Computation of PO integral on trimmed NURBS surface for electromagnetic scattering prediction

The computation of physical optics (PO) integral on the trimmed Non-uniform rational B-spline (NURBS) surface is studied in this work. Unlike in the conventional NURBS-based PO method which requires the NURBS surface for PO integral should be defined in a rectangular parameter domain, the trimmed NURBS surface provides a non-rectangular parameter domain which is enclosed by a set of trimming contours. A trimmed region classification technique is thus proposed to overcome the problem. By the proposed technique, suitable regions on the trimmed NURBS surface for the PO integral calculation can be obtained. Numerical results demonstrate the effectiveness of the proposed method.