An Accurate and Efficient Hybrid Method for Calculating Electromagnetic Scattering from Honeycomb Sandwich Composite Structure

An accurate and efficient method for calculating electromagnetic scattering from honeycomb sandwich composite structure using hybrid finite element and multilayer surface integral equations (FE-MSIE) is proposed in this paper. In composite structures, the middle honeycomb core structure is modeled using finite element method, while the remaining uniform dielectric structures are modeled using surface integral equations method. To overcome the multiscale problem caused by the extremely thin honeycomb wall, the impedance boundary conditions (IBC) are introduced in the finite element method to simplify the honeycomb wall into a zero-thickness surface. The domain of MSIE adopts the discontinuous Galerkin method to improve the flexibility of modeling. In the iterative solution of the final matrix system, the multilevel fast multipole algorithm (MLFMA) is used to accelerate computation and reduce memory costs.