Experimental Verifications of Left-Handed Characteristics of 3-D Left-Handed Metamaterial Composed of Periodic Wired Metallic Spheres

摘要

The left-handed (LH) operation of a three-dimensional (3-D) LH material composed of wired metallic spheres is experimentally confirmed. A 15 x 15 x 3-cell periodic structure designed to have an isotropic LH characteristics is fabricated by a 3-D printer with post plating technology, and near-field measurements of refracted waves by the negative refractive index slab lens are carried out. The dispersion characteristics measured from the near-field distributions on the surface of the LH material clearly show that the structure supports the backward waves at 12 GHz band. It is also shown experimentally that the resolution of the slab lens exceeds the diffraction limit by near field measurements with a single source and adjacent two sources. In addition, near-field measurements from the LH material near the T-point frequency at 12.90 GHz are carried out. A highly directive plane wave with a single point source is observed and the near-zero-index operation has been confirmed.