Artykuły w czasopismach: „MEMS Piezoelectric Acoustic Transducers”

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XIAOMING, WU, YANG YI, ZHU YI PING, ZHANG NIN XING, REN TIANLING i LIU LITIAN. "MEMS PIEZOELECTRIC ACOUSTIC TRANSDUCER". Integrated Ferroelectrics 89, nr 1 (18.04.2007): 150–59. http://dx.doi.org/10.1080/10584580601077716.

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Chen, Shih-Jui, Youngki Choe, Lukas Baumgartel, Anderson Lin i Eun Sok Kim. "Edge-released, piezoelectric MEMS acoustic transducers in array configuration". Journal of Micromechanics and Microengineering 22, nr 2 (13.01.2012): 025005. http://dx.doi.org/10.1088/0960-1317/22/2/025005.

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Mina, Ioanna, Hyunsoo Kim, Insoo Kim, Sung Park, Kyusun Choi, Thomas Jackson, Richard Tutwiler i Susan Trolier-McKinstry. "High frequency piezoelectric MEMS ultrasound transducers". IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 54, nr 12 (grudzień 2007): 2422–30. http://dx.doi.org/10.1109/tuffc.2007.555.

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Sun, Cuimin, Menghua Zhang, Guangyong Huang, Ping Zhang, Ronghui Lin, Xiangjun Wang i Hui You. "A Microfluidic System of Gene Transfer by Ultrasound". Micromachines 13, nr 7 (16.07.2022): 1126. http://dx.doi.org/10.3390/mi13071126.

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Ultrasonic gene transfer has advantages beyond other cell transfer techniques because ultrasound does not directly act on cells, but rather pushes the gene fragments around the cells into cells through an acoustic hole effect. Most examples reported were carried out in macro volumes with conventional ultrasonic equipment. In the present study, a MEMS focused ultrasonic transducer based on piezoelectric thin film with flexible substrate was integrated with microchannels to form a microfluidic system of gene transfer. The core part of the system is a bowl-shaped curved piezoelectric film structure that functions to focus ultrasonic waves automatically. Therefore, the low input voltage and power can obtain the sound pressure exceeding the cavitation threshold in the local area of the microchannel in order to reduce the damage to cells. The feasibility of the system is demonstrated by finite element simulation and an integrated system of MEMS ultrasonic devices and microchannels are developed to successfully carry out the ultrasonic gene transfection experiments for HeLa cells. The results show that having more ultrasonic transducers leads a higher transfection rate. The system is of great significance to the development of single-cell biochip platforms for early cancer diagnosis and assessment of cancer treatment.

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Nastro, Alessandro, Marco Ferrari, Libor Rufer, Skandar Basrour i Vittorio Ferrari. "Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency". Micromachines 13, nr 1 (8.01.2022): 96. http://dx.doi.org/10.3390/mi13010096.

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The paper presents a technique to obtain an electrically-tunable matching between the series and parallel resonant frequencies of a piezoelectric MEMS acoustic transducer to increase the effectiveness of acoustic emission/detection in voltage-mode driving and sensing. The piezoelectric MEMS transducer has been fabricated using the PiezoMUMPs technology, and it operates in a plate flexural mode exploiting a 6 mm × 6 mm doped silicon diaphragm with an aluminum nitride (AlN) piezoelectric layer deposited on top. The piezoelectric layer can be actuated by means of electrodes placed at the edges of the diaphragm above the AlN film. By applying an adjustable bias voltage Vb between two properly-connected electrodes and the doped silicon, the d31 mode in the AlN film has been exploited to electrically induce a planar static compressive or tensile stress in the diaphragm, depending on the sign of Vb, thus shifting its resonant frequency. The working principle has been first validated through an eigenfrequency analysis with an electrically induced prestress by means of 3D finite element modelling in COMSOL Multiphysics®. The first flexural mode of the unstressed diaphragm results at around 5.1 kHz. Then, the piezoelectric MEMS transducer has been experimentally tested in both receiver and transmitter modes. Experimental results have shown that the resonance can be electrically tuned in the range Vb = ±8 V with estimated tuning sensitivities of 8.7 ± 0.5 Hz/V and 7.8 ± 0.9 Hz/V in transmitter and receiver modes, respectively. A matching of the series and parallel resonant frequencies has been experimentally demonstrated in voltage-mode driving and sensing by applying Vb = 0 in transmission and Vb = −1.9 V in receiving, respectively, thereby obtaining the optimal acoustic emission and detection effectiveness at the same operating frequency.

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Chang, Shun Hsyung, Fu Tai Wang, Jiing Kae Wu, Sergey N. Shevtsov, Igor V. Zhilyaev i Maria S. Shevtsova. "The Multiobjective Design Optimization of pMUT Hydrophone". Applied Mechanics and Materials 727-728 (styczeń 2015): 660–65. http://dx.doi.org/10.4028/www.scientific.net/amm.727-728.660.

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The paper presents some results of multi-objective optimization for the multilayered membrane-type piezoceramic MEMS based transducers with perforated active PZT and intermediate diaphragms, covered by the protective plates, and a vacuum chamber. An influence of the protective plate elastic and viscous properties, the dimensions and the relative areas of the perforated holes on the sensitivity’s frequency response of the hydrophone was studied for the broadening and equalizes the operating frequency band. We optimize the key design’s parameters using the Pareto approach with the finite element (FE) model of coupled piezoelectric-acoustic problem for the hydrophone.

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Zhou, Yongxin, Yuandong Gu i Songsong Zhang. "Nondestructive Wafer Level MEMS Piezoelectric Device Thickness Detection". Micromachines 13, nr 11 (5.11.2022): 1916. http://dx.doi.org/10.3390/mi13111916.

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This paper introduces a novel nondestructive wafer scale thin film thickness measurement method by detecting the reflected picosecond ultrasonic wave transmitting between different interfacial layers. Unlike other traditional approaches used for thickness inspection, this method is highly efficient in wafer scale, and even works for opaque material. As a demonstration, we took scandium doped aluminum nitride (AlScN) thin film and related piezoelectric stacking layers (e.g. Molybedenum/AlScN/Molybdenum) as the case study to explain the advantages of this approach. In our experiments, a laser with a wavelength of 515 nm was used to first measure the thickness of (1) a single Molybdenum (Mo) electrode layer in the range of 100–300 nm, and (2) a single AlScN piezoelectric layer in the range of 600–1000 nm. Then, (3) the combined stacking layers were measured. Finally, (4) the thickness of a standard piezoelectric composite structure (Mo/AlScN/Mo) was characterized based on the conclusions and derivation extracted from the aforementioned sets of experiments. This type of standard piezoelectric composite has been widely adopted in a variety of Micro-electromechanical systems (MEMS) devices such as the Piezoelectric Micromachined Ultrasonic Transducer (PMUT), the Film Bulk Acoustic Resonator (FBAR), the Surface Acoustic Wave (SAW) and more. A comparison between measurement data from both in-line and off-line (using Scanning Electron Microscope) methods was conducted. The result from such in situ 8-inch wafer scale measurements was in a good agreement with the SEM data.

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Abdalla, Omer M. O., Gianluca Massimino, Fabio Quaglia, Marco Passoni i Alberto Corigliano. "PMUTs Arrays for Structural Health Monitoring of Bolted-Joints". Micromachines 14, nr 2 (25.01.2023): 311. http://dx.doi.org/10.3390/mi14020311.

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Micro-electro-mechanical systems (MEMS) have enabled new techniques for the miniaturization of sensors suitable for Structural Health Monitoring (SHM) applications. In this study, MEMS-based sensors, specifically Piezoelectric Micromachined Ultrasonic Transducers (PMUT), are used to evaluate and monitor the pre-tensioning of a bolted joint structural system. For bolted joints to function properly, it is essential to maintain a suitable level of pre-tensioning. In this work, an array of PMUTs attached to the head and to the end of a bolt, serve as transmitter and receiver, respectively, in a pitch-catch Ultrasonic Testing (UT) scenario. The primary objective is to detect the Change in Time of Flight (CTOF) of the acoustic wave generated by the PMUT array and propagating along the bolt’s axis between a non-loaded bolt and a bolt in service. To model the pre-tensioning of bolted joints and the transmission of the acoustic wave to and from a group of PMUTs through the bolt, a set of numerical models is created. The CTOF is found to be linearly related to the amount of pre-tensioning. The numerical model is validated through comparisons with the results of a preliminary experimental campaign.

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Reid, Andrew. "Unnatural hearing—3D printing functional polymers as a path to bio-inspired microphone design". Journal of the Acoustical Society of America 153, nr 3_supplement (1.03.2023): A195. http://dx.doi.org/10.1121/10.0018636.

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In nature, auditory organs are rarely passive transducers of their environment. Highly localized material properties and complex interdependencies mechanically filter the acoustic signal, reducing the burden of signal processing to the nervous system. Capturing these design traits in engineered systems is important for device miniaturization and energy efficiency, but manufacturing a functional electromechanical device, like a microphone, at the microscale using biologically inspired 3D designs and highly anisotropic materials remains extremely challenging. Our research uses one-pot synthesis methods for a variety of tissue-like hydrogels, polymers, and functionalized piezoelectric composites that are compatible with vat-based photopolymerization 3D printing. These materials can be used to produce reproductions of microphone designs using functional photopolymers for the conductive, piezoelectric, elastomeric, and structural elements. Used to produce mimetic structures, for example, in a device based on the directional sensitivity of the parasitoid fly Ormia ochracea, we can reproduce O. ochracea’s sound localization capability while addressing the impracticalities in frequency, sensitivity and scale of MEMS or micromachined designs. Each of the materials used has a unique set of acoustic, electrical and mechanical properties which can be tailored by altering the synthesis process leading to a truly vast design space which we are only beginning to explore.

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Vennerod, Jakob, i Matthieu Lacolle. "Miniature optical MEMS microphone with 14dBA noise floor". Journal of the Acoustical Society of America 153, nr 3_supplement (1.03.2023): A144. http://dx.doi.org/10.1121/10.0018444.

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This paper explains the fundamental technology used to create an optical microphone transducer. In recent years, microelectromechanical system (MEMS) capacitive microphones have demonstrated improved performance. State-of-the-art capacitive MEMS microphones can achieve SNR in the order of 73 dBA (21 dBA noise floor) with overall dynamic range in the order of 101 dB. There are fundamental challenges to driving the performance of capacitive MEMS microphone technology in very small packages to new heights. Piezoelectric MEMS microphones have not demonstrated SNR performance >65 dBA. The next breakthrough in miniature microphone technology will come from optical MEMS microphone technology. 80dB SNR (14 dBA noise floor) with 132 dB dynamic range (146dB maximum sound pressure level) has been achieved in a very small package. This paper will review the fundamentals of optical acoustic transduction and describe some of the approaches to miniaturization of the technology.

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Ledesma, Eyglis, Ivan Zamora, Arantxa Uranga, Francesc Torres i Núria Barniol. "Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process". Sensors 21, nr 24 (17.12.2021): 8447. http://dx.doi.org/10.3390/s21248447.

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In this paper, guidelines for the optimization of piezoelectrical micromachined ultrasound transducers (PMUTs) monolithically integrated over a CMOS technology are developed. Higher acoustic pressure is produced by PMUTs with a thin layer of AlN piezoelectrical material and Si3N4 as a passive layer, as is studied here with finite element modeling (FEM) simulations and experimental characterization. Due to the thin layers used, parameters such as residual stress become relevant as they produce a buckled structure. It has been reported that the buckling of the membrane due to residual stress, in general, reduces the coupling factor and consequently degrades the efficiency of the acoustic pressure production. In this paper, we show that this buckling can be beneficial and that the fabricated PMUTs exhibit enhanced performance depending on the placement of the electrodes. This behavior was demonstrated experimentally and through FEM. The acoustic characterization of the fabricated PMUTs shows the enhancement of the PMUT performance as a transmitter (with 5 kPa V−1 surface pressure for a single PMUT) and as a receiver (12.5 V MPa−1) in comparison with previously reported devices using the same MEMS-on-CMOS technology as well as state-of-the-art devices.

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Zhu, Jianxiong, Xinmiao Liu, Qiongfeng Shi, Tianyiyi He, Zhongda Sun, Xinge Guo, Weixin Liu, Othman Bin Sulaiman, Bowei Dong i Chengkuo Lee. "Development Trends and Perspectives of Future Sensors and MEMS/NEMS". Micromachines 11, nr 1 (18.12.2019): 7. http://dx.doi.org/10.3390/mi11010007.

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With the fast development of the fifth-generation cellular network technology (5G), the future sensors and microelectromechanical systems (MEMS)/nanoelectromechanical systems (NEMS) are presenting a more and more critical role to provide information in our daily life. This review paper introduces the development trends and perspectives of the future sensors and MEMS/NEMS. Starting from the issues of the MEMS fabrication, we introduced typical MEMS sensors for their applications in the Internet of Things (IoTs), such as MEMS physical sensor, MEMS acoustic sensor, and MEMS gas sensor. Toward the trends in intelligence and less power consumption, MEMS components including MEMS/NEMS switch, piezoelectric micromachined ultrasonic transducer (PMUT), and MEMS energy harvesting were investigated to assist the future sensors, such as event-based or almost zero-power. Furthermore, MEMS rigid substrate toward NEMS flexible-based for flexibility and interface was discussed as another important development trend for next-generation wearable or multi-functional sensors. Around the issues about the big data and human-machine realization for human beings’ manipulation, artificial intelligence (AI) and virtual reality (VR) technologies were finally realized using sensor nodes and its wave identification as future trends for various scenarios.

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Li, Tao, Le Zhang, Wenping Geng, Jian He, Yongkang Rao, Jiabing Huo, Kunxian Yan i Xiujian Chou. "Fabrication and DC-Bias Manipulation Frequency Characteristics of AlN-Based Piezoelectric Micromachined Ultrasonic Transducer". Micromachines 14, nr 1 (14.01.2023): 210. http://dx.doi.org/10.3390/mi14010210.

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Due to their excellent capabilities to generate and sense ultrasound signals in an efficient and well-controlled way at the microscale, piezoelectric micromechanical ultrasonic transducers (PMUTs) are being widely used in specific systems, such as medical imaging, biometric identification, and acoustic wireless communication systems. The ongoing demand for high-performance and adjustable PMUTs has inspired the idea of manipulating PMUTs by voltage. Here, PMUTs based on AlN thin films protected by a SiO2 layer of 200 nm were fabricated using a standard MEMS process with a resonant frequency of 505.94 kHz, a −6 dB bandwidth (BW) of 6.59 kHz, and an electromechanical coupling coefficient of 0.97%. A modification of 4.08 kHz for the resonant frequency and a bandwidth enlargement of 60.2% could be obtained when a DC bias voltage of −30 to 30 V was applied, corresponding to a maximum resonant frequency sensitivity of 83 Hz/V, which was attributed to the stress on the surface of the piezoelectric film induced by the external DC bias. These findings provide the possibility of receiving ultrasonic signals within a wider frequency range, which will play an important role in underwater three-dimensional imaging and nondestructive testing.

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Gao, Yang, Ying Duan Chen, Shi Wei Xi, Ying Bin Zheng i Chao Zhang. "Development of the 400MHz Power Durable SAW Filter". Key Engineering Materials 483 (czerwiec 2011): 381–86. http://dx.doi.org/10.4028/www.scientific.net/kem.483.381.

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Rapid development of wireless communication system requires high frequency and high power surface acoustic wave (SAW) filter. For SAW RF MEMS devices on diamond film, they have higher working frequency and more power endurance. A SAW RF MEMS filters on diamond film is designed. Its center frequency is 400MHz, and the line width of its Inter Digital Transducer (IDT) is 5μm. The diamond film on silicon substrate is customized by the CAEP ultra-hard material Co. 2μm thick ZnO piezoelectric film is deposited on diamond film by RF sputtering method. XRD analysis shows that the ZnO film has good C-axis orientation. IDT is fabricated by lift-off process. With delicate process control, designed delicate IDT pattern is acquired. The SAW RF MEMS filter prototype is finally packaged and tested. Its measured center frequency is about 378MHz, with insertion loss of 15.99dB.

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Xiu, Xueying, Haolin Yang, Meilin Ji, Haochen Lv i Songsong Zhang. "Development of MEMS Airflow Volumetric Flow Sensing System with Single Piezoelectric Micromachined Ultrasonic Transducer (PMUT) Array". Micromachines 13, nr 11 (15.11.2022): 1979. http://dx.doi.org/10.3390/mi13111979.

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Compared to conventional ultrasonic flowmeters using multiple transducers, this paper reports, for the first time, an airflow volumetric flowmeter using a signal PMUT array to measure the flow rate in a rectangular pipe. The PMUT around 200 kHz is selected to fit the system requirements. All PMUT elements on this single array are then electrically grouped into transmitter and receiver. In order to minimize the crosstalk signal between transmitter and receiver, a phase shift signal is applied at the transmitter to reduce the amplitude of the crosstalk signal by 87.8%, hence, the resultant high sensing resolution. Based on the analog signal extracted from the single PMUT array, a complete flow sensing system is built by using the cross-correlation method and cosine interpolation, whereby the change in flow rate is reflected by the time of flight difference (dTof) recorded at the receiver. Meanwhile, the acoustic path self-calibration is realized by using multiple echoes. Compared with the previously reported MEMS flowmeters with dual or multiple PMUT devices, this paper proposes a single PMUT array flow sensing system, which is able to measure the flow rate changes up to 4 m3/h. With the implementation of a single device, the problem of ultrasound device/reflector misalignment during system setup is completely eradicated.

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Liu, Zhirong, Min Zhu, Caihua Xu, Wenqi Bao, Liqiang Xie, Haitao Zhang i Yueqi Han. "Electric field sensing characteristics of ZnO/SiO₂/Si surface acoustic wave devices". Journal of Micromechanics and Microengineering 32, nr 5 (17.03.2022): 055001. http://dx.doi.org/10.1088/1361-6439/ac5b1c.

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Abstract Existing microelectro mechanical systems (MEMSs) electric field sensors have movable parts and electronic components. The movable parts are susceptible to external vibration, and the electronic components distort the distribution of the measured electric field. Therefore, we proposed a novel MEMS electric field sensor based on surface acoustic wave (SAW) technology. The SAW electric field sensor is a delay line device with an interdigital transducer and a reflector. The substrate of the device is a ZnO/SiO2/Si multilayer structure. The ZnO piezoelectric layer is not only used as the propagation medium of SAW, but also used as the sensing film of the external electric field. Then, the external electric field could be detected by analyzing the change of the eigenfrequency of the SAW. The multilayer structure of the substrate was prepared by MEMS process. The interdigital transducer and the reflector are fabricated by the lift-off process. The SAW sensor is characterized at different external electric field strengths by a network analyzer. The sensitivity of the sensor was 0.23 kHz/(kV m−1) and the nonlinearity was 6.8%.

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Walk, Christian, Matthias Wiemann, Michael Görtz, Jens Weidenmüller, Andreas Jupe i Karsten Seidl. "A Piezoelectric Flexural Plate Wave (FPW) Bio-MEMS Sensor with Improved Molecular Mass Detection for Point-of-Care Diagnostics". Current Directions in Biomedical Engineering 5, nr 1 (1.09.2019): 265–68. http://dx.doi.org/10.1515/cdbme-2019-0067.

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AbstractA piezoelectric FPW-sensor has been developed for a point of care device in this work. The Bio- MEMS FPW-sensor consists of an electrode configuration termed as an interdigital transducer (IDT) placed on a membrane. An input IDT excites and an output IDT detects the propagating acoustic waves through a PZT layer. Design optimizations and fabrication improvements of the FPW-sensor led to significantly reduced attenuation of the wave signal and the damping of the propagating waves between the IDTs. The working principle of mass loading is shown using different low-viscous liquids. A densitydependent sensitivity of -0.39 MHz/g/cm³ was evaluated. After the membrane was functionalized, the Bio-MEMS FPW-sensor was used to measure a specific chemokine in complex solution. By design improvements, the resolution was significantly increased from 0.7 Hz/nM to 14 Hz/nM.

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Zhi, Baoyu, Zhipeng Wu, Caihui Chen, Minkan Chen, Xiaoxia Ding i Liang Lou. "A High Sensitivity AlN-Based MEMS Hydrophone for Pipeline Leak Monitoring". Micromachines 14, nr 3 (14.03.2023): 654. http://dx.doi.org/10.3390/mi14030654.

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In this work, a miniaturized, low-cost, low-power and high-sensitivity AlN-based micro-electro-mechanical system (MEMS) hydrophone is proposed for monitoring water pipeline leaks. The proposed MEMS Hydrophone consists of a piezoelectric micromachined ultrasonic transducer (PMUT) array, an acoustic matching layer and a pre-amplifier amplifier circuit. The array has 4 (2 × 2) PMUT elements with a first-order resonant frequency of 41.58 kHz. Due to impedance matching of the acoustic matching layer and the 40 dB gain of the pre-amplifier amplifier circuit, the packaged MEMS Hydrophone has a high sound pressure sensitivity of −170 ± 2 dB (re: 1 V/μPa). The performance with respect to detecting pipeline leaks and locating leak points is demonstrated on a 31 m stainless leaking pipeline platform. The standard deviation (STD) of the hydroacoustic signal and Monitoring Index Efficiency (MIE) are extracted as features of the pipeline leak. A random forest model is trained for accurately classifying the leak and no-leak cases using the above features, and the accuracy of the model is about 97.69%. The cross-correlation method is used to locate the leak point, and the localization relative error is about 10.84% for a small leak of 12 L/min.

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Lee, Young Sup, Hyoung Jin Im, Jaehwa Kwon i Dong Jin Yoon. "Biologically Inspired Smart Sensor for Acoustic Emission Detection". Key Engineering Materials 321-323 (październik 2006): 204–7. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.204.

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This paper presents concept, analysis and experiment of a novel sensor which is based on biologically inspired approach for acoustic emission (AE) detection. It is known that a conventional AE sensor consists of a matching layer, piezoelectric transducer, backing layer, supporting electric circuit and casing. The conventional AE sensors have been widely used to detect defects in various structures and they have designed as either broadband or resonant type. However, the novel sensor described in this paper utilizes the concept of hearing organs in animals with the help of micro electro-mechanical systems (MEMS) technology. The basic design with theoretical investigation including finite element analysis showed the core hearing element such as a hair cell could be implemented with the piezoeletric material. Also it is found that the dimensional variety and proper distribution of such elements inside the sensor are critical parameters to the detectability of AE signals from structures. Both the broadband and resonant type AE sensors with relevant electric circuits could be implemented with this novel sensor concept.

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Ji, Meilin, Haolin Yang, Yongxin Zhou, Xueying Xiu, Haochen Lv i Songsong Zhang. "Bimorph Dual-Electrode ScAlN PMUT with Two Terminal Connections". Micromachines 13, nr 12 (19.12.2022): 2260. http://dx.doi.org/10.3390/mi13122260.

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This paper presents a novel bimorph Piezoelectric Micromachined Ultrasonic Transducer (PMUT) fabricated with 8-inch standard CMOS-compatible processes. The bimorph structure consists of two layers of 20% scandium-doped aluminum nitride (Sc0.2Al0.8N) thin films, which are sandwiched among three molybdenum (Mo) layers. All three Mo layers are segmented to form the outer ring and inner plate electrodes. Both top and bottom electrodes on the outer ring are electrically linked to the center inner plate electrodes. Likewise, the top and bottom center plate electrodes are electrically connected to the outer ring in the same fashion. This electrical configuration maximizes the effective area of the given PMUT design and improves efficiency during the electromechanical coupling process. In addition, the proposed bimorph structure further simplifies the device’s electrical layout with only two-terminal connections as reported in many conventional unimorph PMUTs. The mechanical and acoustic measurements are conducted to verify the device’s performance improvement. The dynamic mechanical displacement and acoustic output under a low driving voltage (1 Vpp) are more than twice that reported from conventional unimorph devices with a similar resonant frequency. Moreover, the pulse-echo experiments indicate an improved receiving voltage of 10 mV in comparison with the unimorph counterpart (4.8 mV). The validation of device advancement in the electromechanical coupling effect by using highly doped ScAlN thin film, the realization of the proposed bimorph PMUT on an 8-inch wafer paves the path to production of next generation, high-performance piezoelectric MEMS.

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Zamora, Iván, Eyglis Ledesma, Arantxa Uranga i Núria Barniol. "Miniaturized 0.13-μm CMOS Front-End Analog for AlN PMUT Arrays". Sensors 20, nr 4 (22.02.2020): 1205. http://dx.doi.org/10.3390/s20041205.

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This paper presents an analog front-end transceiver for an ultrasound imaging system based on a high-voltage (HV) transmitter, a low-noise front-end amplifier (RX), and a complementary-metal-oxide-semiconductor, aluminum nitride, piezoelectric micromachined ultrasonic transducer (CMOS-AlN-PMUT). The system was designed using the 0.13-μm Silterra CMOS process and the MEMS-on-CMOS platform, which allowed for the implementation of an AlN PMUT on top of the CMOS-integrated circuit. The HV transmitter drives a column of six 80-μm-square PMUTs excited with 32 V in order to generate enough acoustic pressure at a 2.1-mm axial distance. On the reception side, another six 80-μm-square PMUT columns convert the received echo into an electric charge that is amplified by the receiver front-end amplifier. A comparative analysis between a voltage front-end amplifier (VA) based on capacitive integration and a charge-sensitive front-end amplifier (CSA) is presented. Electrical and acoustic experiments successfully demonstrated the functionality of the designed low-power analog front-end circuitry, which outperformed a state-of-the art front-end application-specific integrated circuit (ASIC) in terms of power consumption, noise performance, and area.

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Wang, Jhih-Jhe, Tsung-Hsing Hsu, Che-Nan Yeh, Jui-Wei Tsai i Yu-Chuan Su. "Piezoelectric polydimethylsiloxane films for MEMS transducers". Journal of Micromechanics and Microengineering 22, nr 1 (23.12.2011): 015013. http://dx.doi.org/10.1088/0960-1317/22/1/015013.

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Ozevin, D., D. W. Greve, I. J. Oppenheim i S. P. Pessiki. "Resonant capacitive MEMS acoustic emission transducers". Smart Materials and Structures 15, nr 6 (2.11.2006): 1863–71. http://dx.doi.org/10.1088/0964-1726/15/6/041.

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Jung, Soo Young, Jin Soo Park, Min-Seok Kim, Ho Won Jang, Byung Chul Lee i Seung-Hyub Baek. "Piezoelectric Ultrasound MEMS Transducers for Fingerprint Recognition". JOURNAL OF SENSOR SCIENCE AND TECHNOLOGY 31, nr 5 (30.09.2022): 286–92. http://dx.doi.org/10.46670/jsst.2022.31.5.286.

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Kabir, Minoo, Hanie Kazari i Didem Ozevin. "Piezoelectric MEMS acoustic emission sensors". Sensors and Actuators A: Physical 279 (sierpień 2018): 53–64. http://dx.doi.org/10.1016/j.sna.2018.05.044.

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Griffin, Benjamin A., Scott D. Habermehl i Peggy J. Clews. "High Temperature Microelectromechanical Systems Using Piezoelectric Aluminum Nitride". Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2014, HITEC (1.01.2014): 000040–46. http://dx.doi.org/10.4071/hitec-ta24.

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We report on the efforts at Sandia National Laboratories to develop high temperature capable microelectromechanical systems (MEMS). MEMS transducers are pervasive in today's culture, with examples found in cell phones, automobiles, gaming consoles, and televisions. There is currently a need for MEMS transducers that can operate in more harsh environments, such as automobile engines, gas turbines, nuclear and coal power plants, and petroleum and geothermal well drilling. Our development focuses on the coupling of silicon carbide (SiC) and aluminum nitride (AlN) thin films on SiC wafers to form a MEMS material set capable of temperatures beyond 1000°C. SiC is recognized as a promising material for high temperature capable MEMS transducers and electronics because it has the highest mechanical strength of semiconductors with the exception of diamond and its upper temperature limit exceeds 2500°C, where it sublimates rather than melts. Most transduction schemes in SiC are focused on measuring changes in capacitance or resistance, which require biasing or modulation schemes that can withstand elevated temperatures. Instead, we are coupling temperature hardened, micro-scale SiC mechanical components with piezoelectric AlN thin films. AlN is a non-ferroelectric piezoelectric material, enabling piezoelectric transduction at temperatures exceeding 1000°C. AlN is a favorable MEMS material due to its high thermal, electrical, and mechanical strength. It is also closely matched to SiC for coefficient of thermal expansion.

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Wu, K. T., C. K. Jen i M. Kobayashi. "Integrated piezoelectric plate acoustic waves transducers". Electronics Letters 44, nr 12 (2008): 776. http://dx.doi.org/10.1049/el:20080936.

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Bauer, F., M. Boisrayon, M. Richard i C. Massot. "Piezoelectric thick copolymer for acoustic transducers". Journal of the Acoustical Society of America 84, S1 (listopad 1988): S102. http://dx.doi.org/10.1121/1.2025644.

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Pratap, Rudra, Ajay Dangi, Kaustav Roy i Harshvardhan Gupta. "(Invited) Fluid Spectroscopy with Piezoelectric Ultrasound MEMS Transducers". ECS Transactions 86, nr 16 (23.07.2018): 13–20. http://dx.doi.org/10.1149/08616.0013ecst.

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Ahmed, Imtiaz, i Dana Weinstein. "Switchable Transducers in GaN MEMS Resonators: Performance Comparison and Analysis". Micromachines 12, nr 4 (19.04.2021): 461. http://dx.doi.org/10.3390/mi12040461.

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This work presents a comprehensive comparison of switchable electromechanical transducers in an AlN/GaN heterostructure toward the goal of reconfigurable RF building blocks in next-generation ad hoc radios. The transducers’ inherent switching was achieved by depleting a 2D electron gas (2DEG) channel, allowing an RF signal launched by interdigital transducers (IDTs) to effectively excite the symmetric (So) Lamb mode of vibration in the piezoelectric membrane. Different configurations for applying DC bias to the channel for electromechanical actuation in the piezoelectric are discussed. Complete suppression of the mechanical mode was achieved with the transducers in the OFF state. Equivalent circuit models were developed to extract parameters from measurements by fitting in both ON and OFF states. This is the first time that an extensive comparative study of the performance of different switchable transducers in their ON/OFF state is presented along with frequency scaling of the resonant mode. The switchable transducer with Ohmic IDTs and a Schottky control gate showed superior performance among the designs under consideration.

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Pyun, Joo Young, Young Hun Kim i Kwan Kyu Park. "Design of Piezoelectric Acoustic Transducers for Underwater Applications". Sensors 23, nr 4 (6.02.2023): 1821. http://dx.doi.org/10.3390/s23041821.

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Interest in underwater transducers has persisted since the mid-1900s. Underwater transducers are designed in various shapes using various materials depending on the purpose of use, such as to achieve high power, improve broadband, and enhance beam steering. Therefore, in this study, an analysis is conducted according to the structural shape of the transducer, exterior material, and active material. By classifying transducers by structure, the transducer design trends and possible design issues can be identified. Researchers have constantly attempted new methods to improve the performance of transducers. In addition, a methodology to overcome this problem is presented. Finally, this review covers old and new research, and will serve as a reference for designers of underwater transducer.

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Dauchy, F., i R. A. Dorey. "Thickness mode high frequency MEMS piezoelectric micro ultrasound transducers". Journal of Electroceramics 19, nr 4 (13.09.2007): 383–86. http://dx.doi.org/10.1007/s10832-007-9317-x.

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Li, Huidong, Z. Daniel Deng i Thomas J. Carlson. "Piezoelectric Materials Used in Underwater Acoustic Transducers". Sensor Letters 10, nr 3 (1.03.2012): 679–97. http://dx.doi.org/10.1166/sl.2012.2597.

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Ohga, Juro. "Piezoelectric acoustic transducers for electronic telephone sets". Journal of the Acoustical Society of America 84, S1 (listopad 1988): S66. http://dx.doi.org/10.1121/1.2026424.

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Niu, Xiaoyu, Yuqi Meng, Zihuan Liu, Ehsan Vatankhah i Neal A. Hall. "MEMS microphones as ultrasonic transducers". Journal of the Acoustical Society of America 152, nr 4 (październik 2022): A50—A51. http://dx.doi.org/10.1121/10.0015506.

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We demonstrate the transmission of ultrasound in air using a transducer that resembles a MEMS microphone in its construction. The device comprises a compliant 1 mm diameter diaphragm, a stiff perforated backplate electrode, and a back-volume. The diaphragm is driven using AC signals with peak values that exceed the pull-in voltage of the diaphragm. Relatively large diaphragm displacements are achieved as diaphragm oscillations traverse the complete 2.30-micrometer diaphragm-backplate gap in response to excitation waveforms spanning from 40 kHz to 150 kHz. Large amplitude diaphragm vibration is advantageous for high SPL applications in air, as sound pressure is directly proportional to diaphragm displacement for a given operating frequency. Diaphragm vibration profiles are measured using a scanning laser Doppler vibrometer, and resultant acoustic pressure waveforms in air are measured using a broadband microphone. We demonstrate how nonlinear features of the electrostatic transducer can be exploited to generate loud, broadband signals. We also discuss interesting applications using an array of these transducers.

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Šimonová, Karina, i Petr Honzík. "Modeling of MEMS Transducers with Perforated Moving Electrodes". Micromachines 14, nr 5 (24.04.2023): 921. http://dx.doi.org/10.3390/mi14050921.

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Microfabricated electroacoustic transducers with perforated moving plates used as microphones or acoustic sources have appeared in the literature in recent years. However, optimization of the parameters of such transducers for use in the audio frequency range requires high-precision theoretical modeling. The main objective of the paper is to provide such an analytical model of a miniature transducer with a moving electrode in the form of a perforated plate (rigid elastically supported or elastic clamped at all boundaries) loaded by an air gap surrounded by a small cavity. The formulation for the acoustic pressure field inside the air gap enables expression of the coupling of this field to the displacement field of the moving plate and to the incident acoustic pressure through the holes in the plate. The damping effects of the thermal and viscous boundary layers originating inside the air gap, the cavity, and the holes in the moving plate are also taken into account. The analytical results, namely, the acoustic pressure sensitivity of the transducer used as a microphone, are presented and compared to the numerical (FEM) results.

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Fa, Lin, Lianlian Kong, Hong Gong, Chuanwei Li, Lili Li, Tuo Guo, Jurong Bai i Meishan Zhao. "Numerical Simulation and Experimental Verification of Electric–Acoustic Conversion Property of Tangentially Polarized Thin Cylindrical Transducer". Micromachines 12, nr 11 (30.10.2021): 1333. http://dx.doi.org/10.3390/mi12111333.

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In solving piezoelectric equations of motion, we established an electric–acoustic equivalent circuit of tangentially polarized thin cylindrical transducers and derived analytical expressions of the electric-acoustic response from the harmonic driving-voltage excitation. To experimentally verify the findings, we manufactured a parallel electric-acoustic transmission network for transducers excited by multifrequency driving signals. We found that the tangentially polarized thin cylindrical transducers achieved a much higher electric-acoustic conversion efficiency than the radially polarized thin cylindrical transducers. The electric-acoustic impulse response of the transducers consisted of a direct-current damping with lower-frequency components, a damping oscillation with higher-frequency elements, and a higher resonant frequency of the transducer over its center frequency. The characteristics of radiated acoustic signals included contributions from the geometrical shape and size of the transducer, the physical parameters of piezoelectric material, the type of driving-voltage signals, and the polarization mode of the transducers. In comparison, our theoretical predictions are in good agreement with experimental observations. It is plausible that using the tangentially polarized thin cylindrical transducers as sensors in the acoustic-logging tool may significantly improve the signal-to-noise ratio of the measured acoustic-logging signals.

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Akhremenko, Nikolay, Yasemin Durukan, Ekaterina Popkova i Mikhail Shevelko. "THE SENSITIVITY ESTIMATION FOR THE ULTRASONIC ANGULAR VELOCITY SENSORS". Akustika, VOLUME 41 (2021): 168–72. http://dx.doi.org/10.36336/akustika202141168.

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The paper discusses the principles of the occurrence of inherent noise of the sensitive element of the angular velocity sensor, the calculation of these noises and methods of their reduction. The principle of operation of the sensing element of the angular velocity sensor on bulk acoustic waves, which consists in detecting the rotation of the polarization vector of the emitted linearly polarized shear wave, is presented in the work. The results of calculations of the noise level for various materials and sizes of plate piezoelectric transducers and acoustic duct are presented in the work. It is shown that a sensitive element with plate piezoelectric transducers made of langasite and an acoustic duct made of glass, a heavy flint, has a minimum noise level. It is shown that with an increase in the operating frequency of a plate piezoelectric transducer, the noise level decreases. A program for calculating the noise characteristics of solid-state angular velocity sensors based on bulk acoustic waves has been developed. The element base of the receiving amplifier of the device has been selected. Recommendations for reducing the level of noise are formulated, such as: increasing the operating frequency and reducing the bandwidth of plate piezoelectric transducers, as well as the choice of optimal materials for both piezoelectric transducers and acoustic duсt.

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Jiang, Runkun, Lei Mei i Q. M. Zhang. "COMSOL Multiphysics Modeling of Architected Acoustic Transducers in Oil Drilling". MRS Advances 1, nr 24 (2016): 1755–60. http://dx.doi.org/10.1557/adv.2016.46.

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ABSTRACTIn the oil and gas industry, acoustic transducers have been found to provide valuable geological sonic information such as compressional wave velocity, shear wave velocity, and rock formation slowness. These data can be used to indicate lithology, determine porosity, detect over-pressured formation zones, and check well to well correlation. One category of such acoustic transducers is equipped with piezoelectric elements. Conventional piezoelectric transducers are packaged by epoxy resin. Because of the liquid nature of uncured epoxy resin, it is difficult to position the piezoelectric elements accurately. The introduction of polyether ether ketone (PEEK) as the packaging material solved this issue. Due to the ease of machining on solid form, architectures of the composite acoustic transducers can be devised with great flexibility and creativity. These designs can be modeled with finite element methods (FEM) and the best design for the oil drilling application can be finalized and fabricated.COMSOL Multiphysics® solves problems in a programming environment that integrates relevant physics. In this case, it includes electrical circuit, solid mechanics, acoustics, and piezoelectricity. Here a compete model and procedure to study the performance of an architected composite acoustic transducer is provided. The displacement analysis gives insights into the resonance modes of the piezoelectric elements. The acoustics analysis gives the necessary information on the acoustic performance of the transducers, such as acoustic pressure spatial distribution, acoustic pressure frequency response, transmitting voltage response, and directivity. These are important criteria to judge the effectiveness of an architected transducer.

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40

Ali, Washim Reza, i Mahanth Prasad. "Piezoelectric MEMS based acoustic sensors: A review". Sensors and Actuators A: Physical 301 (styczeń 2020): 111756. http://dx.doi.org/10.1016/j.sna.2019.111756.

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Thalhammer, Gregor, Craig McDougall, Michael Peter MacDonald i Monika Ritsch-Marte. "Acoustic force mapping in a hybrid acoustic-optical micromanipulation device supporting high resolution optical imaging". Lab on a Chip 16, nr 8 (2016): 1523–32. http://dx.doi.org/10.1039/c6lc00182c.

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42

Fa, Lin, Dongning Liu, Hong Gong, Wenhui Chen, Yandong Zhang, Yimei Wang, Rui Liang i in. "A Frequency-Dependent Dynamic Electric–Mechanical Network for Thin-Wafer Piezoelectric Transducers Polarized in the Thickness Direction: Physical Model and Experimental Confirmation". Micromachines 14, nr 8 (20.08.2023): 1641. http://dx.doi.org/10.3390/mi14081641.

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This paper is concerned with electric–acoustic/acoustic–electric conversions of thin-wafer piezoelectric transducers polarized in the thickness direction. By introducing two mechanical components with frequency-dependent values, i.e., radiation resistance and radiation mass, into the equivalent circuit of the thin-wafer piezoelectric transducer, we established a frequency-dependent dynamic mechanic-electric equivalent network with four terminals for an arbitrary given frequency, an enhancement from the conventional circuit networks. We derived the analytic expressions of its electric–acoustic and acoustic–electric conversion impulse responses using the four-terminal equivalent circuit to replace the traditional six-terminal equivalent circuit for a thin-wafer transducer with harmonic vibrational motion. For multifrequency electrical/acoustic signals acting on the transducer, we established parallel electric–acoustic/acoustic–electric conversion transmission networks. These two transmission network models have simple structures and clear physical and mathematical descriptions of thin-wafer transducers for electric–acoustic/acoustic–electric conversion when excited by a multifrequency electric/acoustic signal wavelet. The calculated results showed that the transducer’s center frequency shift relates to its mechanical load and vibration state. The method reported in this paper can be applied to conventional-sized and small-sized piezoelectric transducers with universal applicability.

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Ma, Youcao, Jian Song, Yuyao Zhao, Kiyotaka Tanaka, Shijunbo Wu, Chao Dong, Xubo Wang i in. "Excellent Uniformity and Properties of Micro-Meter Thick Lead Zirconate Titanate Coatings with Rapid Thermal Annealing". Materials 16, nr 8 (18.04.2023): 3185. http://dx.doi.org/10.3390/ma16083185.

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Lead zirconate titanate (PZT) films have shown great potential in piezoelectric micro-electronic-mechanical system (piezo-MEMS) owing to their strong piezoelectric response. However, the fabrication of PZT films on wafer-level suffers with achieving excellent uniformity and properties. Here, we successfully prepared perovskite PZT films with similar epitaxial multilayered structure and crystallographic orientation on 3-inch silicon wafers, by introducing a rapid thermal annealing (RTA) process. Compared to films without RTA treatment, these films exhibit (001) crystallographic orientation at certain composition that expecting morphotropic phase boundary. Furthermore, dielectric, ferroelectric and piezoelectric properties on different positions only fluctuate within 5%. The relatively dielectric constant, loss, remnant polarization and transverse piezoelectric coefficient are 850, 0.1, 38 μC/cm2 and −10 C/m2, respectively. Both uniformity and properties have reached the requirement for the design and fabrication of piezo-MEMS devices. This broadens the design and fabrication criteria for piezo-MEMS, particularly for piezoelectric micromachined ultrasonic transducers.

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Kim, Howuk, i Xiaoning Jiang. "Numerical Study of a Miniaturized, 1–3 Piezoelectric Composite Focused Ultrasound Transducer". Applied Sciences 13, nr 1 (2.01.2023): 615. http://dx.doi.org/10.3390/app13010615.

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This study aimed to develop an optimal methodology for the design of a miniaturized, 1–3 piezoelectric composite focused ultrasound transducer. Miniaturized focused ultrasound (FUS) devices, generally guided through catheters, have received considerable attention in the biomedical and ultrasound fields as they can overcome the technical restrictions of typical FUS transducers. However, miniaturized transducers cannot readily generate a high acoustic intensity because of their small aperture sizes and the vibration mode coupling. As such, 1–3 composite transducers, having a high electromechanical coupling and efficient vibration directivity, break through the current technical restrictions. However, the systematic methodology for designing miniaturized FUS transducers has not been thoroughly discussed so far. Therefore, in this study, we designed 1–3 piezoelectric composite transducers using analytical and numerical methods. Specifically, extensive parametric studies were performed through finite element analysis under the coupled field with piezoelectricity, structural vibration, and acoustic pressure. The simulation results confirmed that the optimal design of the 1–3 composite type transducer produces much higher (>160%) acoustic pressure output at the focal point than the single-phase device. Furthermore, the array type of the interstitial transducer was predicted to produce an unprecedented acoustic intensity of approximately 188 W/cm2 under a short duty cycle (1%). This study will provide valuable technical methodology for the development of interstitial, 1–3 composite FUS transducers and the selection of optimal design parameters.

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Yang, Deng, i Jiahao Zhao. "Acoustic Wake-Up Technology for Microsystems: A Review". Micromachines 14, nr 1 (3.01.2023): 129. http://dx.doi.org/10.3390/mi14010129.

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Microsystems with capabilities of acoustic signal perception and recognition are widely used in unattended monitoring applications. In order to realize long-term and large-scale monitoring, microsystems with ultra-low power consumption are always required. Acoustic wake-up is one of the solutions to effectively reduce the power consumption of microsystems, especially for monitoring sparse events. This paper presents a review of acoustic wake-up technologies for microsystems. Acoustic sensing, acoustic recognition, and system working mode switching are the basis for constructing acoustic wake-up microsystems. First, state-of-the-art MEMS acoustic transducers suitable for acoustic wake-up microsystems are investigated, including MEMS microphones, MEMS hydrophones, and MEMS acoustic switches. Acoustic transducers with low power consumption, high sensitivity, low noise, and small size are attributes needed by the acoustic wake-up microsystem. Next, acoustic features and acoustic classification algorithms for target and event recognition are studied and summarized. More acoustic features and more computation are generally required to achieve better recognition performance while consuming more power. After that, four different system wake-up architectures are summarized. Acoustic wake-up microsystems with absolutely zero power consumption in sleep mode can be realized in the architecture of zero-power recognition and zero-power sleep. Applications of acoustic wake-up microsystems are then elaborated, which are closely related to scientific research and our daily life. Finally, challenges and future research directions of acoustic wake-up microsystems are elaborated. With breakthroughs in software and hardware technologies, acoustic wake-up microsystems can be deployed for ultra-long-term and ultra-large-scale use in various fields, and play important roles in the Internet of Things.

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Ranjan, Abhishek, Chengxiang Peng, Sanat Wagle, Frank Melandsø i Anowarul Habib. "High-Frequency Acoustic Imaging Using Adhesive-Free Polymer Transducer". Polymers 13, nr 9 (30.04.2021): 1462. http://dx.doi.org/10.3390/polym13091462.

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The piezoelectric polymer PVDF and its copolymers have a long history as transducer materials for medical and biological applications. An efficient use of these polymers can potentially both lower the production cost and offer an environment-friendly alternative for medical transducers which today is dominated by piezoelectric ceramics containing lead. The main goal of the current work has been to compare the image quality of a low-cost in-house transducers made from the copolymer P(VDF-TrFE) to a commercial PVDF transducer. Several test objects were explored with the transducers used in a scanning acoustic microscope, including a human articular cartilage sample, a coin surface, and an etched metal film with fine line structures. To evaluate the image quality, C- and B-scan images were obtained from the recorded time series, and compared in terms of resolution, SNR, point-spread function, and depth imaging capability. The investigation is believed to provide useful information about both the strengths and limitations of low-cost polymer transducers.

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WU, XIAOMING, TIANLING REN i LITIAN LIU. "ACTIVE DAMPING OF A PIEZOELECTRIC MEMS ACOUSTIC SENSOR". Integrated Ferroelectrics 80, nr 1 (listopad 2006): 317–29. http://dx.doi.org/10.1080/10584580600660108.

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Kaušinis, Saulius, i Rimantas Barauskas. "Parametric Sensitivity of MEMS-Gyro". Solid State Phenomena 113 (czerwiec 2006): 495–99. http://dx.doi.org/10.4028/www.scientific.net/ssp.113.495.

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The paper presents the finite element (FE) modeling approach to sensitivity analysis of MEMS-based gyros. The FE model is employed to both studying the system’s dynamical properties and appreciation of the sensitivity of these to various influencing effects. The sensitivity functions have been obtained for adjusting the geometric parameters of the piezoelectric transducers in order to achieve the desired values of natural frequencies. Results are presented in terms of sensor performance characteristics for various design parameters and modes of operation. The modeling assumptions adopted are tested experimentally on a cantilever-shape test vehicle.

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Griffin, Connor, i Victor Giurgiutiu. "Piezoelectric Wafer Active Sensor Transducers for Acoustic Emission Applications". Sensors 23, nr 16 (11.08.2023): 7103. http://dx.doi.org/10.3390/s23167103.

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Piezoelectric materials are defined by their ability to display a charge across their surface in response to mechanical strain, making them great for use in sensing applications. Such applications include pressure sensors, medical devices, energy harvesting and structural health monitoring (SHM). SHM describes the process of using a systematic approach to identify damage in engineering infrastructure. A method of SHM that uses piezoelectric wafers connected directly to the structure has become increasingly popular. An investigation of a novel pitch-catch method of determining instrumentation quality of piezoelectric wafer active sensors (PWASs) used in SHM was conducted as well as an investigation into the effects of defects in piezoelectric sensors and sensor bonding on the sensor response. This pitch-catch method was able to verify defect-less instrumentation quality of pristinely bonded PWASs. Additionally, the pitch-catch method was compared with the electromechanical impedance method in determining defects in piezoelectric sensor instrumentation. Using the pitch-catch method, it was found that defective instrumentation resulted in decreasing amplitude of received and transmitted signals as well as changes in the frequency spectrums of the signals, such as the elimination of high frequency peaks in those with defects in the bonding layer and an increased amplitude of around 600 kHz for a broken PWAS. The electromechanical impedance method concluded that bonding layer defects increase the primary frequency peak’s amplitude and cause a downward frequency shift in both the primary and secondary frequency peaks in the impedance spectrum, while a broken sensor has the primary peak amplitude reduced while shifting upward and nearly eliminating the secondary peak.

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Ahmad, K. A., A. Abd Manaf, Z. Hussain Hussain i Z. Janin. "Design Flexural Piezoelectric Acoustic Transducers Array based d33 Mode Polarization". Indonesian Journal of Electrical Engineering and Computer Science 10, nr 1 (1.04.2018): 59. http://dx.doi.org/10.11591/ijeecs.v10.i1.pp59-65.

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Piezoelectric Acoustic Transducer (PAT) is a transducers used in many application such as medical diagnostic, medical ultrasonic imaging and underwater acoustic applications. Latest research, PAT were investigated in marine application and underwater acoustic imaging. Conventional PAT is design based on sensing element, Piezoelectric Material, matching layer and backing layer. But the conventional method still has problem with issues of narrow bandwidth, directivity and low sensitivity. This problem is occurred when the transducer need to increase the image resolution. The size of single element will become smaller to meet the requirement of high resolution. PZT-5H have high piezoelectric constant (d31) and low dielectric loss. It is chosen as sensing element in this design of PAT because it will increase the sensitivity of transducers. The PAT is design based on d33 mode polarization to improve the receiving sensitivity. The fabrication process are included wet etching on Printed Circuit Board (PCB), spin coated Polydimethylsiloxane (PDMS), and baked transducer on hot plate. PAT is characterized using Pulse-Echo method. Pulse-Echo method will determine the sensitivity, directivity and operating bandwidth of acoustic transducers in underwater applications. Open circuit receiving voltage (OCRV) is voltage response to determine the sensitivity of acoustic transducer. The commercial projector and hydrophone will calibrate to obtain the reliability of result. In cross talk test, at some particular frequency, Pin 2 and Pin 3 have low sensitivity value. It is because Pin 2 and Pin 3 received low acoustic wave pressure. The PAT array based d33 mode polarization shows it has more receiving sensitive compared to commercial acoustic transducers. The design transducer has sensitivity at -56 dB re 1V/µPa at resonance frequency, 100kHz and fractional bandwidth at 30%.

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