Elektronik ve Haberleşme Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/260
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Article Citation - WoS: 4Citation - Scopus: 5Diffraction of Electromagnetic Waves by a Planar Interface Between Perfectly Absorbing and Anomalously Transmitting Metasurface Half-Planes(Elsevier Gmbh, 2019) Umul, Yusuf ZiyaThe interaction process of electromagnetic waves by a planar interface between perfectly absorbing and anomalously refracting metasurface half-planes is investigated. First of all, the scattered geometric optics field is obtained from the difference of the total geometric optics and initial waves. The diffracted fields are determined by using a relation between the scattered geometric optics and diffraction waves at the transition boundaries. It consists of the diffraction fields of perfectly absorbing and anomalously refracting metasurface half-screens. The behaviors of the total, total geometric optics and diffracted waves are studied numerically.Article Citation - WoS: 1Citation - Scopus: 1Interaction of Electromagnetic Waves by a Cylindrical Parabolic Mesh Reflector(Elsevier Gmbh, 2019) Umul, Yusuf ZiyaA cylindrical parabolic reflector, composed of mesh grid, is modeled by a resistive surface. The analysis of the scattered waves is performed by the physical optics integral, which was developed for resistive surfaces. The integral is evaluated asymptotically for large values of the wave-number in high-frequencies. The geometrical optics and diffracted fields are obtained by the methods of stationary phase and edge point respectively. The uniform forms of the diffracted waves are derived. The total wave and its components are investigated numerically for different values of surface resistivity.Article Citation - WoS: 4Citation - Scopus: 4An Analytical Solution for the Plane Wave Diffraction by a Resistive Half-Plane Residing at the Interface of Left and Right Handed Media(Elsevier Gmbh, 2019) Basdemir, Husnu DenizThe diffraction of waves by a resistive half-plane lying on the interface of left and right handed media is investigated in this study. Because of the anomalous refraction property of left handed media, shadow boundary shifts toward to the lower surface of the half-plane. In order to obtain the shifted boundary, diffracted waves are divided to subfields. Thus, obtained diffracted waves compensates the deficiency of geometries optics fields at the transition regions. The uniform version of waves is obtained by using the uniform theory of diffraction. The wave behaviors are examined numerically.Article Citation - WoS: 1Citation - Scopus: 1Wedge Diffraction Model in Gravitational Lensing by Cosmic Strings(Elsevier Gmbh, 2018) Umul, Yusuf ZiyaA cosmic string forms a conical topology, which enables a diffraction phenomenon by a wedge with an inner angle, equals to the double of the deficit angle. A wedge, on the edge of which the string is located, is defined in the flat space-time. The radiated wave from a star is represented by two plane waves, propagating on the two surfaces of the wedge for grazing incidence. The uniform expressions of the diffracted waves are obtained and investigated numerically. (C) 2017 Elsevier GmbH. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1The Relation Between Wave Vector and Momentum in Quantum Mechanics(Elsevier Gmbh, 2016) Umul, Yusuf Z.The fundamental relation of quantum mechanics, which correlates the momentum of a quantum particle to the wave vector of the matter wave, is re-interpreted. The wave vector, in the relation, is formulized as the integration of it along the angular coordinates for two and three dimensional cases. Various evaluations of the wave vector are performed for different types of waves and the results are discussed. Also the edge diffracted fields are considered according to the new interpretation. (C) 2016 Elsevier GmbH. All rights reserved.Article Citation - WoS: 3Citation - Scopus: 4Impedance Surface Diffraction Analysis for a Strip With the Boundary Diffraction Wave Theory(Elsevier Gmbh, 2013) Basdemir, H. DenizThe content of the present paper is mainly about the application of the boundary diffraction wave theory to an impedance strip. This method reduces the diffraction surface integrals to line integrals. Hence, line integral directly gives the diffraction integral. Evaluation of diffraction integral gives only the diffracted fields. The vector potential which is used for the construction of the line integral is reduced to the modified theory of physical optics (MTPO) integral. With the assistance of this method diffracted fields are directly obtained and investigated numerically. (c) 2012 Elsevier GmbH. All rights reserved.