Capacitive micromachined ultrasonic transducers and their application

Buhrdorf, A.; Ahrens, O.; Binder, J.

doi:10.1109/ultsym.2001.991873

Cited by 16 publications

(15 citation statements)

References 11 publications

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“…Introduction C apacitive micromachined ultrasonic transducers (cMUTs) [1]- [3] have the potential of replacing piezoelectric transducers in many areas. The applications include air-coupled nondestructive testing [4], [5], medical imaging [6], [7], three-dimensional (3-D) immersion imaging with 2-D transducer arrays [8], flow meters, level meters, position and distance measurements and microphones.…”

mentioning

confidence: 99%

Optimization of the gain-bandwidth product of capacitive micromachined ultrasonic transducers

Ölçüm

Senlik

Atalar

2005

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Abstract-Capacitive micromachined ultrasonic transducers (cMUT) have large bandwidths, but they typically have low conversion efficiencies. This paper defines a performance measure in the form of a gain-bandwidth product and investigates the conditions in which this performance measure is maximized. A Mason model corrected with finite-element simulations is used for the purpose of optimizing parameters. There are different performance measures for transducers operating in transmit, receive, or pulse-echo modes. Basic parameters of the transducer are optimized for those operating modes. Optimized values for a cMUT with silicon nitride membrane and immersed in water are given. The effect of including an electrical matching network is considered. In particular, the effect of a shunt inductor in the gain-bandwidth product is investigated. Design tools are introduced, which are used to determine optimal dimensions of cMUTs with the specified frequency or gain response.

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mentioning

confidence: 99%

Optimization of the gain-bandwidth product of capacitive micromachined ultrasonic transducers

Ölçüm

Senlik

Atalar

2005

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…The main dimensions are reported in TABLE I. (1) starting from the application of the Newton's law to the membrane in the Laplace domain, the displacement can be evaluated as…”

Section: A Device Working Principlementioning

confidence: 99%

“…gesture recognition, object detection, nondestructive evaluation and gas-flow metering [1]. The recent progress of MEMS technologies allowed the fabrication of sealed cavities in surface micromachining [2], making cMUTs a low-cost, small-size competitive alternative to piezoelectric transducers.…”

Section: Introductionmentioning

confidence: 99%

Characterization and operation of different cMUT membranes in air

Caspani

Langfelder

Minotti

et al. 2013

2013 IEEE International Ultrasonics Symposium (IUS)

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Capacitive micromachined ultrasonic transducers (cMUT) have emerged as an alternative technology to piezoelectric transducers. The paper presents characterization measurements of several membranes with different geometries and materials, aimed at an optimization of the membrane configuration for different applications. In parallel, suitable testing and readout electronics have been developed. We report electro-mechanical measurements and in-air uncoupled testing of devices fabricated in a dedicated process, appropriate for shortrange ultrasound transmission.

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“…Figure 23 shows a schematic depiction of how phononic crystal waveguides can be used to decouple the transducer from the aperture in acoustic imaging applications. In the figure, the signals from an array of large, high dynamic range capacitive micromachined ultrasonic transducers (cMUT) [42] (the use of piezoelectric transducer technology [43] is equally applicable here) are routed and focused to a group of small emitting points or apertures by a set of phononic crystal waveguides. The waveguiding operation is reversed in the return or sensing direction allowing for a more densely packed acoustic array capable of higher image resolution.…”

Section: Phononic Crystal Waveguidesmentioning

confidence: 99%

Research on micro-sized acoustic bandgap structures.

Fleming¹,

McCormick²,

Su³

et al. 2010

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Phononic crystals (or acoustic crystals) are the acoustic wave analogue of photonic crystals. Here a periodic array of scattering inclusions located in a homogeneous host material forbids certain ranges of acoustic frequencies from existence within the crystal, t hus creating what are known as acoustic (or phononic) bandgaps. The vast majority of phononic crystal devices reported prior to this LDRD were constructed by hand assembling scattering inclusions in a lossy viscoelastic medium, predominantly air, water or epoxy, resulting in large structures limited to frequencies below 1 MHz. Under this LDRD, phononic crystals and devices were scaled to very (VHF: 30-300 MHz) and ultra (UHF: 300-3000 MHz) high frequencies utilizing finite difference time domain (FDTD) mo deling, microfabrication and micromachining technologies. This LDRD developed key breakthroughs in the areas of micro-phononic crystals including physical origins of phononic crystals, advanced FDTD modeling and design techniques, material co nsiderations, microfabrication processes, characterization methods and device structures. Micro-phononic crystal devices realized in low-loss solid materials were emphasized in this work due to their potential applications in radio frequency co mmunications and acoustic imaging for medical ultrasound and nondestructive testing. The results of the advanced modeling, fabrication and integrated transducer designs were t hat this LDRD produced the 1 st measured phononic crystals and phononic crystal devices (waveguides) operating in the VHF (67 MHz) and UHF (937 MHz) frequency bands and est ablished Sandia as a world leader in the area of micro-phononic crystals. 4 AcknowledgementsThe authors would like to acknowledge the memory of our late colleague and friend Jim Fleming. It was Jim's vision to pursue a research program in the area of acoustic bandgap crystals and his vision lives on today through the team he assembled. The authors would like that thank the MDL staff at Sandia National Laboratories including Jim Stevens for his work developing the AlN transducer film, Craig Nakakura for his work on AlN etching, Keith Yoneshige for his work supporting the tungsten chemical mechanical polish (CMP) and Todd Bauer and Rob Jarecki for their work on process and etch development.

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Capacitive micromachined ultrasonic transducers and their application

Cited by 16 publications

References 11 publications

Optimization of the gain-bandwidth product of capacitive micromachined ultrasonic transducers

Optimization of the gain-bandwidth product of capacitive micromachined ultrasonic transducers

Characterization and operation of different cMUT membranes in air

Research on micro-sized acoustic bandgap structures.

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