Subwavelength focusing using a negative-refractive-index transmission line lens

We report simulations demonstrating subwavelength focusing of electromagnetic waves, from one homogeneous and isotropic dielectric to another, through a flat lens made of a realizable negative-refractive-index (NRI) metamaterial. The NRI metamaterial consists of a two-dimensional inductor/capacitor (L/C) loaded transmission line (TL) network in a dual (high-pass) configuration. The microwave-circuit simulation results presented show that the voltage at the focal plane is identical to that at the source plane. The results confirm that, in addition to focusing propagating waves, evanescent waves are also restored at the focal plane by the proposed loaded TL lens, thus enhancing the resolution of the image. In addition, the nature of the voltage distribution (vertical electric field) in this "perfect-focusing" setup is clarified.