Étude numérique des antennes épaisses par l’équation intégrale d’Albert et Synge
Résumé
The Albert and Synge integral equation allows to determine the current on a rotationnally symmetric conducting antenna of arbitrary meridian shape in the emission mode. This equation is deduced from the use of generalized boundary conditions and therefore possesses a regular kernel. This regularity is a cause of a numerical ill-conditionning of the linear systems deduced from such equations by use of moments methods. An iterative algorithm of inversion due to Le Foll allows to overcome the difficulties linked with this illconditionning. Computations have been made on various structures (spheres, cylinders with or without sharp edges, ...) and their validity has been checked from results already available or by comparison with experimental ones. Therefore such integral approach appears particularly interesting in the case of thick structures, the longitudinal or transversal dimensions of which may attain a few wavelengths. Such structures are useful in many domains. The development of wide bandwidth electromagnetic sensors, the coupling of active or passive devices from the millimeter waves up to the infrared are two important exemples.