ABSTRACT
This chapter discusses experimental verifications of several lenses realized using the negative-refractive-index transmission-line (NRI-TL) approach and begins with a description of some of the first experimental demonstrations of focusing and subdiffraction imaging using planar NRI-TL metamaterials. NRI-TL metamaterials are known for their extremely broadband and low-loss negative refractive index (NRI) properties and are easy to construct. The phenomenon of free-space subdiffraction imaging, although not using Veselago–Pendry superlenses, has been experimentally demonstrated by many types of metamaterials. The chapter describes two such experiments in the planar regime. The first is a large NRI-TL metamaterial planar lens designed to demonstrate the property of focusing across a planar interface by measurements of field magnitudes and phases above the grid surface. The second is a NRI-TL metamaterial planar superlens, carefully designed according to the strict requirements of the Veselago–Pendry superlens to demonstrate focusing beyond the diffraction limit by the resonant enhancement of evanescent waves emanating from the source.
