Uniform Asymptotic Physical Optics Solutions for a Set of Diffraction Problems

Riccio, Giovanni

doi:10.5772/6844

Cited by 6 publications

(7 citation statements)

References 17 publications

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“…According to [2], the next step is the use of the unit vector of the diffraction directionŝ = cos φx + sin φŷ instead ofR in Eq. (7):…”

Section: Free-space Region ωmentioning

confidence: 99%

“…The integral in Eq. (12) is reduced to a typical diffraction integral that is evaluated by means of the Steepest Descent Method and the Multiplicative Method in the high-frequency approximation [2].…”

Section: Free-space Region ωmentioning

confidence: 99%

“…The frequency domain Uniform Asymptotic Physical Optics (FD-UAPO) approach has recently emerged as a useful and alternative high-frequency method to obtain closed form approximate solutions to plane wave diffraction problems [2]. No special functions and integral equations must be computed by means of numerical techniques since such solutions contain the UTD transition function and the Geometrical Optics (GO) response of the structure in terms of reflection and transmission coefficients.…”

Section: Introductionmentioning

confidence: 99%

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Diffraction by a Dielectric Wedge on a Ground Plane

Frongillo¹,

Gennarelli²,

Riccio³

2019

PIER M

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The plane wave diffraction by an acute-angled wedge located on a perfect electric conducting plane is studied in the frequency and time domains. Only a TMz polarization is explicitly considered in the manuscript since the case of a TEz polarization can be solved in a similar way. At first, the uniform asymptotic physical optics approach is used to obtain the diffraction coefficients in the framework of the uniform geometrical theory of diffraction. The analytical procedure allows one to obtain closed form expressions that are easy to handle and provide reliable results from the engineering viewpoint. The time domain diffraction coefficients are successively determined by applying the inverse Laplace transform to the frequency domain counterparts. The effectiveness of the proposed solutions is proved by means of numerical tests and comparisons with full-wave numerical techniques.

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“…According to [2], the next step is the use of the unit vector of the diffraction directionŝ = cos φx + sin φŷ instead ofR in Eq. (7):…”

Section: Free-space Region ωmentioning

confidence: 99%

Section: Free-space Region ωmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Diffraction by a Dielectric Wedge on a Ground Plane

Frongillo¹,

Gennarelli²,

Riccio³

2019

PIER M

Self Cite

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“…Therefore, it results in modification in the surrounding space. The ability of solving and describing the scattering problem is the essence to many applications, such as designing antenna to identify radar targets and planning radio links [102]. Also, for the purpose of this thesis, where we need to analyse the scattering by dielectric ice crystals, the electromagnetic scattering and diffraction modeling is needed.…”

Section: Geometrical and Uniform Theories Of Diffractionmentioning

confidence: 99%

Modelling of Electromagnetic Scattering at Infrared Wavelengths by Pristine Ice Crystals

Shaker¹,

Bebbington²

2019

Journal of Nanoelectronics and Optoelectronics

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Cirrus clouds substantially impact Earth's atmospheric system, including its radiative budget, both of which enormously influence all scales of weather regions and processes. The shapes of ice crystals are ultimately determined by incident coordinate systems and relevant geometric models, specifically computational geometry and applied mathematics. and incident coordinate systems determine the shapes of ice crystals (Takano, Y. and Liou, K.N., 1995. Radiative transfer in cirrus clouds. Part III: Light scattering by irregular ice crystals. Journal of the Atmospheric Sciences, 52 (7), pp.818–837.). However, the scattering solution present in the infrared's spectrum area a complex dilemma. In previous attempts to solve scattering methods, such as Rayleigh theories, Mie and T-matrix methods, various established methods have been explored. However, it is important to note that such methods are faulty at infrared wavelengths because of size parameters, which can often exceed 100, consequently resulting in intensive computation. This paper presents a new approach based on physical optics and attempts to evaluate scattering by smooth prismatic dielectric ice crystals—specifically those which are electrically large. This method suggests that the total scattered amplitude in any trend can be measured by applying the reaction theorem to a volume interval from understanding internal field distribution. Subsequently, it is possible to convert this integral to an integral over an equivalent surface current distribution, thus, enabling total surface field analysis. The scattered field solution of the proposed physical optics method has been compared with ray-launching geometrical optics. Overall, the recommend method shows a good agreement when the scatterer is considered sizably large in comparison to wavelength. The proposed method exhibits good potential to be applied for ice crystals with rough surface structure.

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“…The Uniform Asymptotic Physical Optics (UAPO) approach has recently emerged as a useful, reliable, and alternative high-frequency analytical method to obtain approximate uniform solutions to plane wave diffraction problems involving penetrable and impenetrable structures [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The UAPO solutions can be used in the framework of the Uniform Geometrical Theory of Diffraction (UTD) [20] and are expressed in a closed form containing only standard functions and parameters as the trigonometric functions, the UTD transition function, and the geometrical optics (GO) response of the structure in terms of reflection and transmission coefficients.…”

Section: Introductionmentioning

confidence: 99%

High-frequency diffraction contribution by planar metallic–DNG metamaterial junctions

Gennarelli

Riccio

2020

Int. J. Microw. Wireless Technol.

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The plane wave diffraction by a planar junction consisting of a thick metallic sheet and a lossy double-negative metamaterial slab is studied by using the Uniform Asymptotic Physical Optics approach. This approach assumes the radiation integral as a starting point and uses the physical optics surface currents as sources to be integrated. The integral is manipulated by taking advantage of useful approximations and evaluations, and re-formulated in order to apply an asymptotic procedure able to generate a closed-form approximate solution in the framework of the Uniform Geometrical Theory of Diffraction. Accordingly, advantages and drawbacks result from the application of the proposed solution. The jumps of the geometrical optics field are compensated. Implementation and handling of the computer code are facilitated by the evaluation of well-known functions and parameters. No differential/integral equations or special functions must be computed.

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Uniform Asymptotic Physical Optics Solutions for a Set of Diffraction Problems

Cited by 6 publications

References 17 publications

Diffraction by a Dielectric Wedge on a Ground Plane

Diffraction by a Dielectric Wedge on a Ground Plane

Modelling of Electromagnetic Scattering at Infrared Wavelengths by Pristine Ice Crystals

High-frequency diffraction contribution by planar metallic–DNG metamaterial junctions

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