Terahertz epsilon-near-zero graded-index lens
Víctor Torres, Víctor Pacheco-Peña, Pablo Rodríguez-Ulibarri, Miguel Navarro-Cía, Miguel Beruete, Mario Sorolla, Nader Engheta
Volume: 21, Issue: 7, 8 April 2013
9156 - 9166
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.
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