Finite-element solution of the problem of scattering from cavities in metallic screens using the surface integral equation as a boundary constraint.

This work presents a novel finite-element solution to the problem of scattering from multiple two-dimensional cavities in infinite metallic walls. The technique presented here is highly efficient in terms of computing resources and is versatile and accurate in comparison with previously published methods. The formulation is based on using the surface integral equation with the free-space Green's function as the boundary constraint. The solution space is divided into local bounded frames containing each cavity. The finite-element formulation is applied inside each frame to derive a linear system of equations associated with nodal field values. The surface integral equation is then applied at the opening of the cavities to truncate the computational domain and to connect the matrix subsystem generated from each cavity. The near and far fields are generated for different single and multiple cavity examples. The results are in close agreement with methods published earlier.