Coifman wavelets in 3-D scattering from a calibration target consisting of doubly periodic sharp metal cones

The magnetic field integral equation (MFIE) is solved by Coiflet-based Galerkin's procedure in conjunction with the Floquet theorem for plane wave scattering from a doubly periodic array of sharp conducting circular cones. To avoid using intervallic wavelets to handle the boundary truncations, we split the unknown surface current into four components enforcing periodic boundary conditions, so that the standard Coiflets can be employed. Owing to the orthogonality, compact support, continuity and smoothness of the Coiflets, well-conditioned impedance matrices are obtained at the resolution level 5. Majority of the matrix entries are obtained in the spectral domain by one-point quadrature with high precision in O(h⁵), imposing the Dirac-δ property of the Coiflets. For the self elements and elements associated with the same elevation of the field and source points, z=z′, spatial domain computation is applied, bypassing the slow convergence of the spectral summation of the non-damping propagating modes. The simulation results of induced current and far-zone scattering pattern are compared with the solutions from an RWG-MLFMA based commercial software, FEKO, and excellent agreement is observed.