A hybrid method for the analysis of scattering from electrically large objects with deep cavities

A hybrid technique is presented for the analysis of high frequency electromagnetic scattering from large structures with open cavities. The technique combines an efficient ray-based asymptotic method for the outer region with a full wave method for the cavity region. The coupling scheme is based on an exact formulation, where the cavity region is described by a generalized admittance matrix. This allows flexibility concerning the choice of an appropriate method to solve the cavity region. For the solution of the outer problem a ray-tube tracing method has been developed, which employs a triangular connection scheme and second-order field interpolations. The method allows an accurate GO field description with a relatively small number of rays particularly suited for curved surfaces with higher order field reflections. Diffraction effects are also taken into account. Numerical results are presented to demonstrate the accuracy and efficiency of the hybrid technique.