An Efficient Preconditioning Approach for Surface MLFMA Solution of Scattering from Multilayer Dielectric Bodies

The surface integral solution of scattering from multilayer dielectric bodies is studied in this letter. It is found that the matrix structure of discretized formulation for multilayer dielectric bodies has essential differences from that for homogeneous bodies since the formulation of multilayer dielectric bodies includes the interaction between equivalent currents on different interfaces. The previous efficient preconditioners for solution of homogeneous bodies are not efficient anymore or cannot be directly extended for solution of multilayer dielectric bodies. An efficient preconditioning approach is designed for multilayer dielectric bodies in this letter by recursively employing the Schur complement approximation and lower triangular approximation. The multilevel fast multipole algorithm is employed to further speed up the solution of multilayer dielectric problems. A series of numerical results are presented to show the capability of the preconditioning approach for multilayer bodies, especially for lossless large multilayer radomes.