WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653

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Author: search.filters.author.Umul, Yusuf ZiyaPublisher: search.filters.publisher.Elsevier Gmbh, Urban & Fischer verlag

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Now showing 1 - 10 of 23
  • Article
    Citation - WoS: 1
    Citation - Scopus: 2
    General Expression of the Diffracted Waves by a Half-Screen With Generalized Impedance Boundary Conditions
    (Elsevier Gmbh, Urban & Fischer verlag, 2019) Umul, Yusuf Ziya
    The diffraction process of plane waves by a half-screen with generalized impedance boundary conditions is studied. Firstly, the scattered geometrical optics waves are obtained by subtracting the incident field from the total geometrical optics wave. The diffracted field expressions are derived by taking into account the construction of the scattered geometrical optics wave for first, second and third order impedance half-planes. Then the diffracted field expression is generalized for the Nth order half-screen. The uniform representation of the edge diffracted wave is obtained by considering the exact solution of Sommerfeld. The behaviors of the total, total GO and diffracted fields are analyzed numerically.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Wave Diffraction by a Half-Screen With Nth Order Generalized Sheet Transition Conditions
    (Elsevier Gmbh, Urban & Fischer verlag, 2019) Umul, Yusuf Ziya
    The scattering of plane waves by a half-plane with Nth order transition conditions is investigated. First of all, the reflection and transmission conditions of the transmissive surface are evaluated by using the generalized sheet transmission boundary conditions. The scattered geometrical optics fields are determined from the total geometrical optics and incident waves. The diffracted field is obtained by using a relation between the scattered geometrical optics and diffracted waves. The behaviors of the total, total geometric optics and diffracted fields are analyzed numerically.
  • Article
    Wave Diffraction by Material Half-Planes
    (Elsevier Gmbh, Urban & Fischer verlag, 2017) Umul, Yusuf Ziya
    The 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: 10
    Citation - Scopus: 11
    Wave Diffraction by the Junction Between Resistive and Soft-Hard Half-Screens
    (Elsevier Gmbh, Urban & Fischer verlag, 2017) Umul, Yusuf Ziya
    The scattering process of planes waves by a junction between resistive and soft/hard half-planes is investigated. First of all, the initial and total geometrical optics fields are determined by considering the related geometries. The scattered geometrical optics wave is obtained by subtracting the initial field from the total geometrical optics wave. The diffracted fields are derived by taking into account the behaviour of the geometrical optics wave at the reflection and shadow boundaries. The uniform expressions of the diffracted waves are constructed with the aid of the uniform theory of diffraction. The total field expressions are examined numerically. (C) 2016 Elsevier GmbH. All rights reserved.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Exact Form of the Physical Optics Integral
    (Elsevier Gmbh, Urban & Fischer verlag, 2017) Umul, Yusuf Ziya
    The exact structure of the physical optics integral is obtained. With this aim, the rigorous solution of the diffraction problem of waves by a perfectly conducting half-plane is considered. The Fresnel integrals of the incident and reflected scattered fields are transformed into the physical optics integrals by defining a suitable variable transform. The relation of the obtained integral with the modified theory of physical optics is discussed. (C) 2016 Elsevier GmbH. All rights reserved.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Diffraction of Electromagnetic Waves by a Wedge With Perfectly Absorbing and Impedance Faces
    (Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf Ziya
    The scattering process of electromagnetic waves by a wedge with perfectly absorbing and impedance faces is investigated. The scattered geometric optics waves are obtained for two cases, namely the illumination of single and double faces. The geometric optic field is expressed as a sum of two fields, which represent two wedges with different boundary conditions. The diffracted waves are determined for both of the wedge configurations. The behaviours of the total, total geometric optics and diffracted fields are studied numerically.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 8
    Kinetic Energy Based Relativistic Wave Equation
    (Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf Ziya
    The Schrodinger equation is based on a Hamiltonian, which is the sum of kinetic and potential energies. The energy term, in the relativistic energy-momentum relation, is divided into its kinetic and rest energy components according to the Hamiltonian of the Schrodinger equation. The differential equation is obtained by using the plane wave representation. It is found that the derived form of the Klein-Gordon equation is more similar to the Schrodinger equation than the classical one. Non-relativistic limit is also studied.
  • Article
    Citation - WoS: 1
    Radiation of Electromagnetic Waves by a Time-Harmonic Surface Charge Density
    (Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf Ziya; Yusuf, Ziya Umul
    The radiation process of waves by a time harmonic electric charge density, located on the surface of a conducting sphere, is investigated. The current density is evaluated using the continuity equation. The scalar and vector potential are obtained by using the integral solution of the inhomogeneous Helmholtz equation. The radiated electric and magnetic fields are derived. The effect of the ground is put forth. The behaviors of the waves are studied numerically. (C) 2018 Elsevier GmbH. All rights reserved.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 8
    Diffraction of Waves by a Planar Junction Between Perfectly Absorbing and Resistive Sheets
    (Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf Ziya
    The scattering of plane waves by a planar junction between perfectly absorbing and resistive half-planes is studied. The scattered geometrical optics fields are evaluated from the difference of the total geometrical optics and initial fields. The diffracted waves by the junction are obtained with the aid of a relation between the scattered geometrical optics and diffracted fields. The uniform expressions of the diffraction fields are derived by using the uniform theory of diffraction. The behaviors of the total field and its components are analyzed numerically. (C) 2018 Elsevier GmbH. All rights reserved.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Diffraction by Material Half-Planes for Grazing Incidence
    (Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf Ziya
    It 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.