PMC

(a, b) Simulated phase (°) and normalized amplitude distributions, respectively; (c, d) Measured phase (°) and normalized amplitude distributions, respectively.

(a) Photo of a half-cut manufactured lens; (b) Photo of the final prototype; (c, d) Pictures of powders illustrating alternative size distributions: (c) micron sized and (d) nanosized material; (e) Frequency dependence of the dielectric permittivities of the employed materials.

(a) The Eilean Glas Light (1907): Lighthouse lens which makes use of the Fresnel Principle to focus the beam. Photograph taken by Dr. Oscar Quevedo-Teruel at the Science Museum of London; (b) Original Hyperbolic lens: D = 190 mm, F = D/4 = 47.5 mm and t = 29.5 mm; (c) Discrete coordinate transformation of the original shape; (d) Dielectric constant distribution for the new coordinate space.

(a–d) Measured 2D normalized far-field distribution (7, 10, 12 and 14 GHz, respectively); (e) Measured gain (with and without the transformed lens) and side lobe level at the lower band of operation (with the lens). (f) Simulated directivity for the original hyperbolic lens, transformed lens and Fresnel lens, all of them fed with an X-band waveguide at their focal point.