WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653
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Article Citation - WoS: 8Citation - Scopus: 9Diffraction of Waves by an Impedance Half-Plane(Elsevier Science Bv, 2013) Umul, Y. Z.The solution of the diffraction problem of waves by an impedance half-plane that satisfies the impedance boundary condition is obtained for the first time in the literature. A reflection coefficient which is the function of the angular and spatial variables in the polar coordinates is defined and its exact expression is obtained with the aid of the impedance boundary condition. The resultant diffraction field is compared with the solution of Malyuzhinets numerically and their differences are stressed. The structures of the total scattered, geometrical optics and diffracted waves are also investigated. (C) 2013 Elsevier B.V. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 2Physical Optics Approach To Wave Diffraction by a Perfect Electromagnetic Conductor Half-Plane(Springer, 2021) Umul, Yusuf ZiyaThe scattering of electromagnetic plane waves by a perfect electromagnetic conductor is investigated. The method of physical optics is used for the analysis of the problem. The reflected fields by a whole-plane are taken into account. The surface electric and magnetic current densities are constructed with the aid of the incident wave and the reflected field from the whole-surface. The scattering integrals are obtained for the electric and magnetic vector potentials. The scattered electric and magnetic fields are expressed in terms of the vector potentials. The scattering integrals are evaluated asymptotically for large values of the wave-number. Some numerical results are given.Article Citation - WoS: 22Citation - Scopus: 20The Method of Transition Boundary for the Solution of Diffraction Problems(Springer, 2019) Umul, Yusuf ZiyaA new method, which enables one to solve some diffraction problems, is put forth. The technique is based on a relation between the diffracted and scattered geometric optics waves at the transition boundaries. The concept of initial waves is also used instead of the incident field. The general algorithm of the method is outlined and applied to the diffraction problems of waves by perfect electric conductor half-screen, resistive half-plane and impedance sheet junction.Article Citation - WoS: 6Citation - Scopus: 8Diffraction of Waves by a Perfect Electromagnetic Conductor Half-Plane Between Isorefractive Media(Springer, 2019) Basdemir, Husnu DenizIn this study, diffraction of waves by a perfectly electromagnetic conductor half-plane which is lying at the boundary of isorefractive media is investigated. The diffracted field expressions are constructed by using the relation between scattered geometrical optics fields and the transition boundaries. The high frequency asymptotic expressions of diffracted fields reach infinite magnitude values at the transition boundaries. The uniform expressions of fields are obtained by using the uniform theory of diffraction method in order to obtain the finite magnitude values at the transition boundaries and the results are analyzed numerically for different set of parameters.Article Citation - WoS: 4Citation - Scopus: 5Interaction of Plane Waves by a Half-Screen Between Two Different Media(Springer, 2018) Umul, Yusuf ZiyaThe diffraction process of plane waves by a perfectly electric conducting half-screen, residing at a planar junction between two different media, is investigated. The scattered geometrical optics waves are evaluated by subtracting the initial fields from the total geometrical optics waves. The diffracted waves are obtained from the scattered geometrical optics fields by using a relation at the transition boundaries. The diffracted waves are expressed separately for both of the media. The uniform representations of the diffracted fields are obtained by using the uniform theory of diffraction. The scattered fields are analyzed numerically.Article Citation - WoS: 3Citation - Scopus: 4Edge Diffraction in an Anomalously Reflecting Half-Plane(Springer, 2018) Umul, Yusuf ZiyaA half-plane, formed of anomalously reflecting metasurface, is taken into account. The layer is modeled by an impedance half-screen. In order to obtain the diffracted fields, the geometrical optics waves are evaluated as a sum of equivalent soft, hard and impedance surfaces. The diffracted waves are derived by the superposition of the diffracted fields from the equivalent surfaces. The uniform field expressions are obtained by the method of uniform theory of diffraction. The behaviors of the fields are studied numerically.Article Citation - WoS: 15Citation - Scopus: 13Diffraction of Line Source Field by a Resistive Half-Plane Between Isorefractive Media(Springer, 2017) Umul, Yusuf ZiyaThe scattering process of cylindrical waves by a resistive half-plane, residing at the interface of isorefractive media, is investigated. The uniform expression of the diffracted cylindrical waves by a resistive half-screen is obtained for a single medium. Then the initial fields are found for an interface between isorefractive media. The scattered geometrical optics waves are derived by subtracting the initial fields from the total geometrical optics waves when the resistive half-plane exists at the interface. The diffracted fields are determined by using the scattered geometrical optics waves. The behavior of the resultant waves is analyzed numerically.Article Citation - WoS: 1Citation - Scopus: 1Scattering of Waves by a Half-Screen With Different Face Impedances: Closed Form Series Solution(Taylor & Francis Ltd, 2013) Umul, Yusuf Z.A novel series solution is obtained for the scattering problem of waves by a half-plane with different face impedances. The impedance condition is expressed in terms of the sum of Dirichlet and Neumann conditions, multiplied by appropriate coefficients. The scattering problem of plane waves by an interface between two half-planes with different impedances is also investigated. The results are compared with the literature, numerically.Article Citation - WoS: 7Citation - Scopus: 7Diffraction of Waves by a Perfectly Conducting Half-Plane Between Two Dielectric Media(Elsevier, 2014) Umul, Yusuf ZiyaThe scattered fields by a perfectly conducting half-plane, located at the interface of two dielectric media, are investigated. The diffracted fields are defined with novel reflection and transmission coefficients that are functions of the observation distance and angle. These coefficients reduce to the constant reflection and transmission coefficients of the geometrical optics wave. The unknown quantities in the coefficients of the diffracted waves are determined according to the boundary conditions on the half-plane and the interface of the dielectric media. The resultant field expressions are investigated numerically and the behavior of the scattered and diffracted waves are studied. (C) 2013 Elsevier B.V. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 4Transmission of a Bessel Beam Through a Circular Aperture in an Impedance Screen(Iop Publishing Ltd, 2014) Umul, Yusuf ZiyaThe scattering effect of a circular aperture, located in an impedance plane, on a Bessel beam is investigated by decomposing the scattered wave into two subcomponents, namely the geometrical optics and diffracted fields. The diffracted waves are investigated with the aid of the geometrical theory of diffraction. The detour parameter is evaluated and the existence zones of the geometrical optics fields are determined. The various aspects of the reflected and transmitted scattered waves, including the self healing of the beam, are studied numerically.