A Hybrid SESI Method for Electromagnetic Scattering by Objects in Multiregion Cylindrically Layered Media

An efficient and accurate hybrid spectral element-spectral integral (SESI) method is proposed to simulate electromagnetic (EM) scattering by objects in multiregion cylindrically layered media. The field in each of the multiple regions with multiple scatterers can be solved by the spectral element method (SEM), while the spectral integral method (SIM) is used as an exact boundary condition for the adjacent regions with multilayered media. This boundary condition between the electric field and the surface current density in each cylindrical layer can be obtained by using a recursive formula in SIM. The inverse matrix of a Toeplitz matrix arising from the SIM can be solved by the fast Fourier transform (FFT) with
$O(N\log N)$
complexity. The hybrid SESI method is used to simulate homogeneous and/or inhomogeneous multiregion multilayered structures. Numerical examples, including the frequency selective surface (FSS) applications, demonstrate that the hybrid SESI method is efficient and accurate by comparing its results with analytical solutions and results from the conventional SEM and the finite element method (FEM).