Reconfigurable-focus flat lens based on gradient index metamaterials

Publisher: IOP Publishing

E-ISSN: 2040-8986|17|8|85103-85108

ISSN: 2040-8986

Source: Journal of Optics, Vol.17, Iss.8, 2015-08, pp. : 85103-85108

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Abstract

We propose a reconfigurable-focus flat lens based on a gradient index metamaterial, which is composed of metal hole arrays incorporated with varactor diodes and is able to transform a plane wave into a cylindrical wave. The transmission phase of each metal hole array is modified by changing the width of the rectangular holes. With the gradient transmission phase along the lateral direction of a flat lens, a plane wave can be transformed into a cylindrical wave. By delicately designing the capacitance of varactor diodes, the focus length of a flat lens can be reconfigured by 1.3 cm. Furthermore, the focusing performance of a flat lens is still preserved for oblique incidence.