Elektronik ve Haberleşme Mühendisliği Bölümü

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Citation - WoS: 4
Citation - Scopus: 4
An 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 Deniz
The 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.
Citation - WoS: 6
Citation - Scopus: 8
Babinet's Principle in the Fraunhofer Diffraction by a Finite Thin Wire
(Elsevier Gmbh, Urban & Fischer verlag, 2011) Umul, Yusuf Ziya
The scattered waves by a thin finite wire are evaluated by using the Rayleigh-Sommerfeld integral in the Fraunhofer approximation. The scattered fields by the complementary thin wire are also obtained with the aid of the Babinet's principle. The scattering integrals are evaluated directly. It is shown that Babinet's principle holds excellently for this problem. The scattered fields are examined numerically. (C) 2010 Elsevier GmbH. All rights reserved.
Babinet's principle in the Fraunhofer diffraction by a finite thin wire
(Elsevier GMBH, 2011) Umul, Yusuf Ziya
The scattered waves by a thin finite wire are evaluated by using the Rayleigh-Sommerfeld integral in the Fraunhofer approximation. The scattered fields by the complementary thin wire are also obtained with the aid of the Babinet's principle. The scattering integrals are evaluated directly. It is shown that Babinet's principle holds excellently for this problem. The scattered fields are examined numerically
Citation - WoS: 14
Citation - Scopus: 15
Closed Form Series Solution of the Diffraction Problem of Plane Waves by an Impedance Half-Plane
(Iop Publishing Ltd, 2009) Umul, Yusuf Z.
The scattering problem of plane waves by an impedance half-plane is solved by using the method of separation of variables, and a closed form series expression, which separately reduces to the cases of soft and hard half-planes, is obtained. The results are investigated numerically and compared with the solutions in the literature.
Citation - WoS: 4
Citation - Scopus: 5
Diffraction of Electromagnetic Waves by a Planar Interface Between Perfectly Absorbing and Anomalously Transmitting Metasurface Half-Planes
(Elsevier Gmbh, 2019) Umul, Yusuf Ziya
The 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.
Citation - WoS: 3
Citation - Scopus: 4
Diffraction of Plane Waves by a Black Wedge
(Elsevier Sci Ltd, 2010) Umul, Yusuf Z.
The scattering of plane waves by a black wedge is examined. Two methods are considered for the solution of the problem. A closed-form series solution is derived by performing the technique of the separation of variables using boundary conditions of Macdonald. The second approach is the method of the modified theory of physical optics. The results are compared numerically. (C) 2009 Elsevier Ltd. All rights reserved.
Citation - Scopus: 1
Diffraction of Waves by a Conductive Half-Plane
(Elsevier Gmbh, Urban & Fischer verlag, 2017) Umul, Yusuf Ziya
The scattering process of plane waves by a conductive half-plane is investigated. The scattered geometrical optics waves are obtained by subtracting the incident field from the total geometrical optics waves. The physical optics integral is constructed from the scattered geometrical optics fields. The diffracted waves are evaluated by the application of the edge point method to the physical optics integral. A correction field is added to the diffracted waves in order to satisfy the conductive boundary conditions on the surfaces of the half plane. The uniform diffracted fields are evaluated and the resultant scattered waves are compared with the literature numerically. (C) 2016 Elsevier GmbH. All rights reserved.
Citation - WoS: 13
Citation - Scopus: 13
The 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.
Citation - WoS: 3
Citation - Scopus: 4
Impedance Surface Diffraction Analysis for a Strip With the Boundary Diffraction Wave Theory
(Elsevier Gmbh, 2013) Basdemir, H. Deniz
The 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.
Citation - WoS: 1
Citation - Scopus: 1
Interaction of Electromagnetic Waves by a Cylindrical Parabolic Mesh Reflector
(Elsevier Gmbh, 2019) Umul, Yusuf Ziya
A 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.
Citation - WoS: 33
Citation - Scopus: 36
Mtpo Based Potential Function of the Boundary Diffraction Wave Theory
(Elsevier Sci Ltd, 2008) Umul, Yusuf Z.
A novel potential function is introduced by using the modified theory of physical optics integrals for a perfectly conducting half-plane. The function is valid for arbitrary aspects of observation. The line integration of these functions gives the total scattered fields. The method is applied to the problem of diffraction of plane waves by an opaque half-plane for oblique incidence. (c) 2008 Elsevier Ltd. All rights reserved.
Citation - WoS: 3
Citation - Scopus: 4
Po and Ptd Approach To the Diffraction Problem by a Resistive Half-Plane
(Taylor & Francis Ltd, 2014) Basdemir, Husnu Deniz
Diffracted fields from a resistive half-plane were investigated by the method of physical optics (PO) and the physical theory of diffraction. The coefficient of the PO scattering integral was derived for the first time for the resistive half-plane. Uniform fringe field expressions were obtained in terms of the Fresnel functions. The resultant expressions of the fringe fields were plotted and analyzed numerically.
Citation - WoS: 1
Citation - Scopus: 1
The 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.
Review On The Modified Theory of Physical Optics
(IEEE, 2018) Başdemir, Hüsnü Deniz
In this review, modified theory of physical optics approach to the diffraction problem is revisited. The important aspects of the method are explained and steps for the usage of the method are revealed. Also, historical progress of the method is mentioned.
Citation - WoS: 3
Citation - Scopus: 3
Scattering of Inhomogeneous Plane Waves by a Truncated Cylindrical Cap
(Taylor & Francis Ltd, 2015) Basdemir, Husnu Deniz
Scattered fields of the inhomogeneous plane waves from a truncated cylindrical cap are obtained. Also the uniform diffracted fields are performed in terms of the Fresnel functions. Reflected and diffracted fields are obtained by using the physical optics and the geometrical theory of diffraction methods, respectively. All the mentioned results are plotted numerically for various numerical parameters.
Scattering of plane waves by a half-plane at the interface of two ısorefractive media
(2015) Başdemir, Hüsnü Deniz
Scattering of plane waves by a half-plane at the boundary of two isorefractive media is analyzed. The E-polarization case is taking into account. The results were analyzed numerically and compared with a similar previous study. The results are consistent with each other.
Citation - WoS: 12
Citation - Scopus: 12
Scattering of Waves by a Perfectly Conducting Wedge Residing at the Interface Between Two Isorefractive Media
(Ieee-inst Electrical Electronics Engineers inc, 2016) Basdemir, Husnu Deniz
Scattered field by a wedge that is surrounded by isorefractive media is analyzed. A series-based method is introduced and applied to the wedge problem with soft boundary condition. The fields are examined numerically. The numerical results show that the proposed method is suitable for analysis of these kinds of problems.
Citation - WoS: 6
Citation - Scopus: 6
Scattering of Waves by a Soft-Hard Half-Plane Between Isorefractive Medium
(Taylor & Francis Ltd, 2017) Umul, Yusuf Ziya
The scattering of plane waves by a soft-hard half-plane residing between isorefractive medium is studied. The scattered geometrical optics fields are obtained by subtracting the initial geometrical optics fields from the total geometrical optics waves. The diffracted fields are determined by considering the structure of the scattered geometrical optics waves. The uniform expressions for the diffracted fields are derived. The behaviour of the total waves is investigated numerically.
Scattering of Waves by an Aperture in an Impedance Screen
(Elsevier Gmbh, Urban & Fischer verlag, 2012) Umul, Yusuf Ziya
The transmission and diffraction of waves by an aperture in an impedance screen is investigated. The Senior's solution of the scattering problem of waves by an impedance half-plane is transformed into a physical optics type integral. The obtained method is applied to the transmission problem of waves by a slit in an impedance screen. The results are compared with the aperture problem in black and conducting screens numerically. (C) 2012 Elsevier GmbH. All rights reserved.
Citation - WoS: 7
Citation - Scopus: 8
The Theory of the Boundary Diffraction Wave for Wedge Diffraction
(Taylor & Francis Ltd, 2008) Umul, Yusuf Z.
A new potential function, line integration which gives the edge diffracted fields, is constructed for wedge diffraction by using the method of modified theory of physical optics. The surface integrals are transformed into line integrals by the technique of asymptotic reduction. As an application of the novel potential function, the diffracted field is obtained for the geometry of a wedge for arbitrary incidence of plane waves.

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