  It is demonstrated that a structured material formed by nonconnected crossed
metallic wires may enable negative refraction over a wide frequency range. This
phenomenon is a consequence of the anomalous dispersion characteristics of the
material, particularly of the fact that the isofrequency contours are
hyperbolic. These properties rely on the nonlocal response of the crossed wire
mesh, and establish a different paradigm for obtaining negative refraction
without left-handed materials.
