WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653
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Article Wave Diffraction by Material Half-Planes(Elsevier Gmbh, Urban & Fischer verlag, 2017) Umul, Yusuf ZiyaThe diffraction of E-polarized electromagnetic waves by resistive and conductive half planes is studied. The solution of Maliuzhinets for the scattering problem of plane waves from an impedance half-screen is taken into account. The diffracted fields from the resistive and conductive half-planes are obtained by using a relation between the scattered waves from material surfaces. The integrals ofscattering are also constructed in the complex plane. The resultant field expressions are compared with the literature numerically. (C) 2016 Elsevier GmbH. All rights reserved.Article Citation - WoS: 2Citation - Scopus: 2Diffraction by Material Half-Planes for Grazing Incidence(Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf ZiyaIt is shown that the actual solutions of the diffraction problem of waves by material half planes do not reduce to the correct diffracted field expressions for grazing incidence. The correct expressions are obtained for the diffracted waves by resistive and conductive half screens. The case for the impedance half-plane directly emerges in terms of the diffracted fields by the previous two semi-screens. The behaviors of the geometric optics and diffraction waves are investigated numerically. (C) 2017 Elsevier GmbH. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 5Wave Diffraction by a Soft/Hard Strip: Modified Theory of Physical Optics Solution(Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf ZiyaThe scattering problem of waves by a strip, the faces of which are composed of soft and hard surfaces, is investigated by the method of modified theory of physical optics. The scattering integral is divided into two parts according to the single effects of the faces. The boundary conditions are integrated into the integrals and the resultant field expressions are obtained by the asymptotic evaluation methods. The scattered waves are examined numerically. (C) 2017 Elsevier GmbH. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1Physical Optics Based Simple Expressions for Diffracted Waves by Transmissive Half-Planes(Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf ZiyaThe diffracted fields by resistive and conductive half-screens, which transmit a portion of the incident wave and reflect the remaining part, are expressed in terms of simple expressions that are based on the diffraction coefficient of an impedance half-plane. Also alternative representations are derived for the diffracted fields and their effects are studied for different values of surface parameters. The results are examined numerically. (C) 2018 Elsevier GmbH. All rights reserved.Article Citation - WoS: 1A Uniform Function for the Diffraction of Spherical Waves(Elsevier Gmbh, Urban & Fischer verlag, 2017) Umul, Yusuf ZiyaA function which occurs in the scattering problem of the spherical waves by a perfectly conducting half-plane is introduced for constructing the transition functions of the uniform theory of diffraction and uniform asymptotic theory of diffraction. The important properties of the function, related with the geometrical optics and diffracted field components, are derived mathematically. A uniform asymptotic theory of wedge diffraction is introduced based on the new function. The resultant field expressions-are investigated numerically. (C) 2016 Elsevier GmbH. All rights reserved.Article Wave Diffraction by a Metallic Half-Plane(Elsevier Gmbh, Urban & Fischer verlag, 2016) Umul, Yusuf ZiyaThe scattering problem of plane waves by a half-screen with different face impedance is obtained with a geometrical optics-physical optics based method. The kernel of the physical optics integral is redefined by using coefficients that guarantee the satisfaction of the boundary condition on the surface of the scatterer. The uniform diffraction fields are obtained and the behavior of the scattered waves is investigated numerically for different values of the surface impedance. (C) 2015 Elsevier GmbH. All rights reserved.Article Scattering of Waves by an Aperture in an Impedance Screen(Elsevier Gmbh, Urban & Fischer verlag, 2012) Umul, Yusuf ZiyaThe transmission and diffraction of waves by an aperture in an impedance screen is investigated. The Senior's solution of the scattering problem of waves by an impedance half-plane is transformed into a physical optics type integral. The obtained method is applied to the transmission problem of waves by a slit in an impedance screen. The results are compared with the aperture problem in black and conducting screens numerically. (C) 2012 Elsevier GmbH. All rights reserved.