2000 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

IEEE Transactions on Antennas and Propagation
Volume 48 Number 6, June 2000

Table of Contents for this issue

Complete paper in PDF format

Extensions to the Hybrid Method of Moments/Uniform GTD Formulation for Sources Located Close to a Smooth Convex Surface

Isak P. Theron, Member, IEEE David B. Davidson, Member, IEEE and Ulrich Jakobus Member, IEEE

Page 940.

Abstract:

In this paper, we present an extension to the uniform geometrical theory of diffraction (GTD) for reflection from smooth curved surfaces. This approach allows the source to be much closer to the reflecting surface than the conventional uniform GTD formulation and does not require a Hertzian dipole source. In essence, the field point is mirrored in the plane tangential to the specular (reflection) point; the incident field is then calculated at the mirror point and the uniform GTD reflection coefficients are used to mirror this field to the original field point. This formulation reduces exactly to the conventional uniform GTD if the incident field is ray optical. The application to a hybrid method of moments (MoM)/GTD code is outlined and results computed using this code are presented for a dipole radiating in the vicinity of a cylinder.

References

  1. G. A. Thiele and T. H. Newhouse, "A hybrid technique for combining moment methods with the geometrical theory of diffraction", IEEE Trans. Antennas Propagat., vol. AP-23, pp.  62-69, Jan.  1975.
  2. U. Jakobus and F. M. Landstorfer, "A combination of current-and ray-based techniques for the efficient analysis of electrically large scattering problems", in Proc. 13th Annu. Rev. Progress Appl. Computat. Electromagn., Monterey, CA, Mar. 1997, pp.  748-755. 
  3. P. H. Pathak, W. D. Burnside and R. J. Marhefka, "A uniform GTD analysis of the diffraction of electromagnetic waves by a smooth convex surface", IEEE Trans. Antennas Propagat., vol. AP-28, pp.  631-642, Sept.  1980.
  4. P. H. Pathak, "High frequency techniques for antenna analysis", Proc. IEEE, vol. 80, pp.  44-65, Jan.  1992.
  5. H.-T. Chou, P. H. Pathak and M. Hsu, "Extended uniform geometrical theory of diffraction solution for the radiation by antennas located close to an arbitrary, smooth, perfectly conducting, convex surface", Radio Sci., vol. 32, pp.  1297-1317,  July-Aug.  1997.
  6. R. F. Harrington, Field Computation by Moment Methods, New York: IEEE Press, 1993.
  7. M. Hsu, "Hybrid (MM-UTD) analysis of EM scattering by finned objects", Ph.D. dissertation, Dept. Elect. Eng., The Ohio State Univ., 1995.
  8. D. A. McNamara, C. W. I. Pistorius and J. A. G. Malherbe, Introduction To The Uniform Geometrical Theory Of Diffraction, Norwood, MA: Artech House, 1990.