Planar metamaterial guiding from the perspective of geometrically induced surface plasmons

Engineering concepts such as input impedance of a transmission line and equivalent circuit models are shown to be simple, yet effective tools to design surface waves-like plasmons for planar guiding with subwavelength confinement. Moreover, these well-known concepts allow merging together plasmonics and metamaterials under an engineering perspective, which may bring a wide range of possibilities to alleviate limitations of each field. As a proof of principle, classical geometrically induced surface plasmons have been analysed from this prism and correlated to their dispersion diagrams. Finally, a complementary split-ring resonantors-based configuration has been proposed leading to energy in- and out-of-plane confinement improved with respect to classical proposals.