Now showing items 21-40 of 320

    • Dual polarized broadband and all dielectric partial cloaking using stacked graded index structures 

      Oner, B.B.;  Can, M.G.;  Kurt, Hamza (Optical Society Of American (OSA), 2014-08)
      We propose broadband one-dimensional optical cloaking design based on isotropic and purely dielectric non-absorbent materials. The photonic structures are formed by utilizing graded index (GRIN) concept in stacked form. ...
    • Reduced symmetry and analogy to chirality in periodic dielectric media 

      Giden, I.H.;  Turduev, M.;  Kurt, Hamza (Springer, 2014-09)
      Much attention has been paid to photonic applications based on periodic media. Meanwhile, quasi-periodic and disordered mediahave extended the research domain and provided additional novelties for manipulating and controlling ...
    • Photonic Nanojet Analysis by Spectral Element Method 

      Mahariq, I.;  Kuzuoğlu, M.;  Tarman, I.H.;  Kurt, Hamza (Institute Of Electrical And Electronics Engineers Inc., 2014-09)
      Although it is known that the spectral element method (SEM) has both high accuracy and a lower computational cost when compared with finite-element or finite-difference methods, the SEM is not widely utilized in the modeling ...
    • Graded index optical microresonators: analytical and numerical analyses 

      Dadashi, Khalil; Kurt, Hamza; Ustun, Kadir; Esen, Ramazan (Optical Soc Amer, 2014-09)
      It is known that the spectra of optical modes supported by microresonators are shape and size dependent. We have introduced an additional parameter, i.e., spatially varying refractive index, to tailor the spectra of optical ...
    • Multiple slow waves and relevant transverse transmission and confinement in chirped photonic crystals 

      Serebryannikov, Andriy E.; Cakmak, A. Ozgur; Colak, Evrim; Caglayan, Humeyra; Kurt, Hamza; Ozbay, Ekmel (Optical Soc Amer, 2014-09-08)
      The dispersion properties of rod-type chirped photonic crystals (PhCs) and non-channeled transmission in the direction of the variation of structural parameters from one cell of such a PhC to another are studied. Two types ...
    • Design of a Driver IC for an Ultrasound Catheter Ablation System 

      Bozkurt, Ayhan; Farhanieh, Omid; Roy, Rupak Bardhan; Ergün, Arif Şanlı (IEEE, 2014-10)
      High Intensity Focused Ultrasound (HIFU) is generally administered externally, or through body orifices such as the esophagus, the urethra, the uterus, or the rectum. The devices used in conventional treatment are not ...
    • An Integrated Beamforming Driver for CMUT based Ultrasound Catheter Ablation System 

      Yetik, Hasan; Ergün, Arif Şanlı; Bozkurt, Ayhan (IEEE, 2014-10)
      In CMUT based ultrasound catheter ablation systems, transducer arrays and their drivers are to be kept as small as possible due to size restrictions, while maintaining a reasonable number of channels for proper beamforming. ...
    • Frequency Optimization in High Intensity Focused Ultrasound 

      Yetik, Hasan; Ariyurek, Cemre; Bozkurt, Ayhan; Ergün, Arif Şanlı (IEEE, 2014-10)
      In high intensity focused ultrasound (HIFU) the choice of transducer frequency depends on the target depth and tissue type. At high frequencies attenuation does not permit enough acoustical power to be transmitted to the ...
    • The Impact of Transmission Power Control Strategies on Lifetime of Wireless Sensor Networks 

      Cotuk, Huseyin; Bıçakçı, Kemal; Tavlı, Bülent; Uzun, Erkam (IEEE Computer Soc., 2014-11)
      Transmission power control has paramount importance in the design of energy-efficient wireless sensor networks (WSNs). In this paper, we systematically explore the effects of various transmission power control strategies ...
    • Role of Unidirectionality and Reverse Path Length on Wireless Sensor Network Lifetime 

      Batmaz, Anil Ufuk; Yildiz, Huseyin Ugur; Tavlı, Bülent (IEEE-Inst Electrical Electronics Engineers Inc, 2014-11)
      Transceiver characteristics, asymmetric interference, and various properties of electromagnetic propagation environment create unidirectional links in wireless sensor networks (WSNs), especially in extreme environments. ...
    • Broadband one way propagation via dielectric waveguides with unequal effective index 

      Öner, B.B.; Üstün, K.; Kurt, H.; Okyay, A.K.; Turhan-Sayan, G. (Institute of Electrical and Electronics Engineers Inc., 2014-12)
      We present an efficient approach for broad band one way propagation of light by parallel and unequal dielectric waveguides leading different effective phase shifts. Three dimensional numerical simulations show that 30% ...
    • Asymmetric light transmission by using 2D PT-symmetric photonic nanostructure 

      Turduev, M.; Botey, M.; Herrero, R.; Giden, I.; Kurt, Hamza; Staliunas, K. (Institute of Electrical and Electronics Engineers Inc., 2014-12)
      We propose for the first time a simple realization of a two-dimensional Parity-Time symmetric hexagonal shaped photonic structure composed of honeycomb lattice. The structure has a symmetric periodic modulation of the ...
    • Demonstration of Individual Readout of Serially-Connected Superconducting Strip Line Detectors 

      Kamiya, Kyohei; Kita, Yuma; Kozaka, Misaki; Tanaka, Masamitsu; Fujimaki, Akira; Bozbey, Ali (IEEE, 2015)
      We report successful demonstration of individual readout of the response to an optical signal in serially-connected superconducting strip line detectors (SSLDs). Based on the numerical analysis, placement of low-pass filters ...
    • 3D imaging for ground-penetrating radars via dictionarydimension reduction 

      Duman, Muhammed; Gürbüz, Ali Cafer (TÜBİTAK, 2015)
      Ground-penetrating radar (GPR) has been widely used in detecting or imaging subsurface targets. In many applications such as archaeology, utility imaging, or landmine detection, three-dimensional (3D) images of the subsurface ...
    • Vortex Transitional Memory Developed with Nb 4-Layer, 10-kA/cm(2) Fabrication Process 

      Komura, Yuto; Tanaka, Masamitsu; Fujimaki, Akira; Nagasawa, Shuichi; Bozbey, Ali (IEEE, 2015)
      We report random access memories (RAMs) based on vortex transitional (VT) memory cell developed with the newly developed AIST 10-kA/cm(2), Nb 4-layer fabrication process, called High-Speed Standard Process (HSTP). We ...
    • Nonreciprocal light transmission in gain-loss modulated Micro ring resonators 

      Giden, I.H.; Dadashi, K.; Botey, M.; Herrero, R.; Staliunas, K.; Kurt, Hamza (IEEE Computer Society, 2015)
      We propose a new type of add-drop Micro ring resonator that is made up of gain and loss materials. In all-dielectric linear systems, light transmission is reciprocal: A symmetric transmission spectrum is observed when an ...
    • Prolonging Wireless Sensor Network Lifetime by Optimal Utilization of Compressive Sensing 

      Yildiz, Huseyin Ugur; Tavlı, Bülent (IEEE, 2015)
      In a typical Wireless Sensor Network (WSN) application, sensor nodes gather data from the environment and convey the collected data towards the base station. It is possible to perform certain signal processing operations ...
    • The Impact of Elimination of The Most Critical Node on Wireless Sensor Network Lifetime 

      Yuksel, Anil; Uzun, Erkam; Tavlı, Bülent (IEEE, 2015)
      Wireless Sensor Network (WSN) paradigm is an integral component of ubiquitous computing and Machine-to-Machine communications. Since WSNs are widely used in homeland security, military applications, next generation power ...
    • Efficient and Reliable Multicast of Data in APCO P25 Systems 

      Cigirkan, Gulay; Girici, Tolga; Yüksel, Melda (IEEE, 2015)
      In this paper, we investigate an efficient scheme for data multicasting in narrowband public safety radio systems. The proposed scheme uses fountain encoding, in order to avoid feedback messages for each individual packet. ...
    • Mode analysis and light confinement of optical rib waveguides in various air slot configurations 

      Eti, N.; Mahariq, I.; Kurt, Hamza (IEEE Computer Society, 2015)
      We present a detailed theoretical study on mode analysis and light confinement properties of rib waveguides in various air slot configurations using dielectric materials. The study starts form rectangular rib waveguide ...