Ultra directive antenna via transformation optics

Spatial coordinate transformation is used as a reliable tool to control electromagnetic fields. In this paper, we derive the permeability and permittivity tensors of a metamaterial able to transform an isotropically radiating source into a compact ultradirective antenna in the microwave domain. We show that the directivity of this antenna is competitive with regard to conventional directive antennas horn and reflector antennas, besides its dimensions are smaller. Numerical simulations using finite element method are performed to illustrate these properties. A reduction in the electromagnetic material parameters is also proposed for an easy fabrication of this antenna from existing materials. Following that, the design of the proposed antenna using a layered metamaterial is presented. The different layers are all composed of homogeneous and uniaxial anisotropic metamaterials, which can be obtained from simple metal-dielectric structures. When the radiating source is embedded in the layered metamaterial, a highly directive beam is radiated from the antenn

Localization of light in a lamellar structure with left-handed medium : the light wheel

International audienceThe contra-directional coupling between a left-handed monomode waveguide and a right-handed monomode waveguide is rigorously studied using a complex plane analysis. Light is shown to rotate in this lamellar structure forming a very exotic mode which we have called a light wheel. The light wheel can be excited using evanescent coupling or by placing sources in one of the waveguides. This structure can thus be seen as a new type of cavity. It is a way to suppress the guided mode of a dielectric slab

Waveguide taper engineering using coordinate transformation technology

Spatial coordinate transformation is a suitable tool for the design of complex electromagnetic structures. In this paper, we define three spatial coordinate transformations which show the possibility of designing a taper between two different waveguides. A parametric study is presented for the three transformations and we propose achievable values of permittivity and permeability that can be obtained with existing metamaterials. The performances of such defined structures are demonstrated by finite element numerical simulations

Transformations electromagnetics and applications in the microwave and optics domain

Ce travail de thèse constitue une contribution originale et importante à la compréhension de la transformation d’espace et ouvre la voie au design de nouvelles structures éléctromagnétiques. Le couplage entre cette technique innovante et les métamatériaux a permis la réalisation de prototypes aux propriétés uniques. C’est ainsi que nous avons pu concevoir une cape d’invisibilité polygonale, un adapteur de modes ou encore une antenne directive ou isotrope. La fabrication de notre antenne très directive par cette méthode est le seul prototype dans la littérature qui allie le contrôle de la permittivité et la perméabilité à partir de résonnateurs électriques et magnétiques. Ce contrôle ultime de la lumière à partir d’une ingénierie de l’espace trouvera son utilité dans la recherche fondamentale mais aussi pour les ingénieurs et dévellopeurs recherchant plus de précision dans leur conception de dispositifs électromagnétiques.This phD work is an original and important contribution to the understanding of transformation optics and paves the way to the design of new electromagnetic structures. The coupling between this innovative technique and metamaterials has led to prototypes with unique properties. We have thus developed an invisibility polygonal cloak, an electromagnetic taper, a directional antenna and isotropic source. The realization of our high-directive antenna with this method is the only prototype in the literature that combines controlled variations of the permittivity and permeability from electric and magnetic resonators. The ultimate control of light from an engineering space will find its usefulness in fundamental research but also for engineers and developers who are looking for more precision in the design of electromagnetic devices

Transformations d'espaces et applications électromagnétiques dans les domaines optiques et micro-ondes

Ce travail de thèse constitue une contribution originale et importante à la compréhension de la transformation d espace et ouvre la voie au design de nouvelles structures éléctromagnétiques. Le couplage entre cette technique innovante et les métamatériaux a permis la réalisation de prototypes aux propriétés uniques. C est ainsi que nous avons pu concevoir une cape d invisibilité polygonale, un adapteur de modes ou encore une antenne directive ou isotrope. La fabrication de notre antenne très directive par cette méthode est le seul prototype dans la littérature qui allie le contrôle de la permittivité et la perméabilité à partir de résonnateurs électriques et magnétiques. Ce contrôle ultime de la lumière à partir d une ingénierie de l espace trouvera son utilité dans la recherche fondamentale mais aussi pour les ingénieurs et dévellopeurs recherchant plus de précision dans leur conception de dispositifs électromagnétiques.This phD work is an original and important contribution to the understanding of transformation optics and paves the way to the design of new electromagnetic structures. The coupling between this innovative technique and metamaterials has led to prototypes with unique properties. We have thus developed an invisibility polygonal cloak, an electromagnetic taper, a directional antenna and isotropic source. The realization of our high-directive antenna with this method is the only prototype in the literature that combines controlled variations of the permittivity and permeability from electric and magnetic resonators. The ultimate control of light from an engineering space will find its usefulness in fundamental research but also for engineers and developers who are looking for more precision in the design of electromagnetic devices.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Coordinate transformation applied to change physical appearance of radiating sources

International Symposium of the IEEE-Antennas-and-Propagation-Society, Orlando, FL, JUL 07-13, 2013International audienceThe use of transformation optics concept to change the physical size of radiating sources is investigated. By choosing transformations that compress space, and then match it to the surrounding radiation environment, we are able to miniaturize the physical size of the embedded source. We show that a small aperture antenna can then behave as one with a large aperture. A study of the transformation of the space metric and the material parameter calculation is presented. Simulations are performed to validate the proposed approach at microwave frequencies. This study paves the way to interesting applications in telecommunications and aeronautical domain

Engineering of source appearance via transformation optics concept

7th European Conference on Antennas and Propagation (EuCAP), Gothenburg, SWEDEN, APR 08-12, 2013International audienceThe use of transformation optics concept for the design of miniaturized radiating devices is investigated. By choosing transformations that compress space, and then match it to the surrounding radiation environment, we are able to alter the physical size of the embedded source. We show that a small aperture antenna can then behave as one with a large aperture. A study of the transformation of the space metric and the material parameter calculation is presented. Simulations are performed to validate the proposed approach at microwave frequencies. This study paves the way to interesting applications in telecommunications and aeronautical domain