Growing evanescent waves in negative-refractive-index transmission-line media

We show the enhancement of evanescent waves by a realizable negative-refractive-index (NRI) medium consisting of a periodic 2-D L,C loaded transmission-line (TL) network. This network is referred to as a dual TL structure. Growing evanescent waves within the dual TL structure are predicted analytically and demonstrated through simulation. These findings confirm that the dual TL structure is not simply a phase compensator that corrects the phase of propagating waves, but is in fact a NRI medium, since it also enhances the amplitudes of evanescent waves. This structure is a likely candidate for microwave subwavelength focusing and imaging applications.