Finite element solution for scatterers with unbounded geometries

The class of scattering geometries that comprise a metallic cavity embedded in a perfectly conducting wedge is discussed. The absorbing boundary conditions (ABCs) approximate the behavior of outgoing waves only; consequently, these available ABCs are at a particular disadvantage when dealing with unbounded scatterers, for which the wave becomes outgoing except in the infinite limit. An additional difficulty with these scatterers is that the asymptotic behavior of their scattered field cannot be predicted a priori. To circumvent these difficulties, the combination of the surface integral equation approach with the finite element method is proposed. The versatility and validity of the surface integral equation technique are demonstrated. The bistatic and monostatic radar cross sections were calculated and found to compare favorably with results obtained using other methods.<>