Couplage Equations de Maxwell - Potentiels Retardes pour les
Milieux Heterogenes  

Toufic ABBOUD
Centre de Mathematiques Appliquees - CNRS URA 756
Ecole Polytechnique, 91128 Palaiseau Cedex, France.
&
IMACS - Ingenierie Mathematiques et Calcul Scientifique
Ecole Polytechnique, 91128 Palaiseau Cedex, France.


&
Toni SAYAH 
IMACS - Ingenierie Mathematiques et Calcul Scientifique 
Ecole Polytechnique, 91128 Palaiseau Cedex, France.



Abstract :

We solve the problem of the scattering of a transient electromagnetic wave 
by a bounded heterogeneous medium in R^3 by the coupling of  the Boundary 
Element Method  and the Volumic Element Method. We first use the Retarded 
Potential Representation to reduce the PDE problem to an integro-differential 
problem posed in a bounded domain~: the heterogeneous obstacle + the interface
with the exterior domain. Then, we write this problem in a variational form 
that we approximate using finite elements in both time and space domains. 
That leads to a stable constructive numerical scheme. Finally, as a numerical 
example, we compare the exact and the computed RCS of a perfectly conducting 
sphere coated by a dielectric material. 


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