volume | PIER Journals

2015-08-11

Diffraction Calculation of Arbitrarily Curved Wedge Modeled with NURBS Surfaces

Jun Yan,

Dr. Jun Yan

Department of Microwave Engineering, School of Electronic Engineering

University of Electronic Science and Technology of China

China

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Jun Hu,

Prof. Jun Hu

University of Electronic Science and Technology of China

China

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Huapeng Zhao,

Dr. Huapeng Zhao

University of Electronic Science and Technology of China

China

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Zai-Ping Nie

Professor Zai-Ping Nie

School of Electric Engineering

University of Electric Science and Technology of China

China

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Progress In Electromagnetics Research M, Vol. 43, 63-70, 2015

doi:10.2528/PIERM15070605 | Google Scholar

Abstract

In this paper, we present an equivalent current-based numerical routine for calculating the diffraction of arbitrarily curved wedge modeled with non-uniform rational B-spline (NURBS) curves and surfaces. The NURBS curves and surfaces obtained from CAD systems need to be parameterized for numerical calculation; however, available parameterizing approaches in rendering computer graphics, which use straight line segments and flat facets for tessellation, are not suitable for the computation of the wedge diffraction. To make the full use of NURBS modeling technique in high-frequency asymptotic approaches, the proposed numerical routine utilizes a curvature adaptive tessellation scheme to parameterize the edge curve of the wedge with varying curvature as well as the method of parameter alignment to maintain the C0 continuity between the edge curve and the wedge surfaces, which is essential in evaluating the diffraction coefficients. Based on the proposed parameterizing method, the equivalent edge current can be implemented for diffraction computation of arbitrarily curved wedge modeled with NURBS curves and surfaces, complementing with the NURBS based physical optics (PO) as a fully NURBS-based high-frequency approach, which provides high geometrical accuracy and computational efficiency for calculating diffraction of electrically large curved wedges. Numerical examples are presented to validate the proposed method.

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Jun Yan, Jun Hu, Huapeng Zhao, and Zai-Ping Nie, "Diffraction Calculation of Arbitrarily Curved Wedge Modeled with NURBS Surfaces," Progress In Electromagnetics Research M, Vol. 43, 63-70, 2015.
doi:10.2528/PIERM15070605

References

1. Perez, J. and M. F. Catedra, "Application of physical optics to the RCS computation of bodies modeled with NURBS surface," IEEE Transactions on Antennas and Propagation, Vol. 42, No. 10, 1404-1411, 1994.
doi:10.1109/8.320747 Google Scholar

2. Dominingo, M., F. Rivas, J. Perez, R., P. Torres, and M. F. Catedra, "Computation of the RCS of complex bodies modeled using NURBS surfaces," IEEE Antennas and Propagation Magazine, Vol. 37, No. 6, 36-47, 1995.
doi:10.1109/74.482030 Google Scholar

3. Zhao, Y., X.-W. Shi, and L. Xu, "Modeling with NURBS surfaces used for the calculation of RCS," Progress In Electromagnetics Research, Vol. 78, 49-59, 2008.
doi:10.2528/PIER07082903 Google Scholar

4. De Adana, F. S., I. G. Diego, O. G. Blanco, P. Lozano, and M. F. Catedra, "Method based on physical optics for the computation of the radar cross section including diffraction and double effects of metallic and absorbing bodies modeled with parametric surfaces," IEEE Transactions on Antennas and Propagation, Vol. 52, No. 12, 3295-3303, 2004.
doi:10.1109/TAP.2004.836444 Google Scholar

5. Wang, N. X., J. Dang, H. B. Yuan, and C. H. Liang, "Study on curved wedge diffraction in NURBS-UTD method," Microwave and Optical Technology Letters, Vol. 55, No. 10, 2317-2321, 2013.
doi:10.1002/mop.27868 Google Scholar

6. Balazs, A., M. Guthe, and R. Klein, "Efficient trimmed NURBS tessellation," Journal of WSCG, Vol. 12, No. 1–3, 2004. Google Scholar

7. Chen, X., S. Y. He, D. F. Yu, H. C. Yin, W. D. Hu, and G. Q. Zhu, "Geodesic computation on NURBS surfaces for UTD analysis," IEEE Antennas and Wireless Propagation Letters, Vol. 12, 194-197, 2013.
doi:10.1109/LAWP.2013.2245291 Google Scholar

8. Michaeli, A., "Equivalent edge currents for arbitrary aspects of observation," IEEE Transactions on Antennas and Propagation, Vol. 32, No. 3, 252-258, 1984.
doi:10.1109/TAP.1984.1143303 Google Scholar

9. Boehm, W., "Generating the Bezier points of B-spline curves and surfaces," Computer Aided Design, Vol. 13, No. 32, 356-366, 1981. Google Scholar

10. Farin, G., Curves and surface for CAGD, Morgan Kaufmann, 2004.

11. Yan, J., J. Hu, and Z. P. Nie, "Calculation of the physical optics scattering by trimmed NURBS surfaces," IEEE Antennas and Wireless Propagation Letters, Vol. 13, 1640-1643, 2014.
doi:10.1109/LAWP.2014.2348564 Google Scholar