Now showing items 1-20 of 20

    • Autonomous navigation of robotic units in mobile sensor network 

      Nazlibilek, S. (2012)
      This work is motivated by the problem of detecting buried anti-tank and anti-personnel mines in roads or some border regions. The problem is tried to be solved by use of small mobile robotic sensors and their some abilities ...
    • Bandwidth, power and noise considerations in airborne cMUTs 

      Senlik, M.N.; Olcum, S.; Köymen H.; Atalar, Abdullah (2009)
      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 ...
    • Circuit theoretical method for efficient finite element analysis of acoustical problems 

      Ekinci, A. S.; Atalar, Abdullah (IEEE, 1998)
      In the last decade, there has been an outstanding improvement in the computer aided design tools for VLSI circuits regarding solution times and the circuit complexity. This study proposes formulating the acoustic field ...
    • Deep-collapse operation of capacitive micromachined ultrasonic transducers 

      Olcum, S.; Yamaner F. Y.; Bozkurt, A.; Atalar, Abdullah (IEEE, 2011)
      Capacitive micromachined ultrasonic transducers (CMUTs) have been introduced as a promising technology for ultrasound imaging and therapeutic ultrasound applications which require high transmitted pressures for increased ...
    • Directional processing of ultrasonic arc maps and its comparison with existing techniques 

      Barshan, B.; Altun, K. (2007)
      Directional maximum (DM) technique for processing ultrasonic arc maps (UAMs) is proposed and compared to existing techniques. It employs directional processing in extracting the map of the environment from UAMs. DM aims ...
    • An equivalent circuit for collapse operation mode of CMUTs 

      Olcum, S.; Yamaner F.Y.; Bozkurt, A.; Koymen H.; Atalar, Abdullah (2010)
      Collapse mode of operation of the capacitive mi-cromachined ultrasonic transducers (CMUTs) was shown to be a very effective way for achieving high output pressures. However, no accurate model exists for understanding the ...
    • Experimental characterization of capacitive micromachined ultrasonic transducers 

      Olcum, S.; Atalar, Abdullah; Köymen H.; Oguz, K.; Senlik, M.N. (2007)
      In this paper, capacitive micromachined ultrasonic transducers are fabricated using a sacrificial surface micromachining process. A testing procedure has been established in order to measure the absolute transmit and receive ...
    • Fast processing techniques for accurate ultrasonic range measurements 

      Barshan, B. (Institute of Physics Publishing, 2000)
      Four methods of range measurement for airborne ultrasonic systems - namely simple thresholding, curve-fitting, sliding-window, and correlation detection - are compared on the basis of bias error, standard deviation, total ...
    • Frequency optimization in high intensity focused ultrasound 

      Yetik, H.; Ariyurek, C.; Bozkurt, A.; Ergun, A. S. (IEEE Computer Society, 2014)
      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 ...
    • Interaction between a cMUT cell and a liquid medium around the parallel resonance frequency 

      Senlik, M.N.; Atalar, Abdullah; Olcum, S. (2007)
      In this paper, we present how a capacitive micromachined ultrasonic transducer (cMUT) couples to the immersion medium, based on an accurate parametric model. We show that the velocity of cMUT membrane can be written as a ...
    • Lumped element modeling of CMUT arrays in collapsed mode 

      Aydogdu, E.; Ozgurluk, A.; Atalar, Abdullah; Koymen H. (IEEE Computer Society, 2014)
      This study focuses on modeling collapsed modeoperation of CMUT arrays, and obtaining a small signal lumped element model for collapsed mode operation. Having the large signal model for single CMUT from previous studies, ...
    • Modeling the effect of subsurface interface defects on contact stiffness for ultrasonic atomic force microscopy 

      Sarioglu, A. F.; Atalar, Abdullah; Degertekin, F. L. (AIP Publishing LLC, 2004)
      We present a model predicting the effects of mechanical defects at layer interfaces on the contact stiffness measured by ultrasonic atomic force microscopy sAFMd. Defects at subsurface interfaces result in changes at the ...
    • A new detection method for capacitive micromachine ultrasonic transducers 

      Ergun, A. S.; Temelkuran, B.; Ozbay, E.; Atalar, Abdullah (IEEE, 2001)
      Capacitive micromachine ultrasonic transducers (cMUT) have become an alternative to piezoelectric transducers in the past few years. They consist of many small circular membranes that are connected in parallel. In this ...
    • A novel equivalent circuit model for CMUTs 

      Oguz H.K.; Olcum, S.; Senlik, M.N.; Atalar, Abdullah; Köymen H. (2009)
      A nonlinear equivalent circuit for immersed transmitting capacitive micromachined ultrasonic transducers (CMUTs) is presented. The velocity profile across the CMUT surface maintains the same form over a wide frequency ...
    • A novel fiber laser development for photoacoustic microscopy 

      Yavas, S.; Aytac-Kipergil, E.; Arabul, M.U.; Erkol H.; Akcaalan O.; Eldeniz, Y.B.; Ilday F.O.; Unlu, M.B. (2013)
      Photoacoustic microscopy, as an imaging modality, has shown promising results in imaging angiogenesis and cutaneous malignancies like melanoma, revealing systemic diseases including diabetes, hypertension, tracing drug ...
    • Optimizing CMUT geometry for high power 

      Yamaner F.Y.; Olcum, S.; Bozkurt, A.; Koymen H.; Atalar, Abdullah (2010)
      Capacitive micromachined ultrasonic transducers (CMUTs) have demonstratedvarious advantages over piezoelectric transducers. However, current CMUT designsproduce low output pressures with high harmonic distortions. Optimizing ...
    • Radiation impedance and equivalent circuit for immersed CMUT array element 

      Senlik, M.N.; Atalar, Abdullah; Koymen H.; Olcum, S. (2006)
      In this paper, we present equivalent circuit for immersed capacitive micromachined ultrasonic transducers (cMUT), based on an accurate parametric model. We also present an accurate approximation for the radiation impedance ...
    • Radiation impedance of an array of circular capacitive micromachined ultrasonic transducers 

      Senlik, M. N.; Olcum, S.; Köymen, H.; Atalar, Abdullah (IEEE, 2010)
      The radiation impedance of a capacitive micromachined ultrasonic transducer (cMUT) with a circular membrane is calculated analytically using its velocity profile for the frequencies up to its parallel resonance frequency ...
    • Silicon micromachined ultrasonic immersion transducers 

      Soh, H. T.; Ladabaum, I.; Atalar, Abdullah; Quate, C. F.; Khuri-Yakub, B. T. (A I P Publishing LLC, 1996-12-09)
      Broadband transmission of ultrasound in water using capacitive, micromachined transducers is reported. Transmission experiments using the same pair of devices at 4, 6, and 8 MHz with a signal‐to‐noise ratio greater than ...
    • Wafer bonded capacitive micromachined underwater transducers 

      Olcum, S.; Oǧuz, K.; Şenlik, M.N.; Yamaner F.Y.; Bozkurt, A.; Atalar, Abdullah; Köymen H. (2009)
      In this work we have designed, fabricated and tested CMUTs as underwater transducers. Single CMUT membranes with three different radii and 380 microns of thickness are fabricated for the demonstration of an underwater CMUT ...