Browsing by Author "Umul, Y.Z."

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Diffraction of Matter Waves in Time by an Absorbing Half-Screen
(2010) Umul, Y.Z.; Umul, Yusuf Ziya; 42699; Elektronik ve Haberleşme Mühendisliği; 06.02. Elektronik ve Haberleşme Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
In this study, the scattering of matter waves that accompany to the quantum particles by an absorbing half-plane is examined. A quantum shutter, which is opened at an initial time, is proposed to close the semi-infinite complementary aperture of the half-screen. Hence the matter waves, confined in a determined region of space, transmits to the second region by scattering from the semi-infinite aperture. The mathematical expressions of the scattered fields are plotted numerically and interpreted according to the diffraction theory of Young.
Citation - Scopus: 18
Diffraction Theory of Waves by Resistive Surfaces
(Electromagnetics Academy, 2010) Yalçin, U.; Umul, Y.Z.; 01. Çankaya Üniversitesi; 06.02. Elektronik ve Haberleşme Mühendisliği; 06. Mühendislik Fakültesi
Diffraction of scalar plane waves by resistive surfaces are investigated by defining a new boundary condition in terms of the Dirichlet and Neumann conditions. The scattering problems of waves by a resistive half-plane and the interface between resistive and perfectly magnetic conducting half-planes are examined with the developed method. The resulting fields are plotted numerically. The numerical results show that the evaluated field expressions are in harmony with the theory.
Citation - Scopus: 19
Improved Equivalent Source Theory
(OSA - The Optical Society, 2009) Umul, Y.Z.; 01. Çankaya Üniversitesi; 06.02. Elektronik ve Haberleşme Mühendisliği; 06. Mühendislik Fakültesi
The equivalent source theorem, which is an important technique in the study of radiation and scattering by apertures, is improved by using the two axioms of the modified theory of physical optics. The method is applied to the problem of radiation of electromagnetic waves by a parallel plate waveguide. The results are investigated numerically. © 2009 Optical Society of America.
Citation - Scopus: 11
Rigorous Expressions for the Equivalent Edge Currents
(Electromagnetics Academy, 2009) Umul, Y.Z.; 01. Çankaya Üniversitesi; 06.02. Elektronik ve Haberleşme Mühendisliği; 06. Mühendislik Fakültesi
An exact form for the equivalent edge current is derived by using the axioms of the modified theory of physical optics and the canonical problem of half-plane. The edge current is expressed in terms of the parameters of incident and scattered rays. The analogy of the method with the boundary diffraction wave theory is put forward. The edge and corner diffracted waves are derived for the problem of a black half-strip.