Computation of the Physical Optics Integral on T-spline Surfaces

The radar scattering cross section (RCS) is an essential parameter for describing radar target characteristics. The geometric modeling of targets and the implementation of the electromagnetic high-frequency algorithm have a crucial influence on the precision and speed of the calculation results. This paper presents a method for calculating the far-field RCS of a T-spline-modeled ideal conductor using the physical optics (PO) method. After recognizing the limitations of conventional target description methods, alternative solutions based on non-uniform rational B-spline (NURBS) surfaces are presented. The small number of NURBS surface control points can reduce memory requirements and calculation time. On complex objects, however, the unevenness of the structural lines and the discontinuity of splicing are encountered. T-spline is a new geometric modeling technique that effectively compensates for the inaccuracies, structural integrity, and stitching issues of NURBS. T-spline modeling has the benefits of seamless data compression, which allows for a significant reduction in the number of control points and the complex target can be calculated as a whole. In the calculation of RCS, the physical optical integral on the surface of the scattering body is transformed by means of parameters into the integral on the parameter field. In this paper, the formula for calculating the scattering field and the far-field RCS results of an ideal conductor composed of a T-spline model is derived. The experimental results are compared with the results obtained by FEKO, and the results are consistent, indicating that the proposed approach is effective.