Adaptive Supersampling of Rays for Accurate Calculation of Physical Optics Scattering From Parametric Surfaces

Parallel body‐shaping of electrically large objects described by NURBS surfaces

“…As the fins and cylinder form a concave corner similar to a dihedral, multiple reflections have to be considered to improve the accuracy. For grazing incidence of impinging rays, adaptive supersampling has been used 19 . The monostatic RCS of the object is calculated by the authors' codes (labeled as MATLAB‐PO) and compared with the results of PO solver of CST in Figure 4.…”

“…1 For higher-order reflections inside the object segments, the ray-surface resolution mismatch affects the accuracy of determining S i . 19 The presence of r 0 and b n r 0 ð Þ in Equation (2) also complicates the numerical calculation of the physical optics integral. When NURBS surfaces are used to accurately describe the object, these challenges have to be carefully addressed.…”

“…For grazing incidence of impinging rays, adaptive supersampling has been used. 19 The monostatic RCS of the object is calculated by the authors' codes (labeled as MATLAB-PO) and compared with the results of PO solver of CST in Figure 4. As observed, the result of MATLAB-PO agrees well with CST result especially by considering the second-order reflection.…”

“…Such nonlinear equation systems should be solved by iterative methods, which are time‐consuming and may not even converge to the solution 1 . For higher‐order reflections inside the object segments, the ray‐surface resolution mismatch affects the accuracy of determining S i 19 . The presence of r ′ and in Equation () also complicates the numerical calculation of the physical optics integral.…”

“…This approximation has several advantages: Ray‐surface nonlinear equation system reduces to 2 × 2 linear equation system with analytical solution; Adaptive super‐sampling 19 can be incorporated to efficiently calculate the illuminated area of higher‐order reflections; Ludwig's integration method 21 with analytical formula can be used to calculate the physical optics integral on each mesh. …”