Scattering from 3-D cavities with a plug and play numerical scheme combining IE, PDE, and modal techniques

In this paper, we present a multidomain and multimethod coupling scheme cal led FACTOPO, based on generalized scattering matrix computations on three-d imensional (3-D) subdomains. The global target Omega is split in N-v subdom ains (V-i)(i=1), (NV), separated by N-I fictitious surfaces (Gamma(j))(j=1, NI). We use a modal representation of the tangent fields on the interfaces. In each domain, the generalized Scattering matrix S-i is computed with dif ferent methods such as the 3-D finite-element method (FEM) or the electric field integral equation (EFIE), This coupling scheme leads to an important reduction in computational resources, especially for cavities with one dime nsion much larger than the other two. The advantages of this formulation fo r parametric studies will be illustrated by two cases: computing the RCS of an air-intake terminated with a flat PEC or a fan (CHANNEL) and of an ante nna structure coupled to an electronic feed with a varying parameter (DENEB ), Numerical as well as experimental results are presented.