Résumé
The perfectly conducting infinite wire structure has been shown to exhibit negative effective permittivity (incidence normal to the wires), and strong spatial dispersion (in conical incidence) for wavelengths much larger than the wire separation. In this work we make use of a two-scale renormalization technique to treat the more general, realistic and practically relevant finite conductivity finite wire structure. The effective medium obeys a nonlocal constitutive relation which is verified by 3D numerical simulations.