Now showing items 1-20 of 164

    • A 128-bit microprocessor compatible programmable correlator chip for use in synchronous communication 

      Ungan, İ. Enis; Topçu, Satılmış; Atalar, Abdullah (IEEE, 1989)
      A single-chip microprocessor-compatible 128-b correlator is designed and implemented in a 3-μm M2CMOS process. Full-custom design techniques are applied to achieve the best tradeoff among chip size, speed, and power ...
    • Accurate and process-tolerant resistive load 

      Sütbaş, Batuhan; Özbay, Ekmel; Atalar, Abdullah (IEEE, 2020)
      Resistive terminations cannot preserve high-quality matching at high frequencies due to the parasitic effects of the nonideal resistor. Moreover, resistance values of the termination resistors in integrated circuits are ...
    • Acoustic microscopy with mechanical scanning—A review 

      Quate, C. F.; Atalar, Abdullah; Wickramasinghe, H. K. (IEEE, 1979-08)
      Acoustic waves in liquids are known to have wavelengths comparable to that of visible light if the frequency is in the gigahertz range. The phenomena of Brillouin scattering in liquids is based on such waves. In helium ...
    • Acoustic microscopy: resolution of subcellular detail 

      Johnston, R. N.; Atalar, Abdullah; Heiserman, J.; Jipson, V.; Quate, C. F. (National Academy of Sciences, 1979-07)
      Recent advances now permit the use of scanning acoustic microscopy for the analysis of subcellular components. By sequential viewing of identified fixed cells with acoustic, light, and electron microscopy, we have established ...
    • Acoustical tuning of CMUT receiver arrays 

      Taşdelen, Akif Sinan; Atalar, Abdullah; Enhoş, Kerem; Köymen, Hayrettin (IEEE, 2016)
      Cell placement in an element and structural modifications on the array baffle significantly change the bandwidth, band shape and signal to noise ratio of a CMUT receiver array. In this paper, optimum receiver performance ...
    • Analysis and design of an interdigital cantilever as a displacement sensor 

      Yaralioglu, G. G.; Atalar, Abdullah; Manalis, S. R.; Quate, C. F. (A I P Publishing LLC, 1998-06-15)
      The interdigital (ID) cantilever with two sets of interleaving fingers is an alternative to the conventional cantilever used in the atomic force microscope (AFM). In this paper we present a detailed analysis of the ...
    • Analysis of mutual acoustic coupling in CMUT arrays using an accurate lumped element nonlinear equivalent circuit model 

      Oğuz, H.Kağan; Atalar, Abdullah; Köymen, Hayrettin (2012)
      We use an accurate nonlinear equivalent circuit model to analyze CMUT arrays with multiple cells, where every cell in the array is coupled to other cells at their acoustic terminals through a mutual radiation impedance ...
    • Analysis of tip-sample interaction in tapping-mode atomic force microscope using an electrical circuit simulator 

      Sahin, O.; Atalar, Abdullah (AIP Publishing, 2001-05-07)
      We present a mechanical model for the atomic force microscope tip tapping on a sample. The model treats the tip as a forced oscillator and the sample as an elasticmaterial with adhesiveproperties. It is possible to transform ...
    • Analytic modeling of loss and cross-coupling in capacitive micromachined ultrasonic transducers 

      Bozkurt, A.; Degertekin, F. L.; Atalar, Abdullah; Khuri-Yakub, B. T. (IEEE, Piscataway, NJ, United States, 1998)
      The structural loss mechanism of capacitive micromachined ultrasonic transducer (cMUT) is investigated using finite element analysis and the normal mode theory. A single micromachined transducer membrane on an infinite ...
    • An analytical approach to the design of multiple mode rectangular cavity waveguide filters 

      Kelleci, C.; Atalar, Abdullah (Institute of Electrical and Electronics Engineers Inc., 2017)
      The multiple mode rectangular cavity structure with square corner cuts is revisited. An attempt to predict the physical dimensions of the cavity for dual mode second-order and triple mode third-order filters is made. ...
    • An angular‐spectrum approach to contrast in reflection acoustic microscopy 

      Atalar, Abdullah (A I P Publishing, 1978-11)
      The scanning acoustic microscope in the reflection mode has proved to be a rather simple and direct means for monitoring the elastic properties of a solid surface. When smooth surfaces of crystalline material are examined ...
    • 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 ...
    • Application of asymptotic waveform evaluation for time-domain analysis of nonlinear circuits 

      Topçu, S.; Atalar, Abdullah; Tan, M. A. (Taylor & Francis, 1997)
      A method is described to exploit asymptotic waveform evaluation (AWE) in the time-domain analysis of nonlinear circuits by using SPICE models for nonlinear devices such as diodes, transistors, etc. Although AWE has been ...
    • Automated parallel high-speed atomic force microscopy 

      Minne, S. C.; Yaralioglu, G.; Manalis, S. R.; Adams, J. D.; Zesch, J.; Atalar, Abdullah; Quate, C. F. (A I P Publishing LLC, 1998-05-04)
      An expandable system has been developed to operate multiple probes for the atomic force microscope in parallel at high speeds. The combined improvements from parallelism and enhanced tip speed in this system represent an ...
    • A backscattering formula for acoustic transducers 

      Atalar, Abdullah (A I P Publishing, 1980-06)
      A backscattering formula for a single transducer geometry is derived. It expresses the output voltage of the transducer in terms of the angular spectra of scalar and vector acoustic potentials on a plane. The formulation ...
    • Bandwidth improvement in a cMUT array with mixed sized elements 

      Bayram, Can; Olcum, Selim; Şenlik, Muhammed N.; Atalar, Abdullah (IEEE, 2005-09)
      A capacitive micromachined ultrasonic transducer (cMUT) is typically fabricated by concatenation of several cMUT cells with identical physical dimensions. If the membrane thickness is kept fixed, the radius of the cMUT ...
    • Bandwidth, power and noise considerations in airborne cMUTs 

      Şenlik, Muhammed N.; Olcum, Selim; Köymen, Hayrettin; Atalar, Abdullah (IEEE, 2009-09)
      Capacitive micromachined ultrasonic transducers (cMUTs) offer wider bandwidth in air due to their low mechanical impedances. The impedance mismatch between the air and transducer decreases with the smaller device dimensions ...
    • Beam steering in a half-frequency driven airborne CMUT transmitter array 

      Khan, Talha Masood; Taşdelen, Akif Sinan; Yılmaz, Mehmet; Atalar, Abdullah; Köymen, Hayrettin (IEEE Computer Society, 2019)
      An airborne Capacitive Micromachined Ultrasonic Transducer (CMUT) transmit array was designed using electromechanical modelling for unbiased airborne operation. The array elements are designed for maximum swing at 10V p-p ...
    • Bi-angular lens for material characterization 

      Yaralıoğlu, Göksen Göksenin; Atalar, Abdullah; Köymen, Hayrettin (IEEE, 1994)
      In this paper a new lens design is proposed for characterization of layered materials. Lamb wave lens employs Lamb waves for this purpose since these waves propagate along interfaces. However, below cut-off angle, the ...
    • Bilateral CMUT cells and arrays: equivalent circuits, diffraction constants, and substrate impedance 

      Köymen, Hayrettin; Atalar, Abdullah; Taşdelen, A. S. (Institute of Electrical and Electronics Engineers Inc., 2017)
      We introduce the large-signal and small-signal equivalent circuit models for a capacitive micromachined ultrasonic transducer (CMUT) cell, which has radiating plates on both sides. We present the diffraction coefficient ...