Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
Browse
9 results
Search Results
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: 7Citation - Scopus: 9Rubinowicz Transform of the Mtpo Surface Integrals(Elsevier Science Bv, 2008) Umul, Yusuf Z.The surface integral of the modified theory of physical optics is reduced to a line integral by using the Rubinowicz transform for the incident scattered fields by an arbitrary aperture in a black surface. The integral theorem of Kirchhoff is applied to the scattering geometry and the diffracted fields are expressed in terms of a line integral along the contour of the diffracting edge. (C) 2008 Elsevier B.V. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1Interaction of Electromagnetic Waves With a Resistive Half-Plane(Springer France, 2016) Umul, Yusuf Z.The interaction process of electromagnetic waves by a resistive half-plane is investigated. The scattered geometrical optics fields are obtained by subtracting the incident field from the total geometrical optics waves. The physical optics integral of the scattered waves is derived with the aid of the scattered geometrical optics fields. The edge diffracted waves are derived from the physical optics integral by the edge point technique. A correction field is added to the diffracted fields in order to obtain a solution that satisfies the resistive boundary conditions on the surface of the half-screen. The uniform diffracted fields are expressed in terms of the Fresnel function and the resultant field representations are compared with the literature numerically.Article Citation - WoS: 3Citation - Scopus: 3A Hybrid Maliuzhinets/Po Method for Diffraction Problems by Impedance Wedges(Elsevier Science Bv, 2011) Umul, Yusuf ZiyaThe solution of Maliuzhinets of the diffraction problem of waves by an impedance wedge is transformed into a physical optics integral. The resultant expression is suitable for the investigation of various diffraction problems having impedance wedges. The method is applied to the scattering of waves by an impedance spherical reflector with wedge structure at its discontinuity. The results are examined numerically. (C) 2011 Elsevier B.V. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1Boundary Diffraction Wave Theory of Resistive Surfaces With Edge Discontinuities(Elsevier, 2011) Umul, Yusuf ZiyaThe line integral of the boundary diffraction wave theory is derived by considering the exact diffracted fields of a resistive half-plane. The line integral is generalized for arbitrary resistive surface with edge discontinuity. The method is applied to the diffraction problem of waves by a convex resistive spherical reflector and the resultant field expressions are investigated numerically. (C) 2011 Elsevier B.V. All rights reserved.Article Citation - WoS: 10Citation - Scopus: 13Physical Optics Theory for the Scattering of Waves by an Impedance Strip(Elsevier Science Bv, 2011) Umul, Yusuf ZiyaThe physical optics integral of the scattered waves by an impedance strip is derived by using the modified theory of physical optics. The surface currents of the physical optics integral, which was introduced for the scattered waves by an impedance half-plane, are taken into account. The uniform diffracted fields of the impedance strip are evaluated asymptotically. The second order diffraction terms are also obtained. The total scattered field and its subcomponents are plotted and the effect of the second order diffraction and strip width to the scattering is investigated numerically. (C) 2010 Elsevier B.V. All rights reserved.Article The Physical Optics of Phase-Conjugate Mirrors: Scalar Theory(Elsevier, 2011) Umul, Yusuf ZiyaA scalar theory of physical optics is developed for the scattered waves by finite or infinite phase-conjugate mirrors. The method is applied to the scattering problem of waves by a semi-infinite phase-conjugate mirror. The results are examined numerically and compared with the scattered waves by a conducting half-plane. The effect of the phase-conjugation to the location of the transition region is outlined. (C) 2011 Elsevier B.V. All rights reserved.Article Citation - WoS: 12Citation - Scopus: 13The Relation Between the Boundary Diffraction Wave Theory and Physical Optics(Elsevier Science Bv, 2008) Umul, Yusuf Z.The physical optics surface integral is asymptotically reduced to a line integral along the contour of the diffracting edge. It is shown that the resultant integral can be separated into two sub-integrals which represent the reflected and transmitted diffracted fields. The integrands are transformed into the same forms with the potential function of the boundary diffraction wave theory. (C) 2008 Elsevier B.V. All rights reserved.Article Citation - WoS: 13Citation - Scopus: 13The Effect of Impedance Boundary Conditions on the Potential Function of the Boundary Diffraction Wave Theory(Elsevier, 2008) Yalcin, U.; Umul, Y. Z.A novel potential function of the boundary diffraction wave theory is obtained for the impedance surfaces by the asymptotic reduction of the modified theory of physical integrals. The function is expressed in terms of the direction vectors of the incident and scattered rays. The application of the method is performed on the problem of diffraction of plane waves by an impedance half plane for oblique incidence. (c) 2007 Elsevier B.V. All rights reserved.