Antenna applications of negative refraction parabolic lens of subwavelength hole arrays

A planoconcave parabolic lens exhibiting a negative index has been fabricated by using stacked subwavelength hole arrays as a route to build a metamaterial operating at millimeter wavelengths. The design consists of a staircase approximation of the ideal parabola profile by removing step by step one lattice in each dimension of the transversal section. Theory predicts power concentration at the focal point of the parabola when the refractive index equals -1. The possibility to employ these structures in antennas remains open.