The transmission-line paradigm for metamaterials: Fundamentals & applications

This paper summarizes some of the recent advances in planar transmission-line metamaterials. First the issue of spatial harmonics excited in negative-refractive-index transmission-line (NRI-TL) is examined. It is shown that the fundamental backward-wave harmonic becomes dominant under the long wavelength regime. Subsequently the issue of the independent excitation of complex modes in a microstrip / NRI-TL coupler is examined. Finally it is explained how to synthesize suitable anisotropic transmission-line metamaterials for ‘transformation optics’ applications such as cloaking.