(Optical Society of America, 2013) Torres Landívar, Víctor; Pacheco-Peña, Víctor; Rodríguez Ulibarri, Pablo; Navarro Cía, Miguel; Beruete Díaz, Miguel; Sorolla Ayza, Mario; Engheta, Nader; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua, 055/01/11
An epsilon-near-zero graded-index converging lens with planar
faces is proposed and analyzed. Each perfectly-electric conducting (PEC)
waveguide comprising the lens operates slightly above its cut-off frequency
and has the same length but different cross-sectional dimensions. This
allows controlling individually the propagation constant and the normalized
characteristic impedance of each waveguide for the desired phase front at
the lens output while Fresnel reflection losses are minimized. A complete
theoretical analysis based on the waveguide theory and Fermat’s principle
is provided. This is complemented with numerical simulation results of
two-dimensional and three-dimensional lenses, made of PEC and
aluminum, respectively, and working in the terahertz regime, which show
good agreement with the analytical work.
