculations we have calculated the effective permittivity and permeability for this system.