Güncel Gönderiler: Elektronik ve Haberleşme Mühendisliği Bölümü Yayın Koleksiyonu

  • An online adaptive cooperation scheme for spectrum sensing based on a second-order statistical method 
    Yarkan, Serhan; Töreyin, Behçet Uğur; Qaraqe, Khalid A.; Çetin, A. Enis (IEEE-Inst Electrical Electronics Engineers Inc, 2012-02)
    Spectrum sensing is one of the most important features of cognitive radio (CR) systems. Although spectrum sensing can be performed by a single CR, it is shown in the literature that cooperative techniques, including multiple ...
  • Scattering of waves by an aperture in an impedance screen 
    Umul, Yusuf Ziya (Elsevier GMBH, 2012)
    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 ...
  • The method of the boundary diffraction wave for impedance surfaces 
    Umul, Yusuf Ziya (Elsevier Science Bv, 2012-03-15)
    The line integral of the boundary diffraction wave theory is extended for the diffraction process of waves by the impedance surfaces with edge discontinuities. With this aim, the exact diffraction field expression of ...
  • Physical optics theory of resistive surfaces 
    Umul, Yusuf Ziya (Elsevier Science Ltd, 2012-03)
    The physical optics current is obtained from the exact solution of the scattering problem of plane waves by a resistive surface. The edge point method is used for the determination of the physical optics surface current. ...
  • Intensity fluctuations of flat-topped beam in non-Kolmogorov weak turbulence 
    Gerçekçioğlu, Hamza; Baykal, Yahya (Optical Soc Amer, 2012-09)
    Results obtained on the intensity fluctuations of flat-topped Gaussian beams in weakly turbulent non-Kolmogorov horizontal atmospheric optics links are represented. Effects on the scintillation index of the power law a ...
  • Generalized expression for optical source fields 
    Kamacıoğlu, Canan; Baykal, Yahya (Elsevier Science Ltd, 2012-09)
    A generalized optical beam expression is developed that presents the majority of the existing optical source fields such as Bessel, Laguerre-Gaussian, dark hollow, bottle, super Gaussian, Lorentz, super-Lorentz, flat-topped, ...
  • Boundary diffraction wave theory of junctions between two surfaces with different face impedances 
    Umul, Yusuf Ziya (Elsevier Science Ltd, 2012-07)
    The line integral of the boundary diffraction wave theory is derived for the diffraction process of waves by a junction between two surfaces with different face impedances. The exact solution of Maliuzhinets is used with ...
  • Multiport analysis by pade approximation 
    Şener, Göker (E M W Publishing, 2012)
    In this paper, a new method to analyze arbitrary shaped microstrip patch antennas is introduced. This method uses the multiport network model (MNM) together with a mathematical approximation called the "Pade approximation" ...
  • Scattering of plane waves by a wedge with different face impedances 
    Umul, Yusuf Ziya (Elsevier GMBH, 2012)
    The scattering process of plane waves by a wedge with different face impedances is examined in terms of the closed form series solution. A new boundary condition is derived using the solution of the reflection problem of ...
  • Extension of the maliuzhinets solution for the resistive half-plane 
    Umul, Yusuf Ziya (Wiley-Blackwell, 2012-03)
    The solution, put forward by Maliuzhinets for the impedance half-plane, is extended for the diffraction problem of plane waves by a resistive half-plane. With this aim, the Wiener-Hopf solution of the same problem is taken ...
  • Fringe waves in wedge diffraction 
    Umul, Yusuf Ziya (Elsevier GMBH, 2012)
    Explicit expressions for the non-uniform currents of the physical theory of diffraction are derived in terms of Fresnel functions for wedge diffraction by taking into account the surface integrals of the modified theory ...
  • The physical optics integral of creeping waves 
    Umul, Yusuf Ziya (Taylor&Francis Ltd, 2012)
    The creeping waves, occurring in surface diffraction, are expressed as a physical optics surface integral. The scattering geometry and the implications of the surface integral are investigated in the context of the diffraction ...
  • Propagation of an Airy beam through the atmosphere 
    Ji, X.L.; Eyyuboğlu, Halil T.; Ji, Guangming; Xiaoling, Ji (Optical Soc Amer, 2013-01-28)
    In this paper, the effect of thermal blooming of an Airy beam propagating through the atmosphere is examined, and the effect of atmospheric turbulence is not considered. The changes of the intensity distribution, the ...
  • Scintillation properties of a truncated flat-topped beam in a weakly turbulent atmosphere 
    Liu, Xianlong; Liang, Chunhao; Yuan, Yangsheng; Cai, Yangjian; Eyyuboğlu, Halil T. (Elsevier Science Ltd, 2013-02)
    We derive derive an explicit expression for the scintillation index of a truncated flat-topped (FT) beam in a weakly turbulent atmosphere. Under suitable conditions, the derived formula reduces to the expression for the ...
  • Speckle contrast for flat-topped field profiles 
    Baykal, Yahya (Elsevier Science Ltd, 2013-02)
    Speckle contrast is evaluated for flat-topped field profiles where the characterization and evaluation of speckle contrast are based on mathematical formulation and theoretical parameter variation. The speckle field which ...
  • Partially coherent Airy beam and its propagation in turbulent media 
    Eyyuboğlu, Halil T.; Sermutlu, Emre (Springer, 2013-03)
    The properties of partially coherent Airy beam propagating in turbulent media are investigated. Firstly the variations in the intensity profile and the location of the Airy beam peak with respect to dislocation and width ...
  • A new representation of the Kirchhoffs diffraction integral 
    Umul, Yusuf Ziya (Elsevier Science Bv, 2013-03-15)
    The diffraction integral of Kirchhoff is rearranged according to its integral boundaries. The new approach is based on the theory of the edge dislocation waves and provides a more correct field representation for the ...
  • Scintillation behavior of Airy beam 
    Eyyuboğlu, Halil T. (Elsevier Science Ltd, 2013-04)
    We make an analysis on scintillation behavior of Airy beam using the Rytov method. To this end, scintillation index is formulated for a single receiver coordinate location. Area scintillation expressions are also derived. ...
  • Impedance surface diffraction analysis for a strip with the boundary diffraction wave theory 
    Başdemir, Hüsnü Deniz (Elsevier GMBH, 2013)
    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 ...
  • Effect of spatial coherence on the scintillation properties of a dark hollow beam in turbulent atmosphere 
    Yuan, Yangsheng; Chen, Yahong; Liang, Chunhao; Cai, Yangjian; Baykal, Yahya (Springer, 2013-03)
    With the help of a tensor method, we derive an explicit expression for the on-axis scintillation index of a circular partially coherent dark hollow (DH) beam in weakly turbulent atmosphere. The derived formula can be applied ...