Improved accuracy in the scattering analysis of infinitely long ferromagnetic objects

The scattering of transversal magnetic (TM) electromagnetic waves impinging on infinitely long homogeneous ferromagnetic objects is usually analyzed with the Poggio-Miller-Chan-Harrington-Wu-Tsai (PMCHWT) integral equation. The Method-of-Moments (MoM) discretization of TM-PMCHWT usually requires continuous piecewise linear basis functions. These basis functions are especially well suited in the analysis of single radar targets since they cancel out the hypersingular terms in the scattered magnetic field. However, the analysis of complex objects, with junctions or nonmatching segmentations, becomes particularly inconvenient because of the interelement continuity constraints. In this work, in order to provide enhanced versatility, we propose the discretization of the currents with discontinuous piecewise linear basis functions. Since the hypersingular Kernel contributions cannot be evaluated through a conventional Galerkin testing scheme, we propose two new testing procedures. We show the improved RCS-accuracy for this nonconforming discretization of TM-PMCHWT, with respect to traditional continuous piecewise linear discretization, for an example of infinitely long sharp-edged ferromagnetic cylinder.