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A CMUT front-end for high performance portable ultrasound medical imaging is proposed. Designed for CMUTs operating in the 1–15 MHz range, it comprises a 100-V TX driver, a high voltage T/R switch and an ultra-low-power RX amplifier. The impact of the large parasitic capacitances of high-voltage devices, responsible for SNR degradation, is minimized by careful design and dedicated circuit techniques...
Optical fingerprint scanners suffer from limited depth of penetration and are particularly sensitive to the surface conditions of the skin. Fingerprint scanners based on ultrasounds offer the possibility to explore the surface and the underlying tissues of the finger and to detect blood flow, leading to enhanced robustness and reliability in biometric applications. Capacitive Micromachined Ultrasonic...
In this work the moving linear array technique has been used to perform 3D ecographic images of different human hands, in order to evaluate this technique to biometric recognition purposes. This technique could be considered as a possible evolution and complement of the classical optical hand geometry technique, as it allows the measurements and analysis of the internal hand region. A commercial echografic...
This paper presents the manufacturing of a flexible 192-elements curvilinear CMUT array developed using our patented reverse fabrication process. In this process the silicon nitride CMUT membranes are surface micromachined over a silicon substrate such that the non-radiating surface of the transducer corresponds to the last layer deposited, while the radiating membranes are uncovered by completely...
Real-time 3D ultrasound imaging is based on volumetric beam steering and sweeping. Transducer capable to perform volumetric beamforming for medical imaging are typically two dimensional arrays of thousands of active elements. Electronic multiplexing and pre-beamforming is necessary in order to interface such arrays to conventional ultrasound scanners. This paper describes an alternative approach for...
The electrical and mechanical behavior of cMUTs is currently under investigation. The mechanical characteristics of the membranes as well as the air-gap size determine the sensitivity, the maximum pressure level and the operating frequencies of cMUT devices. In this work, we report on a novel multilayer cMUT vibrating structure made of a stack of flexural membrane layers, conveniently interconnected...
Acoustic interactions occur between the membranes of capacitive micromachined ultrasonic transducers (CMUTs) in liquid-coupled operation, resulting in the excitation of spurious modes with a degradation of the output pressure. In pulse-echo operation of CMUT linear arrays for medical imaging, the acoustic interaction effects manifest as oscillation tails straight after the pulse signal and the echo...
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