GTD solution with higher order terms to the diffraction by an edge: towards a uniform solution

Buyukdura, O. Merih

doi:10.1049/ip-map:19960117

Cited by 10 publications

(5 citation statements)

References 3 publications

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“…Also, when the evanescence angle does not vanish, they exhibit a jump discontinuity at the SBs, which must compensate the corresponding discontinuity in the evanescent GO field. When ψ = 0 (homogeneous incident plane wave), the extra diagonal terms are continouous at the SBs, as expected, but they are not smooth since they have to compensate a discontinuity in the derivative of the GO field [ Büyükdura , 1996].…”

Section: Numerical Resultsmentioning

confidence: 79%

“…In order to provide suitable asymptotic expressions also for the ρ and ϕ components of the diffracted field, can be substituted into , as suggested by Büyükdura [1996]. It follows that:

where the elements t ij of the 3 × 2 matrix T are given by

with

…”

Section: High‐frequency Asymptotic Analysismentioning

confidence: 99%

“…The ρ and ϕ components of the diffracted field in include a term of order k −1/2 plus other terms of higher‐order ( k −3/2 ) as already discussed by Büyükdura [1996] and by Kouyoumjian et al [1983], where the homogeneous plane wave incidence case is analyzed. In the above cited papers, it is shown that the introduction of higher‐order terms in the asymptotic analysis gives a solution for the diffracted field that not only compensates the jump discontinuities in the GO field but also the discontinuities in the GO field derivatives.…”

Section: High‐frequency Asymptotic Analysismentioning

confidence: 99%

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Inhomogeneous electromagnetic plane wave diffraction by a perfectly electric conducting wedge at oblique incidence

et al. 2007

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[1] The diffraction of an inhomogeneous electromagnetic plane wave obliquely incident on the edge of a perfectly conducting wedge is analyzed, to extend the results for the normal incidence case reported by Kouyoumjian et al. (1996). Uniform high-frequency expressions are obtained for the diffracted field in the format of the uniform geometrical theory of diffraction (UTD). The generalized dyadic diffraction coefficient in the standard UTD ray-fixed coordinate system is represented by a 2 Â 2 full matrix with the extradiagonal terms accounting for a coupling between the two components of the incident and diffracted electric field parallel and perpendicular to the edge-fixed incidence and diffraction plane, respectively. The latter characteristic of the diffraction matrix is due to both the vectorial properties of the evanescent incident electric field and the inclusion of higher-order terms in the asymptotic expression of the edge diffracted field. The introduction of higher-order terms in the asymptotic evaluation also guarantees an improved accuracy for smaller values of the large parameter, namely, for observation points closer to the diffracting edge, as compared with the ordinary UTD.Citation: Kouyoumjian, R. G., T. Celandroni, G. Manara, and P. Nepa (2007), Inhomogeneous electromagnetic plane wave diffraction by a perfectly electric conducting wedge at oblique incidence, Radio Sci., 42, RS6S06,

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Section: Numerical Resultsmentioning

confidence: 79%

“…In order to provide suitable asymptotic expressions also for the ρ and ϕ components of the diffracted field, can be substituted into , as suggested by Büyükdura [1996]. It follows that:

where the elements t ij of the 3 × 2 matrix T are given by

with

…”

Section: High‐frequency Asymptotic Analysismentioning

confidence: 99%

Section: High‐frequency Asymptotic Analysismentioning

confidence: 99%

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Inhomogeneous electromagnetic plane wave diffraction by a perfectly electric conducting wedge at oblique incidence

et al. 2007

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“…Here D s and D h are the UTD diffraction coefficients and the other terms are the higher order diffraction coefficients. It is noted that the above result is an exact solution for the diffraction for a half-plane [7].…”

Section: Derivation Of Dyadic Green's Function For a Wedge In Sphericmentioning

confidence: 67%

Last PhD supervised by Professor Kouyoumjian: Extended UTD by Dr. Buyukdura

Altintas

2011

2011 XXXth URSI General Assembly and Scientific Symposium

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While he is a Professor Emeritus at Ohio State, Professor Kouyoumjian supervised a thesis work by Merih Buyukdura. They first derived a dyadic Green's function for a PEC wedge using spherical wave functions and employed asymptotic approximation. They also derived the extended UTD in which higher order terms in the diffraction matrix are predicted. The thesis was defended in 1984. In this presentation, a brief discussion of edge waves as derived from the asymptotic expansion of dyadic Green's function in terms of spherical functions will be made and afterwards the derivation of extended UTD diffraction coefficients will be given. © 2011 IEEE

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“…The two versions of the TD-UTD slope diffraction coefficients indicate slightly different levels of accuracy, and both are valid when the incident wave is rapidly varying spatially in a direction perpendicular to the incident ray at the edge. Other slope diffracted fields [11,12] are not considered in this work. In Section 3, numerical results based on the two different versions of the TD-UTD slope diffracted fields are presented and compared with an exact TD solution for the special case of a straight wedge given previously by Felsen [13].…”

Section: Introductionmentioning

confidence: 99%

Time-domain uniform geometrical theory of diffraction for a curved wedge

Rousseau¹,

Pathak²

1995

IEEE Trans. Antennas Propagat.

149

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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].

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GTD solution with higher order terms to the diffraction by an edge: towards a uniform solution

Cited by 10 publications

References 3 publications

Inhomogeneous electromagnetic plane wave diffraction by a perfectly electric conducting wedge at oblique incidence

Inhomogeneous electromagnetic plane wave diffraction by a perfectly electric conducting wedge at oblique incidence

Last PhD supervised by Professor Kouyoumjian: Extended UTD by Dr. Buyukdura

Time-domain uniform geometrical theory of diffraction for a curved wedge

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