Measurements of a 3-D negative refractive index slab lens composed of periodic wired metallic spheres

Near field measurements of refracted waves by a three-dimensional (3-D) negative refractive index slab lens are carried out. The 3-D structure is composed of periodic unit cells with face-centered cubic lattice with metallic spheres connected by a metallic wire at the center of the lattice. Measured electric field distributions with a single source clearly show negative refraction characteristics which coincide with designed dispersion characteristics. It is also shown experimentally that the resolution of the slab lens exceeds the diffraction limit by near field measurements with adjacent two sources.