title: Transformation optics for antennas: why limit the bandwidth with metamaterials?
abstract: In the last decade, a technique termed transformation optics has been developed for the design of novel electromagnetic devices. This method defines the exact modification of magnetic and dielectric constants required, so that the electromagnetic behaviour remains invariant after a transformation to a new coordinate system. Despite the apparently infinite possibilities that this mathematical tool introduces, one restriction has repeatedly recurred since its conception: limited frequency bands of operation. Here we circumvent this problem with the proposal of a full dielectric implementation of a transformed planar hyperbolic lens which retains the same focusing properties of an original curved lens. The redesigned lens demonstrates operation with high directivity and low side lobe levels for an ultra-wide band of frequencies, spanning over three octaves. The methodology proposed in this paper can be applied to revolutionise the design of many electromagnetic devices overcoming bandwidth limitations.
authors.affiliation: School of Electronic Engineering and Computer Science, Queen Mary University of London, London, United Kingdom.
authors.forename: Oscar
authors.initials: O
authors.lastname: Quevedo-Teruel
authors.forename: Wenxuan
authors.initials: W
authors.lastname: Tang
authors.forename: Rhiannon C
authors.initials: RC
authors.lastname: Mitchell-Thomas
authors.forename: Amy
authors.initials: A
authors.lastname: Dyke
authors.forename: Hazel
authors.initials: H
authors.lastname: Dyke
authors.forename: Lianhong
authors.initials: L
authors.lastname: Zhang
authors.forename: Sajad
authors.initials: S
authors.lastname: Haq
authors.forename: Yang
authors.initials: Y
authors.lastname: Hao
mesh_terms: D003198:Computer Simulation; D055590:Electromagnetic Phenomena; D007909:Lenses; D015233:Models, Statistical; D055095:Optics and Photonics / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*