Physical optics formulas for the scattering from metallic and dielectric plates with cubic spline curved boundaries

Closed-form expressions of the physical optics (PO) field scattered in the far zone by metallic and dielectric plates with cubic spline curved boundaries are derived in terms of incomplete cylindrical functions (ICFs). The developed expressions, in combination with PO formulas for the scattering from polygonal plates and conical-section boundary angular sectors or segments, can constitute a useful tool for an accurate and numerically efficient prediction of the radar cross section (RCS) of targets with complex shapes. Preliminary comparisons with completely numerical PO results are provided to demonstrate the correctness of these representations.