Parametric nonlinear lumped element model for circular CMUTs in collapsed mode

Aydogdu, Elif; Ozgurluk, Alper; Atalar, Abdullah; Köymen, H.

doi:10.1109/tuffc.2014.6689785

Cited by 17 publications

(17 citation statements)

References 24 publications

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“…Throughout the electromechanical coupling process, the pull-in characteristics are of great significance [6]. Different analyses and modeling approaches can be found in the literatures [7,8]. Most studies [5,9,10] treat CMUTs as rigid plates in open air in their analysis, with a uniform velocity profile across the CMUT surface.…”

Section: Introductionmentioning

confidence: 99%

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Pull-In Analysis of the Flat Circular CMUT Cell Featuring Sealed Cavity

Zhang¹,

Zhang

Du³

et al. 2015

Mathematical Problems in Engineering

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Capacitive micromachined ultrasonic transducers (CMUTs) are one of the appealing MEMS devices. Most studies treat CMUTs as rigid plates vibrating in open air, ignoring the mechanical boundary conditions for simplification and resulting in cumulative errors in coupled fields. This paper presents a new analytical model for the pull-in characteristics of the flat circular CMUT cell featuring sealed cavity. Utilizing the plate theory coupled with Boyle’s law, the paper establishes a strong relation between the pressures inside the sealed cavity and the pull-in characteristics for the first time. Not only did we point out that the existence of the pressure inside the sealed cavity cannot be omitted, but we also quantified the direct effect of the pressure ratios on the pull-in phenomenon. The pull-in voltages increase while the pull-in ratios decrease with the pressure ratios of the pressure inside the sealed cavity to the ambient pressure. The proposed calculation process delivers a good approximation of the pull-in voltages and displacements, which are consistent with COMSOL simulation results. Particularly, the percentage error of our calculation process is 6.986% for the worst case. Therefore, our proposed analytical model accurately and efficiently predicts the pull-in characteristics and this paper offers new perspectives and reference value in designing and modeling the CMUTs.

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Section: Introductionmentioning

confidence: 99%

“…. The maximum deflections and the average deflections for different pressures inside the sealed cavity are calculated by(6),(7) and simulated by FEM. The deflections and the relative errors between the analytical and FEM simulations are demonstrated inFigures 9 and 10.…”

mentioning

confidence: 99%

Pull-In Analysis of the Flat Circular CMUT Cell Featuring Sealed Cavity

Zhang¹,

Zhang

Du³

et al. 2015

Mathematical Problems in Engineering

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“…A static analysis of CMUT can be done using the normalized form of the Timoshenko's equation [12], [13]. We summarize this method in Appendix A for completeness.…”

Section: Analysis Of Collapsed Cmutmentioning

confidence: 99%

“…To avoid a large set of collapse bending profile calculations for each different CMUT design, we start with the normalized form of Timoshenko's Eq. (3) in [12]:…”

Section: Appendix a Static Analysis Of Collapsed Mode Cmutmentioning

confidence: 99%

Optimization of a Collapsed Mode CMUT Receiver for Maximum Off-Resonance Sensitivity

Khan

Tasdelen

et al. 2018

J. Microelectromech. Syst.

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We propose an airborne collapse capacitive micromachined ultrasonic transducer (CMUT) as a practical viable ultrasound transducer capable of providing a stable performance at the off-resonance frequencies. Traditional practice is to bias the CMUT plate close to collapse voltage to achieve high coupling coefficient and sense the incoming ultrasound as an open-circuit receive voltage signal of the transducer or shortcircuit receive current (SCRC). Maintaining CMUT plate in the vicinity of collapse threshold is rather difficult. In this paper, an analytic approach to design an airborne collapsedmode CMUT for maximum off-resonance sensitivity is presented. We use small-signal circuit model to evaluate the performance of a collapsed CMUT for varying operating conditions. CMUT operational parameters that yield the highest off-resonance SCRC are directly obtained from performance design curves. Collapsed CMUT plate is then biased in a critical biasing region that produces a stable and maximum off-resonance sensitivity. We experimentally verify and measure a stable sensitivity of a fabricated collapsed CMUT cell of −60 dB V/Pa at 100 kHz when biased between 50 to 65 V. We characterize our linear circuit model performance against the measured performance of collapsed CMUT in air within 4-dB tolerance. [2018-0058] Index Terms-CMUT, collapsed CMUT sensitivity, critical biasing region, off-resonance, small-signal circuit model. I. INTRODUCTION O WING to standard silicon integrated circuit (IC) fabrication technology and potential for integration with electronics, CMUTs have proved to be a viable technology in medical ultrasound. For example, the first pulse-echo 128-element, 1-D linear CMUT array was fabricated using simple photolithography process and was characterized with a wider bandwidth and higher sensitivity than piezoelectric ceramics in 2001 [1]. Commercial scanners using 1-D CMUT arrays are also reported to have produced clinical-quality

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“…This study aims at modeling of a collapsed mode CMUT array in a similar manner. In our previous studies we have obtained a parametric, large signal lumped element model for the single CMUT in collapsed mode [2].…”

Section: Introductionmentioning

confidence: 99%

Lumped element modeling of CMUT arrays in collapsed mode

Aydogdu

Ozgurluk

Atalar

et al. 2014

2014 IEEE International Ultrasonics Symposium

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Abstract-This study focuses on modeling collapsed mode operation 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, the mutual radiation impedance is presented for the collapsed mode, and a large signal model for a CMUT array is obtained for simulating the operation in both uncollapsed and collapsed modes. For faster computation, a small signal model for a CMUT cell is derived by linearizing the collapsed mode operation at a given bias point, and the computation time is reduced significantly. Using this model we are able to simulate a large array of collapsed CMUT cells.

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Parametric nonlinear lumped element model for circular CMUTs in collapsed mode

Cited by 17 publications

References 24 publications

Pull-In Analysis of the Flat Circular CMUT Cell Featuring Sealed Cavity

Pull-In Analysis of the Flat Circular CMUT Cell Featuring Sealed Cavity

Optimization of a Collapsed Mode CMUT Receiver for Maximum Off-Resonance Sensitivity

Lumped element modeling of CMUT arrays in collapsed mode

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