Applications du formalisme des faisceaux gaussiens à la modélisation de l'interaction d'une onde électromagnétique avec un objet 3D complexe

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Physics-based expansion on 3D conformal Gaussian beams for the scattering from a curved interface

International audienceGaussian beams techniques are high-frequency asymptotic methods that can be used to model the propagation/interaction of fields in a variety of problems. In this article, an expansion is proposed to express the scattering of magnetic/electric currents from a curved interface in terms of a new kind of elementary beams, the conformal Gaussian beams. The expansion characteristics rely on the physical properties of the configuration, which leads to represent the scattering with a small number of conformal Gaussian beams. An analytical formulation for the conformal Gaussian beams is developed, which expression is derived from an asymptotic evaluation of the radiation integrals valid at great distance from the interface. An example is presented to show that this analytical formulation is in good agreement with the reference result. Numerical tests are led on the expansion in order to show that the scattering can be represented with accuracy by adding the contribution of conformal Gaussian beams

Integration of Leaky and Surface Waves in a 2D Gaussian Beam Formalism for Antenna-Structure Coupling

Abstract—Gaussian beam techniques are efficient asymptotic methods for field radiation computation. In these techniques, the initial field is first expanded on a chosen surface in elementary Gaussian beams which can propagate and/or interact with surrounding structures. However, the expansion cannot take into account surface and leaky waves propagation. In this paper, we propose an appropriate hybridization method using surface equivalent currents to overcome this limitation. The equivalent current formulation is written on grounded dielectric slab in spectral domain and can model surface and leaky waves which propagate from the surface expansion. The hybridization is carried out on the expansion surface, on which the distribution of elementary Gaussian beams and equivalent currents must be chosen in a relevant way. We study the influence of hybridization parameters and define a set of them leading to good results for general cases. 1

Contribution à l'étude et la conception d'une antenne réseau à balayage électronique pour liaisons de données haut-débit entre un drone et un satellite en bande Ka

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Application of gaussian beam based techniques to the quasi-optical systems of radiofrequency radiometers

http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5505517&tag=1International audienceThe electromagnetic performances of the quasi-optical systems may be critical in the design of a mm-wave radiometer. We propose to compute these performances by means of gaussian-beam based techniques. Numerical and experimental tests reveal a good trade-off between the accuracy and the computational effort

2D interaction of a gaussian beam with a dichroic surface for the modeling of quasi-optical systems

International audienceOne solution to model quasi-optical system - systems generally constituted by elements of large dimension with respect to the wavelength - is to use asymptotics, such as Gaussian Beams (GB) based techniques [1]. In these systems, dichroic surfaces are used to split, filter or mix an input signal. However, these surfaces are generally made of periodic elements of size that does not exceed a fraction of wavelength. Therefore, they cannot be modeled by such methods. In this paper we propose a technique, based on a spectral representation, to treat the interaction of a GB with a dichroic surface, we suppose that the fields reflected and transmitted by the interface can be approximated by GBs

A 2D Gaussian-Beam-Based Method for Modeling the Dichroic Surfaces of Quasi-Optical Systems

International audienceIn this article, we propose an approach in the spectral domain to treat the interaction of a field with a dichroic surface in two dimensions. For a Gaussian beam illumination of the surface, the reflected and transmitted fields are approximated by one reflected and one transmitted Gaussian beams. Their characteristics are determined by means of a matching in the spectral domain, which requires a second-order approximation of the dichroic surface response when excited by plane waves. This approximation is of the same order as the one used in Gaussian beam shooting algorithm to model curved interfaces associated with lenses, reflector, etc. The method uses general analytical formulations for the GBs that depend either on a paraxial or far-field approximation. Numerical experiments are led to test the efficiency of the method in terms of accuracy and computation time. They include a parametric study and a case for which the illumination is provided by a horn antenna. For the latter, the incident field is firstly expressed as a sum of Gaussian beams by means of Gabor frames

Gaussian beams for quasi-optical-systems: Modeling dichroic surfaces near a zero of transmission or reflection

International audienceGaussian-beam based methods are well-known for modeling quasi-optical systems constituted by mirrors, lenses, and horn antennas. In this article, a solution is proposed to include dichroic surfaces while maintaining the Gaussian-beam formulation. Special attention is devoted to the case where the dichroic surface response presents a zero near the angle of incidence. Numerical experiments are led on a dielectric slab to show the efficiency of the method

Interaction 2D d'un faisceau gaussien avec une surface dichroïque pour la modélisation de systèmes quasi-optiques

National audienceUne des solutions pour modéliser des systèmes quasi-optiques, dispositifs comportant divers éléments dont des surfaces dichroïques, est d'utiliser des techniques asymptotiques comme celles basées sur les faisceaux gaussiens. Or, les surfaces dichroïques sont pour certaines composées d'éléments périodiques de dimension inférieure à la longueur d'onde, ce qui n'est actuellement pas modélisable par de telles méthodes. Nous proposons dans cet article une technique permettant de traiter l'interaction d'un faisceau gaussien avec une surface dichroïque. Pour ce faire, nous supposons qu'un faisceau incident donne naissance à deux faisceaux, un transmis et un réfléchi, dont les caractéristiques sont modifiées. Les résultats de cette technique sont ensuite comparés numériquement à la méthode des moments (MoM)