Uniaxial indefinite material formed by helical-shaped wires
Morgado, T. A.
Maslovski , S.
Silveirinha, M. G.
New Journal of Physics Vol. 14, Nº 063002, pp. 1 - 23, June, 2012.
ISSN (print): 1367-2630
ISSN (online): 1367-2630
Journal Impact Factor: 3,558 (in 2014)
Digital Object Identifier: 10.1088/1367-2630/14/6/063002
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We demonstrate that a racemic array of helical-shaped metallic wires may be regarded as a local uniaxial epsilon-negative (ENG) material even when the metal conductivity is very large (e.g. in the microwave regime) and, as a result, enables strong negative refraction over a wide frequency range. Based on the negative refraction effect, we demonstrate partial focusing of p-polarized electromagnetic radiation using a planar lens formed by such a composite material. The results reported here are supported by full-wave simulations as well as by analytical calculations based on effective medium theory.