Now showing items 1-14 of 14

    • Analysis of finite arrays of axially directed printed dipoles on electrically large circular cylinders 

      Ertürk, V. B.; Rojas, R. G.; Lee, K. W. (IEEE, 2004)
      Various arrays consisting of finite number of printed dipoles on electrically large dielectric coated circular cylinders are investigated using a hybrid method of moments/Green's function technique in the spatial domain. ...
    • Anisotropy sensitivity of an acoustic lens with slit aperture 

      Atalar, Abdullah; Ishikawa, I.; Ogura, Y.; Tomita, K. (IEEE, 1993)
      A conventional spherical acoustic lens is modified by restricting its aperture in the form of a slit to provide directional sensitivity. The spacing between the two parallel absorbing sheets forming the slit is adjustable ...
    • Characterization and imaging with lamb wave lens at gigahertz frequencies 

      Bozkurt, A.; Yaralioglu, G.; Atalar, Abdullah; Koymen, H.; Kramer, K. (IEEE, 1994-10)
      Lamb wave lenses with conical refracting surfaces are fabricated for use at 400 MHz and 1 GHz. The conical surfaces are ground and polished with mechanical means and they are sufficiently smooth for the frequencies of ...
    • Closed-form Green's functions for general sources and stratified media 

      Dural, G.; Aksun, M. I. (Institute of Electrical and Electronics Engineers, 1995-07)
      The closed-form Green's functions of the vector and scalar potentials in the spatial domain are presented for the sources of horizontal electric, magnetic, and vertical electric, magnetic dipoles embedded in general, ...
    • Focusing surface waves using an axicon 

      Koymen, H.; Atalar, Abdullah (A I P Publishing, 1985-12)
      Axicons are generators of waves which focus on a line. They are used in various imaging and nondestructive testing applications as bulk wave focusing devices with a very long depth of focus. In this letter, a new type of ...
    • Fresnel lamb wave and V-groove lenses with tunable mode selectivity 

      Yarahoglu, G. G.; Atalar, Abdullah; Koymen, H. (IEEE, 1995)
      The Lamb wave and V-groove lenses are distinguished by their high surface wave excitation efficiencies. However, due to the fixed incidence angle, a particular lens can only be used for materials having surface wave ...
    • Generation of focused surface waves with a solid wedge 

      Atalar, Abdullah; Koymen, H. (IEEE, 1987-10)
      Focusing of surface acoustic waves on material surfaces was achieved by axicons in liquid immersion. The system consisted of a plane acoustic wave generator obliquely insonifying a cylindrical mirror placed perpendicularly ...
    • Long-range tamm surface plasmons supported by graphene-dielectric metamaterials 

      Hajian, H.; Caglayan, H.; Ozbay, E. (American Institute of Physics Inc., 2017)
      Considering the Ohmic losses of graphene in the calculations and by obtaining exact dispersion relations of the modes, we theoretically study propagation and localization characteristics of Tamm surface plasmons supported ...
    • Nearly perfect resonant absorption and coherent thermal emission by hBN-based photonic crystals 

      Hajian, H.; Ghobadi, A.; Butun, B.; Ozbay, E. (Optical Society of America, 2017)
      In this paper, we numerically demonstrate mid-IR nearly perfect resonant absorption and coherent thermal emission for both polarizations and wide angular region using multilayer designs of unpatterned films of hexagonal ...
    • Non-universal behavior of leaky surface waves in a one dimensional asymmetric plasmonic grating 

      Vempati S.; Iqbal, T.; Afsheen, S. (American Institute of Physics Inc., 2015)
      We report on a non-universal behavior of leaky surface plasmon waves on asymmetric (Si/Au/analyte of different height) 1D grating through numerical modelling. The occurrence of the leaky surface wave was maximized (suppressing ...
    • Response of surface acoustic wave imaging systems to cylindrical inhomogeneities 

      Gunalp, N.; Baygun, B.; Surucu, F.; Atalar, Abdullah (IEEE, 1988-10)
      The authors present a theory to predict the response of a SAW (surface acoustic wave) imaging system. In particular, they calculate the response to cylindrical cavities as a function of cavity position with respect to the ...
    • Surface wave splitter based on metallic gratings with sub-wavelength aperture 

      Caglayan H.; Ozbay, E. (Optical Society of American (OSA), 2008)
      We investigated the splitting of surface electromagnetic waves trapped at the output surface of a one-dimensional metallic grating structure. The output gratings of the structure asymmetrically such that the output surfaces ...
    • Synthetic aperture imaging system using surface wave modes 

      Bozkurt, A.; Arikan, O.; Atalar, Abdullah (IEEE, 1995)
      A synthetic aperture acoustic imaging system with a novel inversion algorithm is described. Data is obtained by using a transducer insonifying the sample surface at a critical angle which is excited by a short electrical ...
    • Wave propagation in metamaterial structures and retrieval of homogenization parameters 

      Ircı, Erdinç (Bilkent University, 2007)
      Electromagnetic wave propagation in metamaterial structures (metamaterial slabs, metamaterial cylinders, metamaterial coated conducting cylinders etc.) are investigated. Scattered and transmitted electromagnetic fields ...