A time domain uniform gometrical theory of slope diffraction for a curved wedge
A time domain uniform gometrical theory of slope diffraction for a curved wedge
A time domain version of the uniform geometrical theory of diffraction (TD-UTD) is developed to describe, in essentially closed form, the field which is produced via slope diffraction at a perfectly conducting, arbitrarily curved wedge excited by a time impulsive wave that exhibits a rapid spatial variation near the edge of the wedge. This TD-UTD slope diffracted field for a curved wedge is obtained by a Fourier inversion of the corresponding frequency domain UTD expression. An analytical signal representation of the transient fields is used since it is convenient, and because it circumvents some of the difficulties, which especially arise when inverting into time domain the frequency domain UTD fields associated with rays that have traversed caustics. The TD-UTD slope diffraction solution is obtained in a manner analogous to that utilized to develop an earlier TD-UTD solution, presented by the authors, for the case when the incident field does not exhibit a rapid spatial variation at the edge [1]. This TD-UTD slope diffraction solution for a time impulsive incident field can also be used for dealing with relatively general pulsed excitations via an efficient convolution procedure similar to that in [1]. Numerical results are presented to illustrate the accuracy of the TD-UTD solution by comparing it to the exact solution for a straight wedge with pulsed excitation, which was obtained earlier by Felsen [13].
___
- [1] P. R. Rousseau and P.H. Pathak, "Time-Domain Uniform Geometrical Theory of Diffraction for a Curved • Wedge," IEEE Trans. AP-43, No. 12, December. 1995, pp. 1375-1382.
- [2] E. Heyman and L. B. Felsen, "Weakly Dispersive Spectral Theory of Transients (STT), Part I: Formulation and Interpretation," IEEE Trans. AP, vol. AP-35, pp. 80-86, January 1987.
- [3] E. Heyman and L. B. Felsen, "Weakly Dispersive Spectral Theory of Transients (STT), Part II: Evaluation of the Spectral Integral," IEEE Trans. AP, vol. AP-35, pp. 574-480, May 1987.
- [4] E. Heyman, "Weakly Dispersive Spectral Theory of Transients (STT), Part III: Applications," IEEE Trans.AP, vol. AP-35, pp. 1258-1987, November 1987.
- [5] E. Heyman and R. Ianconescu, "Pulsed Field Diffraction by a Perfectly Conducting Wedge: Local Scattering Models," IEEE Trans. AP, vol. 43, pp. 519-528, May 1995.
- [6] R. Ianconescu and E. Heyman, "Pulsed Field Diffraction by a Perfectly Conducting Wedge: Exact Solution,"IEEE Trans. AP, vol. 42, pp.1377-1385, October 1994.
- [7] R. Ianconescu and E. Heyman, "Pulsed Field Diffraction by a Perfectly Conducting Wedge: A Spectral Theory of Transients Analysis," IEEE Trans. AP, vol. 42, pp., 781-789, June 1994.
- [8] P. R. Rousseau, "Time Domain Version of the Uniform Geometrical Theory of Diffraction," Ph.D. Dissertation, Dept. of Electrical Engineering, The Ohio State University, Columbus, Ohio, 1995.
- [9] Y. M. Hwang and R. G. Kouyoumjian, "A Dyadic Diffraction Coefficient for an Electromagnetic Wave Whichis Rapidly Varying at an Edge,"USNC-URSI, 1974. Presented at the USNC-URSI Annual Meeting, Boulder, CO, October, 1974.
- [10] T. Veruttipong. "Diffraction at Edges and Convex Surfaces Illuminated by Fields with a Rapid Spatial Variation," Ph.D. Dissertation, Dept. of Electrical Engineering, The Ohio State University, Columbus, OH 1982.
- [11] O. M. Buyukdura, "GTD Solution With Higher Order Terms to the Diffraction by an Edge: Towards a Uniform Solution," IEE Proc. Microw., Antennas, Propag., vol. 143, pp. 43-50, 1996.
- [12] O. Breinbjerg, "A Slope Diffraction Coupling Effect," Electomagnetics (special issue on the centennial of Sommerfeld's diffraction problem), vol. 18, No. 2, pp. 179-206, March 1998.
- [13] L. B. Felsen and N. Marcuvitz, Radiation and Scattering of Waves. Englewood Cliffs, NJ: Prentice Hall, 1973.
- [14] R. G. Kouyoumjian and P.H. Pathak, "A Uniform Geometrical Theory of Diffraction for an Edge in a Perfectly Conducting Surface," Proc. IEEE, vol. 62, pp. 1448-1461, November 1974
- [15] P. H. Pathak, "Techniques for High Frequency Problems," Antenna Handbook: Theory, Application and Design (Y.T. Lo and S.W. Lee, eds.), ch. 4, Van Nostrand Reinhold Company, 1988.
- [16] P. H. Pathak, "High Frequency Techniques for Antenna Analysis," Proc. IEEE, vol. 80, pp. 44-65, January 1992.
- [17] D. Zheng, "A Modified Slope Diffraction for a Curved Wedge or Screen," M.S. Thesis, Dept. of Electrical Engineering, The Ohio State University, Columbus, Ohio, 1985.
- ISSN: 1300-0632
- Yayın Aralığı: Yılda 6 Sayı
- Yayıncı: TÜBİTAK
Sayıdaki Diğer Makaleler
A time domain uniform gometrical theory of slope diffraction for a curved wedge
Paul R. ROUSSEAU, Prabhakar PATHAK
Network-oriented modeling of radiating electromagnetic structures
2D complex point source radiation problem II. Complex beams
M. J. Gonzalez MORALES, E. GAGO-RIBAS
Floquet wave diffraction theory for tapered planar strip array Green's function