Alessandro Stuart Savoia | Roma Tre University, Rome, Italy (original) (raw)
Papers by Alessandro Stuart Savoia
Proceedings of the IEEE Ultrasonics Symposium
The electrical and mechanical behavior of cMUTs is currently under investigation. The mechanical ... more 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 by means of equally spaced pillars. Each membrane layer is metallized in order to apply and detect the electrical signals. A simple analytical lumped parameters model shows that a multilayer cMUT structure can achieve higher sensitivity and maximum pressure level while mantaining broadband behavior. We report finite element modeling (FEM) of possible configurations of multilayer cMUTs for broadband immersion operation in the MHz frequency range. The results obtained show enhanced sensitivity and bandwidth performances in respect of conventional cMUTs.
2006 IEEE Ultrasonics Symposium, 2006
The electrical and mechanical behavior of cMUTs is currently under investigation. The mechanical ... more 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 by
IEEE Ultrasonics Symposium, 2004, 2004
In this work, design criteria for a low-noise, wideband front-end electronics suitable for Capaci... more In this work, design criteria for a low-noise, wideband front-end electronics suitable for Capacitive Micromachined Ultrasonic Transducers (CMUTs) pulse-echo operation are given. To investigate which configuration of the receiving amplifier assures the best performance, the basic circuits of voltage and transimpedance amplifier are both analyzed, optimized and compared through PSpice simulations. Custom electronics are also realized, based on the reported analysis, and the performances are evaluated using a fabricated 64-element CMUT array.
2014 IEEE International Ultrasonics Symposium, 2014
Fig. 1. Schematic representation of the "unimorph" elementary cell structure and operating princi... more Fig. 1. Schematic representation of the "unimorph" elementary cell structure and operating principle (a) and a particular of the proposed transducer structure (b).
2007 IEEE Ultrasonics Symposium Proceedings, 2007
Real-time 3D ultrasound imaging is based on volumetric beam steering and sweeping. Transducer cap... more 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 volumetric beamforming based on a particular two dimensional array of a reduced number of elements obtained by superimposing two linear arrays on the same area. Capacitive Micromachined Ultrasonic Transducer (cMUT) technology is mentioned as a good candidate to approach the problem due to the possibility given by micromachining to fabricate arbitrarily shaped electrode patterns which define the array elements. The beamforming strategy is illustrated and assessed by means of beampattern calculations and synthetic 3D imaging formation. The resulting array is directly connectable to a standard imaging system.
The validity of cMUT technology for medical imaging applications has been proved by many authors.... more The validity of cMUT technology for medical imaging applications has been proved by many authors. The large bandwidth obtainable with capacitive Micromachined Ultrasonic Transducers (cMUT) leads to improved image resolution if compared to their piezoelectric counterpart. However cMUTs actually show lower sensitivity than piezoelectric transducers, mainly due to their non optimized design and fabrication technology. Recently, we developed in our laboratories a dual-frequency plasma-enhanced chemical-vapour-deposition (DF-PECVD) process, improving the electrical and mechanical characteristics of the silicon nitride films that we employed to fabricate cMUTs. The DF-PECVD technique makes it possible to control, with extreme precision and over a wide range of values, the stress of the grown silicon nitride film. The result is an increased cohesion and an increased resistivity of the silicon nitride film. As a consequence, the porosity of the obtained DF-PECVD nitride film is extremely reduced thus contributing to effectively sealing the underlying cavities of the cMUT membranes. The improvement of both mechanical and electrical properties of the cMUT structural layer has led to higher transmission and reception sensitivity. Using this silicon nitride deposition technique, we have fabricated 64-elements, 5 MHz echographic probes featuring 100% bandwidth and higher sensitivity characteristics leading to a remarkable improvement in the quality of the echographic images.
ABSTRACT In this work we report on the performance optimization of a recently developed high freq... more ABSTRACT In this work we report on the performance optimization of a recently developed high frequency CMUT probe. By leveraging the advantages offered by our proprietary “Reverse Fabrication Process (RFP)” CMUT technology, we have developed an efficient and reliable packaging process, useful for the fabrication of small sized ultrasound probe-heads. We have maximized the performance by connecting the CMUT probe-head to multichannel analog front-end electronic circuits housed into the probe. An experimental comparison with an equivalent piezoelectric probe, the LA435 commercialized by Esaote S.p.A. (Italy), carried out by means of pulse-echo measurements, showed superior performance for the CMUT probe. Real time in-vivo ultrasound imaging capability demonstrates the actual usability of CMUT technology for medical imaging.
2014 IEEE International Ultrasonics Symposium, 2014
In this paper, we propose a method to improve the lateral resolution and the contrast of ultrasou... more In this paper, we propose a method to improve the lateral resolution and the contrast of ultrasound images, based on the cancellation of the sole contribution due to the sidelobes, thus maintaining the original depth of field and penetration capability. In the proposed method, each scan line is obtained by compounding the signals reconstructed by two emissions. For the first one, typical aperture and apodization profile are adopted. In the second emission, the same aperture is used, but the sign of the apodization profile is inverted over the second half of the aperture. The same approach is applied in receive. In this way, the second two-way beam has a main lobe with near-zero amplitude and sidelobes close to those of the first beam. The RF echo-signals corresponding to the two emissions are demodulated and successively subtracted. The resulting signal is finally log-compressed and scan converted. Simulations and in vivo experiments show a significant improvement of both detail and contrast resolution.
2013 IEEE International Ultrasonics Symposium (IUS), 2013
Augmented Reality (AR) is the new frontier of the human-machine interfaces. A localization system... more Augmented Reality (AR) is the new frontier of the human-machine interfaces. A localization system based on coded ultrasound capable to localize and track in real time head-mounted glasses is presented. An AR system has to know the point of view of the user with a high degree of accuracy, in order to correctly superimpose supplemental information to the scene. In past works, the authors presented different prototypes of locating systems based on airborne ultrasound, fast and accurate enough for the implementation of touch-less gestural interfaces. In this work, the development of a first prototype of a modified locating system well suited to work in conjunction with AR glasses is reported.
2010 IEEE International Ultrasonics Symposium, 2010
ABSTRACT Export Date: 29 November 2012, Source: Scopus, Art. No.: 5935620
ABSTRACT In this work an experimental evaluation of the possiblity to influence and control the f... more ABSTRACT In this work an experimental evaluation of the possiblity to influence and control the fluid film forces in the gap of a lubricated journal bearing by means of a rotating travelling wave is carried out. The travellig wave is generated by two power actuators opportunely positioned on the outer surface of the bearing and electrically driven with a phase shift of 90 degrees. Each transducer is designed to work at the natural frequency of the radial nonaxisymmetrical mode 0-5 (23.6 kHz). Experimental results show that the travelling wave is capable to control the motion of an oil drop on the inner surface of the bearing and that it is capable to put in rotation a rotor layed on the drop oil via the viscous forces in the oil drop itself.
2013 IEEE International Ultrasonics Symposium (IUS), 2013
ABSTRACT In phased array systems, a partial beamforming can be carried out inside the probe to re... more ABSTRACT In phased array systems, a partial beamforming can be carried out inside the probe to reduce the number of signals to be processed by the main system. Such technique, known as micro-beamforming, involves the application of a delay-and-sum beamforming to small groups of adjacent array elements using dedicated electronics. In this paper we show that, due to the electrostatic spring-softening effect, the phase response of Capacitive Micromachined Ultrasonic Transducers (CMUTs) can be controlled by varying the bias voltage. Based on this phenomenon, we propose a phase shift micro-beamforming method of CMUT arrays. We analyze the performance obtainable by applying this method to a typical phased array configuration for medical imaging. We show that, with relatively high quality factor CMUTs that still allow broadband immersion operation, it is possible to obtain up to 90° phase shifts by varying the bias voltage. Further, by inverting the sign of the bias voltage, we show that it is possible to obtain an additional 180° phase shift. Simulation results show that, with a 40% -3 dB one-way fractional bandwidth CMUT, the grating lobe level of the transmission radiation patterns, obtained with the proposed micro-beamforming technique, may be kept below -23 dB using broadband excitation signals for maximum steering angles of ±45°.
2010 IEEE International Ultrasonics Symposium, 2010
ABSTRACT In this work, 3D ultrasonic images of the internal region of the palm ofthe human hand a... more ABSTRACT In this work, 3D ultrasonic images of the internal region of the palm ofthe human hand are presented and analyzed in order to evaluate the ultrasonictechnique for biometric recognition purposes. A commercial ultrasound imagingmachine provided with a high frequency (12 MHz) linear array has been employed.The probe is moved in the directional orthogonal to the array and at each step aB-scan is performed and stored to form a 3D matrix. The data from the the 3Dmatrix are elaborated for achieving 3D ultrasonic palmprints. The results havebeen compared with corresponding sample obtained with conventional methods andthe advantages of the proposed technique are underlined and discussed.
2013 IEEE International Ultrasonics Symposium (IUS), 2013
In recent years, the increasing usage of tablet PCs and smartphones has made obsolete the traditi... more In recent years, the increasing usage of tablet PCs and smartphones has made obsolete the traditional keyboard and mouse as input devices, replaced by multi-touch or stylus-based input solutions that are perceived as being more user-friendly. Over the past 30 years, has been shown in literature and by patents, several solutions based on different types of interaction, from optics to acoustics. Our objective is to make surfaces, also wide, which have not been designed for use as a touch-screen, in particular with the new operating systems that widely use the intuitive features of the touch-methodology, usable. The goal of the work is to realize an autonomous stylus, at low cost, capable of generating flexural waves in any surface, which can be detected with a sensors system, also simple and low-cost, with an appropriate accuracy, in order to detect the position of the stylus, both to be used as pointer, either to be used as an input device for natural writing or drawing.
2012 IEEE International Ultrasonics Symposium, 2012
In this work, an ultrasound technique for achieving 3D palm vein patterns for biometric recogniti... more In this work, an ultrasound technique for achieving 3D palm vein patterns for biometric recognition purposes is proposed and experimentally tested. Commercial ultrasound imaging machine and linear arrays have been employed. Both imaging and power Doppler analysis have been performed to detect veins. The probe is moved in the directional orthogonal to the array by an automated scanning system and at each step a a 2D frame is captured and stored to form a 3D matrix. The data from the 3D matrix are elaborated for achieving 3D ultrasonic vein patterns. The proposed technique has been applied to acquire hand vein patterns of about a dozen of distinct volunteers, which are opportunely rendered and discussed.
In this paper we present an US system simulation tool, capable to study how system performance is... more In this paper we present an US system simulation tool, capable to study how system performance is influenced by both electronic and acoustic design parameters by joining acoustic-side models with those of the transducer and front-end electronics. The implemented tool has been entirely implemented in Matalb and includes US-field, CMUT and receiver front-end models. In particular, in this work we focus on the reception chain of components and evaluate the accuracy and correct functioning of the Matlab model compared to a real electronic architecture. Results and electric simulations confirmed that our tool efficiently joins all the implemented models and is able to correctly simulate and process the received echo signals.
In modern ultrasound imaging devices, two-dimensional probes and electronic scanning allow volume... more In modern ultrasound imaging devices, two-dimensional probes and electronic scanning allow volumetric imaging of anatomical structures. When dealing with the design of such complex 3-D ultrasound (US) systems, as the number of transducers and channels dramatically increases, new challenges concerning the integration of electronics and the implementation of smart micro-beamforming strategies arise. Hence, the possibility to predict the behavior of the whole system is mandatory.
a b s t r a c t Fingerprint imaging using ultrasound has been investigated for several years and ... more a b s t r a c t Fingerprint imaging using ultrasound has been investigated for several years and has shown to be a valid alternative to optical scanners. Capacitive micro-machined ultrasound transducers (cMUT) is an emerging MEMS technology that can be profitably exploited in biometric applications, like fingerprint or palm print.
Two capacitive micro-fabricated ultrasonic transducers (cMUT) are evaluated for application in bi... more Two capacitive micro-fabricated ultrasonic transducers (cMUT) are evaluated for application in biometric recognition. Both transducers are 192 elements linear arrays, fabricated using the Reverse Process™ previously reported by some of the authors, and allow broadband operation at a center frequency of 12 MHz. The transducers have different pitches and acoustic lenses to allow different resolutions and focal lengths.
Proceedings of the IEEE Ultrasonics Symposium
The electrical and mechanical behavior of cMUTs is currently under investigation. The mechanical ... more 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 by means of equally spaced pillars. Each membrane layer is metallized in order to apply and detect the electrical signals. A simple analytical lumped parameters model shows that a multilayer cMUT structure can achieve higher sensitivity and maximum pressure level while mantaining broadband behavior. We report finite element modeling (FEM) of possible configurations of multilayer cMUTs for broadband immersion operation in the MHz frequency range. The results obtained show enhanced sensitivity and bandwidth performances in respect of conventional cMUTs.
2006 IEEE Ultrasonics Symposium, 2006
The electrical and mechanical behavior of cMUTs is currently under investigation. The mechanical ... more 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 by
IEEE Ultrasonics Symposium, 2004, 2004
In this work, design criteria for a low-noise, wideband front-end electronics suitable for Capaci... more In this work, design criteria for a low-noise, wideband front-end electronics suitable for Capacitive Micromachined Ultrasonic Transducers (CMUTs) pulse-echo operation are given. To investigate which configuration of the receiving amplifier assures the best performance, the basic circuits of voltage and transimpedance amplifier are both analyzed, optimized and compared through PSpice simulations. Custom electronics are also realized, based on the reported analysis, and the performances are evaluated using a fabricated 64-element CMUT array.
2014 IEEE International Ultrasonics Symposium, 2014
Fig. 1. Schematic representation of the "unimorph" elementary cell structure and operating princi... more Fig. 1. Schematic representation of the "unimorph" elementary cell structure and operating principle (a) and a particular of the proposed transducer structure (b).
2007 IEEE Ultrasonics Symposium Proceedings, 2007
Real-time 3D ultrasound imaging is based on volumetric beam steering and sweeping. Transducer cap... more 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 volumetric beamforming based on a particular two dimensional array of a reduced number of elements obtained by superimposing two linear arrays on the same area. Capacitive Micromachined Ultrasonic Transducer (cMUT) technology is mentioned as a good candidate to approach the problem due to the possibility given by micromachining to fabricate arbitrarily shaped electrode patterns which define the array elements. The beamforming strategy is illustrated and assessed by means of beampattern calculations and synthetic 3D imaging formation. The resulting array is directly connectable to a standard imaging system.
The validity of cMUT technology for medical imaging applications has been proved by many authors.... more The validity of cMUT technology for medical imaging applications has been proved by many authors. The large bandwidth obtainable with capacitive Micromachined Ultrasonic Transducers (cMUT) leads to improved image resolution if compared to their piezoelectric counterpart. However cMUTs actually show lower sensitivity than piezoelectric transducers, mainly due to their non optimized design and fabrication technology. Recently, we developed in our laboratories a dual-frequency plasma-enhanced chemical-vapour-deposition (DF-PECVD) process, improving the electrical and mechanical characteristics of the silicon nitride films that we employed to fabricate cMUTs. The DF-PECVD technique makes it possible to control, with extreme precision and over a wide range of values, the stress of the grown silicon nitride film. The result is an increased cohesion and an increased resistivity of the silicon nitride film. As a consequence, the porosity of the obtained DF-PECVD nitride film is extremely reduced thus contributing to effectively sealing the underlying cavities of the cMUT membranes. The improvement of both mechanical and electrical properties of the cMUT structural layer has led to higher transmission and reception sensitivity. Using this silicon nitride deposition technique, we have fabricated 64-elements, 5 MHz echographic probes featuring 100% bandwidth and higher sensitivity characteristics leading to a remarkable improvement in the quality of the echographic images.
ABSTRACT In this work we report on the performance optimization of a recently developed high freq... more ABSTRACT In this work we report on the performance optimization of a recently developed high frequency CMUT probe. By leveraging the advantages offered by our proprietary “Reverse Fabrication Process (RFP)” CMUT technology, we have developed an efficient and reliable packaging process, useful for the fabrication of small sized ultrasound probe-heads. We have maximized the performance by connecting the CMUT probe-head to multichannel analog front-end electronic circuits housed into the probe. An experimental comparison with an equivalent piezoelectric probe, the LA435 commercialized by Esaote S.p.A. (Italy), carried out by means of pulse-echo measurements, showed superior performance for the CMUT probe. Real time in-vivo ultrasound imaging capability demonstrates the actual usability of CMUT technology for medical imaging.
2014 IEEE International Ultrasonics Symposium, 2014
In this paper, we propose a method to improve the lateral resolution and the contrast of ultrasou... more In this paper, we propose a method to improve the lateral resolution and the contrast of ultrasound images, based on the cancellation of the sole contribution due to the sidelobes, thus maintaining the original depth of field and penetration capability. In the proposed method, each scan line is obtained by compounding the signals reconstructed by two emissions. For the first one, typical aperture and apodization profile are adopted. In the second emission, the same aperture is used, but the sign of the apodization profile is inverted over the second half of the aperture. The same approach is applied in receive. In this way, the second two-way beam has a main lobe with near-zero amplitude and sidelobes close to those of the first beam. The RF echo-signals corresponding to the two emissions are demodulated and successively subtracted. The resulting signal is finally log-compressed and scan converted. Simulations and in vivo experiments show a significant improvement of both detail and contrast resolution.
2013 IEEE International Ultrasonics Symposium (IUS), 2013
Augmented Reality (AR) is the new frontier of the human-machine interfaces. A localization system... more Augmented Reality (AR) is the new frontier of the human-machine interfaces. A localization system based on coded ultrasound capable to localize and track in real time head-mounted glasses is presented. An AR system has to know the point of view of the user with a high degree of accuracy, in order to correctly superimpose supplemental information to the scene. In past works, the authors presented different prototypes of locating systems based on airborne ultrasound, fast and accurate enough for the implementation of touch-less gestural interfaces. In this work, the development of a first prototype of a modified locating system well suited to work in conjunction with AR glasses is reported.
2010 IEEE International Ultrasonics Symposium, 2010
ABSTRACT Export Date: 29 November 2012, Source: Scopus, Art. No.: 5935620
ABSTRACT In this work an experimental evaluation of the possiblity to influence and control the f... more ABSTRACT In this work an experimental evaluation of the possiblity to influence and control the fluid film forces in the gap of a lubricated journal bearing by means of a rotating travelling wave is carried out. The travellig wave is generated by two power actuators opportunely positioned on the outer surface of the bearing and electrically driven with a phase shift of 90 degrees. Each transducer is designed to work at the natural frequency of the radial nonaxisymmetrical mode 0-5 (23.6 kHz). Experimental results show that the travelling wave is capable to control the motion of an oil drop on the inner surface of the bearing and that it is capable to put in rotation a rotor layed on the drop oil via the viscous forces in the oil drop itself.
2013 IEEE International Ultrasonics Symposium (IUS), 2013
ABSTRACT In phased array systems, a partial beamforming can be carried out inside the probe to re... more ABSTRACT In phased array systems, a partial beamforming can be carried out inside the probe to reduce the number of signals to be processed by the main system. Such technique, known as micro-beamforming, involves the application of a delay-and-sum beamforming to small groups of adjacent array elements using dedicated electronics. In this paper we show that, due to the electrostatic spring-softening effect, the phase response of Capacitive Micromachined Ultrasonic Transducers (CMUTs) can be controlled by varying the bias voltage. Based on this phenomenon, we propose a phase shift micro-beamforming method of CMUT arrays. We analyze the performance obtainable by applying this method to a typical phased array configuration for medical imaging. We show that, with relatively high quality factor CMUTs that still allow broadband immersion operation, it is possible to obtain up to 90° phase shifts by varying the bias voltage. Further, by inverting the sign of the bias voltage, we show that it is possible to obtain an additional 180° phase shift. Simulation results show that, with a 40% -3 dB one-way fractional bandwidth CMUT, the grating lobe level of the transmission radiation patterns, obtained with the proposed micro-beamforming technique, may be kept below -23 dB using broadband excitation signals for maximum steering angles of ±45°.
2010 IEEE International Ultrasonics Symposium, 2010
ABSTRACT In this work, 3D ultrasonic images of the internal region of the palm ofthe human hand a... more ABSTRACT In this work, 3D ultrasonic images of the internal region of the palm ofthe human hand are presented and analyzed in order to evaluate the ultrasonictechnique for biometric recognition purposes. A commercial ultrasound imagingmachine provided with a high frequency (12 MHz) linear array has been employed.The probe is moved in the directional orthogonal to the array and at each step aB-scan is performed and stored to form a 3D matrix. The data from the the 3Dmatrix are elaborated for achieving 3D ultrasonic palmprints. The results havebeen compared with corresponding sample obtained with conventional methods andthe advantages of the proposed technique are underlined and discussed.
2013 IEEE International Ultrasonics Symposium (IUS), 2013
In recent years, the increasing usage of tablet PCs and smartphones has made obsolete the traditi... more In recent years, the increasing usage of tablet PCs and smartphones has made obsolete the traditional keyboard and mouse as input devices, replaced by multi-touch or stylus-based input solutions that are perceived as being more user-friendly. Over the past 30 years, has been shown in literature and by patents, several solutions based on different types of interaction, from optics to acoustics. Our objective is to make surfaces, also wide, which have not been designed for use as a touch-screen, in particular with the new operating systems that widely use the intuitive features of the touch-methodology, usable. The goal of the work is to realize an autonomous stylus, at low cost, capable of generating flexural waves in any surface, which can be detected with a sensors system, also simple and low-cost, with an appropriate accuracy, in order to detect the position of the stylus, both to be used as pointer, either to be used as an input device for natural writing or drawing.
2012 IEEE International Ultrasonics Symposium, 2012
In this work, an ultrasound technique for achieving 3D palm vein patterns for biometric recogniti... more In this work, an ultrasound technique for achieving 3D palm vein patterns for biometric recognition purposes is proposed and experimentally tested. Commercial ultrasound imaging machine and linear arrays have been employed. Both imaging and power Doppler analysis have been performed to detect veins. The probe is moved in the directional orthogonal to the array by an automated scanning system and at each step a a 2D frame is captured and stored to form a 3D matrix. The data from the 3D matrix are elaborated for achieving 3D ultrasonic vein patterns. The proposed technique has been applied to acquire hand vein patterns of about a dozen of distinct volunteers, which are opportunely rendered and discussed.
In this paper we present an US system simulation tool, capable to study how system performance is... more In this paper we present an US system simulation tool, capable to study how system performance is influenced by both electronic and acoustic design parameters by joining acoustic-side models with those of the transducer and front-end electronics. The implemented tool has been entirely implemented in Matalb and includes US-field, CMUT and receiver front-end models. In particular, in this work we focus on the reception chain of components and evaluate the accuracy and correct functioning of the Matlab model compared to a real electronic architecture. Results and electric simulations confirmed that our tool efficiently joins all the implemented models and is able to correctly simulate and process the received echo signals.
In modern ultrasound imaging devices, two-dimensional probes and electronic scanning allow volume... more In modern ultrasound imaging devices, two-dimensional probes and electronic scanning allow volumetric imaging of anatomical structures. When dealing with the design of such complex 3-D ultrasound (US) systems, as the number of transducers and channels dramatically increases, new challenges concerning the integration of electronics and the implementation of smart micro-beamforming strategies arise. Hence, the possibility to predict the behavior of the whole system is mandatory.
a b s t r a c t Fingerprint imaging using ultrasound has been investigated for several years and ... more a b s t r a c t Fingerprint imaging using ultrasound has been investigated for several years and has shown to be a valid alternative to optical scanners. Capacitive micro-machined ultrasound transducers (cMUT) is an emerging MEMS technology that can be profitably exploited in biometric applications, like fingerprint or palm print.
Two capacitive micro-fabricated ultrasonic transducers (cMUT) are evaluated for application in bi... more Two capacitive micro-fabricated ultrasonic transducers (cMUT) are evaluated for application in biometric recognition. Both transducers are 192 elements linear arrays, fabricated using the Reverse Process™ previously reported by some of the authors, and allow broadband operation at a center frequency of 12 MHz. The transducers have different pitches and acoustic lenses to allow different resolutions and focal lengths.