Browsing by Subject "Low-drive voltages"

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    Designing efficient CMUT cells for airborne applications
    (IEEE, 2014) Ünlügedik, Aslı; Taşdelen, Akif Sinan; Atalar, Abdullah; Köymen, Hayrettin
    In this work, we study airborne CMUT cells with vacuum gap where silicon plate is operated both in elastically linear and nonlinear regimes. We report the results of a new mode of operation where the plate center swings the entire gap. The plate is kept in elastically linear region in this mode. Very large pressure levels are obtained at relatively low drive voltage levels. The operation is very efficient but the bandwidth is less than 1%. We considered operating the silicon membrane in elastically nonlinear region for larger bandwidth without sacrificing efficiency. This is achieved by employing the stiffening effect due to the atmospheric pressure. We derived the new model of the CMUT, where the membrane profile deviates from linear profile as a function of the differential static pressure on it. We present the force, the compliance models and the static analysis of stiffened CMUT cells in this work.
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    Electrically unbiased driven airborne capacitive micromachined ultrasonic transducer design
    (IEEE, 2012) Ünlügedik, Aslı; Atalar, Abdullah; Kocabaş, Coşkun; Oğuz, H. Kağan; Köymen, Hayrettin
    We present a design method for airborne capacitive micromachined ultrasonic transducers (CMUT). We use an equivalent lumped element circuit to model both electrical and mechanical properties of CMUT and analyze it in frequency domain using harmonic balance approach. We use this method to design CMUTs for large transmitted power generation at low drive voltage amplitude. We determine the dimensions of an airborne CMUT using the proposed method that works at 30 kHz with 5 mm radius, 240 μm membrane thickness and 11.8 μm effective gap height. The CMUT is designed such that an atmospheric depression of 70% of effective gap height is maintained. © 2012 IEEE.