Reduced-gap CMUT implementation in PolyMUMPs for air-coupled and underwater applications

Tawfik, H. H.; Alsaiary, Tariq; Elsayed, Mohannad Y.; Nabki, Frédéric; El-Gamal, M.N.

doi:10.1016/j.sna.2019.05.009

Cited by 13 publications

(4 citation statements)

References 13 publications

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“…Currently, MUTs can be categorized into two types: capacitive and piezoelectric micromachined ultrasonic transducers (CMUTs and PMUTs) 25 . Compared to PMUTs, CMUTs take advantage of a high electromechanical coupling coefficient (~85%; 1-6% for PMUTs), wide bandwidth (~150%) and high receiving sensitivity [26][27][28][29][30][31] (16.6 mV/Pa) and have been widely used in 3D ultrasonic imaging, ultrasonic figure printing and range finding 32,33 . Most recently, CMUTs demonstrated successful use in blood flow velocity measurement by ultrasonic Doppler techniques because of their superior performance in comparison with their conventional counterparts 34 .…”

Section: Introductionmentioning

confidence: 99%

Noninvasive fluid bubble detection based on capacitive micromachined ultrasonic transducers

Yuan

et al. 2023

Microsyst Nanoeng

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Ultrasonic fluid bubble detection is important in industrial controls, aerospace systems and clinical medicine because it can prevent fatal mechanical failures and threats to life. However, current ultrasonic technologies for bubble detection are based on conventional bulk PZT-based transducers, which suffer from large size, high power consumption and poor integration with ICs and thus are unable to implement real-time and long-term monitoring in tight physical spaces, such as in extracorporeal membrane oxygenation (ECMO) systems and dialysis machines or hydraulic systems in aircraft. This work highlights the prospect of capacitive micromachined ultrasonic transducers (CMUTs) in the aforementioned application situations based on the mechanism of received voltage variation caused by bubble-induced acoustic energy attenuation. The corresponding theories are established and well validated using finite element simulations. The fluid bubbles inside a pipe with a diameter as small as 8 mm are successfully measured using our fabricated CMUT chips with a resonant frequency of 1.1 MHz. The received voltage variation increases significantly with increasing bubble radii in the range of 0.5–2.5 mm. Further studies show that other factors, such as bubble positions, flow velocities, fluid medium types, pipe thicknesses and diameters, have negligible effects on fluid bubble measurement, demonstrating the feasibility and robustness of the CMUT-based ultrasonic bubble detection technique.

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Section: Introductionmentioning

confidence: 99%

Noninvasive fluid bubble detection based on capacitive micromachined ultrasonic transducers

Yuan

et al. 2023

Microsyst Nanoeng

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“…Therefore, it is worthwhile to devise a new approach to achieve a compact CMUT element with a low resonant frequency and a low collapse voltage. The work in [ 9 ] presented a reduced CMUT structure with a relatively low bias voltage and a high frequency for air-coupled as well as immersed applications; it demonstrated a four-fold reduction in the bias voltage for a constant membrane displacement. Recently, collapse-mode operation CMUTs have gained a lot of attention owing to their increased electric field strength which results in very high pressure output and better efficiency [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Design and Implementation of Low-Voltage Tunable Capacitive Micro-Machined Transducers (CMUT) for Portable Applications

2022

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Capacitive micromachined ultrasonic transducers (CMUT) are MEMS-based transducers with advantages over conventional ultrasonic transducers, such as their small size, the ease of integration with semiconductor electronics, and batch fabrication. In this study, the effect of different membrane topologies on the displacement, resonant frequency, and output pressure of the CMUT membrane is investigated in the transmission mode in an air environment. A novel structural-support feature, the rocker stem, is introduced, where the membrane is weakly held to the substrate in order to minimize mechanical constraints. Four different CMUT topologies are designed and assessed to analyze the impacts of topological variations. A new CMUT array configuration is also designed to provide an approach for maximizing CMUT density. This study aims to contribute to efficient CMUT design and the determination of optimum structural parameters for portable applications in air.

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“…More and more researchers in the world pay attention to the CMUT because of its wide application. In (Tawfik et al, 2019), a CMUT with a reduced-gap architecture implemented in the polysilicon multiuser MEMS processes (PolyMUMPs) technology is introduced. An improved lumped element parametric model for immersed CMUT is presented in (Kemal et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Research on optimization sparse method for capacitive micromachined ultrasonic transducer array: heuristic algorithm

Zhang

Shao

et al. 2021

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Purpose Because of the small size and high integration of capacitive micromachined ultrasonic transducer (CMUT) component, it can be made into large-scale array, but this lead to high hardware complexity, so the purpose of this paper is to use less elements to achieve better imaging results. In this research, an optimized sparse array is studied, which can suppress the side lobe and reduce the imaging artifacts compared with the equispaced sparse array with the same number of elements. Design/methodology/approach Genetic algorithm is used to sparse the CMUT linear array, and Kaiser window apodization is added to reduce imaging artifacts, the beam pattern and peak-to-side lobe ratio are calculated, point targets imaging comparisons are performed. Furthermore, a 256-elements CMUT linear array is used to carry out the imaging experiment of embedded mass and forearm blood vessel, and the imaging results are compared quantitatively. Findings Through the imaging comparison of embedded mass and forearm blood vessel, the feasibility of optimized sparse array of CMUT is verified, and the purpose of reducing the hardware complexity is achieved. Originality/value This research provides a basis for the large-scale CMUT array to reduce the hardware complexity and the amount of calculation. At present, the CMUT array has been used in medical ultrasound imaging and has huge market potential.

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Reduced-gap CMUT implementation in PolyMUMPs for air-coupled and underwater applications

Cited by 13 publications

References 13 publications

Noninvasive fluid bubble detection based on capacitive micromachined ultrasonic transducers

Noninvasive fluid bubble detection based on capacitive micromachined ultrasonic transducers

Design and Implementation of Low-Voltage Tunable Capacitive Micro-Machined Transducers (CMUT) for Portable Applications

Research on optimization sparse method for capacitive micromachined ultrasonic transducer array: heuristic algorithm

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