scholarly journals Development of a 2-D Array Ultrasonic Transducer for 3-D Imaging of Objects Immersed in Water

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3501
Author(s):  
Estevão Patricio Rodrigues ◽  
Timoteo Francisco de Oliveira ◽  
Marcelo Yassunori Matuda ◽  
Flávio Buiochi
Keyword(s):  
Angular Resolution ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Data Sets ◽  
Negative Pulse ◽  
Central Frequency ◽  
Array Transducer ◽  
Half Wavelength ◽  
Volume Of Interest ◽  
Center Distance

Most works that address 2-D array ultrasonic transducers for underwater applications are about the geometry aspects of the array and beamforming techniques to make 3-D images. They look for techniques to reduce the number of elements from wide apertures, maintaining the side lobes and the grating lobes at acceptable levels, but not many details about the materials and fabrication processes are described. To overcome these gaps, this paper presents in detail the development of a 2-D array ultrasonic transducer prototype that can individually emit and receive ultrasonic pulses to make 3-D images of immersed reflectors within a volume of interest (VOI). It consists of a 4 × 4 matrix ultrasonic transducer with a central frequency of 480 kHz. Each element is a 5 mm sided square cut into a 1–3 piezocomposite. The center-to-center distance of two contiguous elements (pitch) was chosen to be greater than half wavelength, to increase the amplitude of emission and reception of signals with larger elements. Artifacts generated by grating lobes were avoided by restricting the field of view in the azimuth and elevation directions within 40° × 40° and applying the sign coherence factor (SCF) filter. Two types of backing layer materials were tested, one with air and another made of epoxy resin, on the transducers called T1 and T2, respectively. The pulse echoes measured with T1 had 2.6 dB higher amplitude than those measured with T2, and the bandwidths were 54% and 50% @ −6 dB, respectively, exciting the element with a single rectangular negative pulse. The 3-D images obtained with full matrix capture (FMC) data sets acquired of objects from 0.2 to 1.15 m motivate the development of a 2-D array transducer with more elements, to increase the angular resolution and the range.

scholarly journals Development of Broadband High-Frequency Piezoelectric Micromachined Ultrasonic Transducer Array

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1823
Author(s):  
Xu-Bo Wang ◽  
Le-Ming He ◽  
You-Cao Ma ◽  
Wen-Juan Liu ◽  
Wei-Jiang Xu ◽  
...  
Keyword(s):  
High Frequency ◽  
3D Imaging ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Frequency Bandwidth ◽  
Half Wavelength ◽  
Acoustic Beams ◽  
Working Frequency ◽  
Sub Wavelength ◽  
2D Array

Piezoelectric micromachined ultrasonic transducers (PMUT) are promising elements to fabricate a two-dimensional (2D) array with a pitch small enough (approximately half wavelength) to form and receive arbitrary acoustic beams for medical imaging. However, PMUT arrays have so far failed to combine the wide, high-frequency bandwidth needed to achieve a high axial resolution. In this paper, a polydimethylsiloxane (PDMS) backing structure is introduced into the PMUTs to improve the device bandwidth while keeping a sub-wavelength (λ) pitch. We implement this backing on a 16 × 8 array with 75 µm pitch (3λ/4) with a 15 MHz working frequency. Adding the backing nearly doubles the bandwidth to 92% (−6 dB) and has little influence on the impulse response sensitivity. By widening the transducer bandwidth, this backing may enable using PMUT ultrasonic arrays for high-resolution 3D imaging.

scholarly journals A System in Package Based on a Piezoelectric Micromachined Ultrasonic Transducer Matrix for Ranging Applications

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2590
Author(s):  
Alexandre Robichaud ◽  
Dominic Deslandes ◽  
Paul-Vahé Cicek ◽  
Frederic Nabki
Keyword(s):  
High Voltage ◽  
Integrated Circuit ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Transimpedance Amplifier ◽  
Measurement Results ◽  
Ultrasonic Ranging ◽  
High Voltage Pulser ◽  
Working Frequency ◽  
Simulation Results

This paper proposes a system in package (SiP) for ultrasonic ranging composed of a 4 × 8 matrix of piezoelectric micromachined ultrasonic transducers (PMUT) and an interface integrated circuit (IC). The PMUT matrix is fabricated using the PiezoMUMPS process and the IC is implemented in the AMS 0.35 µm technology. Simulation results for the PMUT are compared to the measurement results, and an equivalent circuit has been derived to allow a better approximation of the load of the PMUT on the IC. The control circuit is composed of a high-voltage pulser to drive the PMUT for transmission and of a transimpedance amplifier to amplify the received echo. The working frequency of the system is 1.5 MHz.

Manage the Risk of Turbine Rotor Failure

2010 ◽  
Author(s):  
David Yates ◽  
Angelo Tarantino ◽  
Joop Kraijesteijn
Keyword(s):  
Ultrasonic Transducer ◽  
Large Body ◽  
The United States ◽  
Turbine Rotor ◽  
Operational Reliability ◽  
Ultrasonic Transducers ◽  
Economic Costs ◽  
Utility Industry ◽  
Power Generation Equipment ◽  
Accepted Practice

Turbine rotors failure has resulted in a broad spectrum of events ranging from catastrophic burst to prolonged forced outages that ultimately have significant economic costs for affected utilities. Avoiding turbine rotor failure and its associated cost requires a detailed understanding of the operational reliability of power generation equipment. Nearly all large body turbine and generator rotors manufactured in the United States typically have a central bore hole that provides suitable access from which to conduct various material inspections. The term “boresonics” has become synonymous with the procedure for performing ultrasonic examination of turbine rotor material as conducted from the surface of a central bore cavity. Boresonics is now a fairly common and accepted practice throughout the utility industry. In general, boresonics involves passing ultrasonic transducers through the rotor bore to search a given volume of material for flaws at different locations and orientations within a rotor forging. Each individual ultrasonic transducer has specific inherent performance characteristics based on known wave physics that governs the art of ultrasonic testing. The results of boresonic inspections offer utility engineers a basis for making intelligent decisions on the condition of turbine and generator rotors. This paper describes how boresonic inspections are typically performed in the industry. Furthermore, the paper will give a description of the equipment and required skills of the system operators and will present examples of findings based on KEMA’s experience in this field.

Method for Modeling Ultrasonic Driving Circuit and Designing Matching Network

2012 ◽  
Vol 629 ◽  
pp. 682-687 ◽  
Author(s):  
Bo Xiong Wang ◽  
Wen Feng Liu ◽  
Jian Nan Liu ◽  
Yuan Yuan Cui ◽  
Xiu Zhia Luo
Keyword(s):  
Time Domain ◽  
Power Supply ◽  
Ultrasonic Testing ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Matching Network ◽  
Matching Networks ◽  
Impedance Characteristics ◽  
Driving Circuit ◽  
Attenuation Characteristics

The performances of ultrasonic testing systems are greatly affected by the impedance characteristics of ultrasonic transducers. Conventional methods for designing matching networks consider only the characteristics of matching elements and transducer, while ignoring the effects of other elements of emission circuit. As a consequence, such method cannot give out satisfactory results. In this paper, a modeling method for ultrasonic driving circuits is proposed, which takes into account the power supply, the transformer, the matching networks, as well as the ultrasonic transducer. This method focuses on the performances both in time domain and in frequency domain. A computer simulation and experiments show that this method can provide better attenuation characteristics and energy transmission, and can be widely used for analyzing and designing matching network for ultrasonic testing systems.

Sub-array equalization technique for the parametric array loudspeaker to reduce nonlinear distortion

2021 ◽  
Vol 263 (5) ◽  
pp. 1497-1504
Author(s):  
Chi Zhang ◽  
Jing Ren ◽  
Chuang Shi
Keyword(s):  
Nonlinear Distortion ◽  
Ultrasonic Transducer ◽  
Previous Method ◽  
Ultrasonic Transducers ◽  
Acoustic Effect ◽  
The Past ◽  
Comparison Results ◽  
Equalization Technique ◽  
Nonlinear Acoustic ◽  
Parametric Array

The parametric array loudspeaker (PAL) is a directional loudspeaker which uses the nonlinear acoustic effect, namely the parametric array, to produce an audio beam from narrow ultrasonic beams. The PAL can efficiently deliver audible information, without generating noise to the surroundings. One significant drawback of the PAL is the nonlinear distortion. Therefore, many sophisticated methods have been proposed to preprocess the input signal of the PAL. However, those methods usually request a flat frequency response of the ultrasonic transducer array (UTA). In the past, equalization has been tried out for the whole UTA, but the performance was sometimes not satisfactory due to the inconsistent productions of ultrasonic transducers. This paper proposes to group the ultrasonic transducers by their impedances. Several sub-arrays are thereafter formed and equalized individually. The comparison results demonstrate that the propose sub-array equalization technique can suppress the nonlinear distortion of the PAL more effectively than the previous method.

scholarly journals The limb-brightened jet of M87 down to the 7 Schwarzschild radii scale

2018 ◽  
Vol 616 ◽  
pp. A188 ◽  
Author(s):  
J.-Y. Kim ◽  
T. P. Krichbaum ◽  
R.-S. Lu ◽  
E. Ros ◽  
U. Bach ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Angular Resolution ◽  
Magnetic Energy ◽  
Large Mass ◽  
High Angular Resolution ◽  
Data Sets ◽  
Jet Formation ◽  
Physical Conditions ◽  
Self Similar ◽  
Jet Structure

Messier 87 (M 87) is one of the nearest radio galaxies with a prominent jet extending from sub-pc to kpc scales. Because of its proximity and the large mass of its central black hole (BH), it is one of the best radio sources for the study of jet formation. We study the physical conditions near the jet base at projected separations from the BH of ~7–100 Schwarzschild radii (Rsch). Global mm-VLBI Array (GMVA) observations at 86 GHz (λ = 3.5 mm) provide an angular resolution of ~50 μas, which corresponds to a spatial resolution of only 7 Rsch and reach the small spatial scale. We use five GMVA data sets of M 87 obtained from 2004 to 2015 and present new high angular resolution VLBI maps at 86 GHz. In particular, we focus on the analysis of the brightness temperature, the jet ridge lines, and the ratio of jet to counter-jet. The imaging reveals a parabolically expanding limb-brightened jet which emanates from a resolved VLBI core of ~(8–13) Rsch in size. The observed brightness temperature of the core at any epoch is ~(1–3) × 1010 K, which is below the equipartition brightness temperature and suggests magnetic energy dominance at the jet base. We estimate the diameter of the jet at its base to be ~5 Rsch assuming a self-similar jet structure. This suggests that the sheath of the jet may be anchored in the very inner portion of the accretion disk. The image stacking reveals faint emission at the center of the edge-brightened jet on sub-pc scales. We discuss its physical implication within the context of the spine-sheath structure of the jet.

scholarly journals Designing the ultrasonic system used in industrial air filtration based on the ultrasonic cavitation phenomenon

2019 ◽  
Vol 290 ◽  
pp. 11009
Author(s):  
Dan Niţoi ◽  
Zoia Apostolescu ◽  
Constantin Petriceanu ◽  
Corneliu Rontescu
Keyword(s):  
Ultrasonic Transducer ◽  
Ultrasonic Cavitation ◽  
Ultrasonic Transducers ◽  
Air Purification ◽  
Acoustic System ◽  
Purification Process ◽  
Air Filtration ◽  
Air Filter ◽  
Cavitation Phenomenon ◽  
Working Method

The paper presents the activity developed developed in the field of polluted air purification from industrial shop (paint shops, foundries, welding constructions, forging, etc.). The advantages of using ultrasounds in the pollutant air filtration and purification process and an ultrasonic filter designed are presented considering the ultrasonic cavitation phenomenon. The main computational and construction elements of the ultra-acoustic system used in the design of the air filter are presented in the paper. The work focuses in the design of the main part of the ultrasonic system represented by ultrasonic transducer. In this case, the transducer network that is used in ultrasonic cavitation method consists of ten ultrasonic transducers. Each one of them consists of asymmetrical passive elements (reflector and radiant element).The design steps and the use of FEM as working method will provide the theoretical basis of the operation of the ultrasonic system so that it allows air filtration based on the ultrasonic acoustic cavitation phenomenon.

scholarly journals AlN-on-Si Square Diaphragm Piezoelectric Micromachined Ultrasonic Transducer with Extended Range of Detection

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 913 ◽  
Author(s):  
Suresh Alasatri ◽  
Libor Rufer ◽  
Joshua En-Yuan Lee
Keyword(s):  
Printed Circuit Board ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Circuit Board ◽  
Detection Range ◽  
Range Finding ◽  
Sensing Applications ◽  
Current State ◽  
Wire Bonds ◽  
Extended Range

We present aluminum nitride (AlN) on silicon (Si) CMOS-compatible piezoelectric micromachined ultrasonic transducers (pMUTs) with an extended detection range of up to 140 cm for touchless sensing applications. The reported performance surpasses the current state-of-art for AlN-based pMUTs in terms of the maximum range of detection using just a pair of pMUTs (as opposed to an array of pMUTs). The extended range of detection has been realized by using a larger diaphragm allowed by fabricating a thicker diaphragm than most other pMUTs reported to date. Using a pair of pMUTs, we experimentally demonstrate the capability of range-finding by correlating the time-of-flight (TOF) between the transmit (TX) and receive (RX) pulse. The results were obtained using an experimental setup where the MEMS chip was interconnected with a customized printed circuit board (PCB) using Al wire bonds.

scholarly journals Analysis of Linear Non-Destructive Testing and Evaluation Methods for Thin-Walled Structure Inspection Using Ultrasonic Array

Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 146
Author(s):  
Yang Li ◽  
Zhenggan Zhou ◽  
Jun Wang
Keyword(s):  
Signal To Noise Ratio ◽  
Near Field ◽  
Central Frequency ◽  
Destructive Testing ◽  
Array Transducer ◽  
Imaging Results ◽  
Ultrasonic Array ◽  
Thin Walled ◽  
Aluminum Plates ◽  
Non Destructive

The ultrasonic array used for thin-walled structure non-destructive inspection usually has a high central frequency so that the thickness-to-acoustic wavelength ratio is greater than 10. When the ratio is much smaller than 10, the reliability of the conventional ultrasonic array method will dramatically decrease due to the influence of the acoustic near-field. This situation is unavoidable since the available central frequency of the array transducer cannot be an arbitrarily large value. To optimize the inspection performance in this case, the testing of an ultrasonic array and the evaluation of a structure whose thickness is smaller than five-times the longitudinal wavelength are analyzed in this paper. Linear ultrasonic array methods using different combinations of wave patterns, reflection times, and coupling conditions are uniformly expressed as full matrix algorithms. Simulated and experimental full matrices of 6 mm-thick aluminum plates using a 5-MHz array transducer are captured to analyze their imaging performances and sizing abilities with respect to various defects. Analyses show that the inspection results of the wedge coupling method have a much higher signal-to-noise ratio (SNR) than the results of conventional direct contact methods. Circular defects and rectangular defects can be distinguished by comparing the imaging results of different modes. For the simulated circular defect, the diameter can be measured according to the maximum image amplitude of the defect. To simulate a rectangular defect located in the lower half of the region, the nominal length can be measured using a linear function whose input is a −6 dB drop in length of the SS-S mode image. For a real sample, the material anisotropy and complex self-reflections will decrease the SNR by about 10 dB.

scholarly journals Advances in Capacitive Micromachined Ultrasonic Transducers

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 152 ◽  
Author(s):  
Kevin Brenner ◽  
Arif Ergun ◽  
Kamyar Firouzi ◽  
Morten Rasmussen ◽  
Quintin Stedman ◽  
...  
Keyword(s):  
Review Paper ◽  
Rapid Development ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Imaging Systems ◽  
Future Trends ◽  
Levels Of Abstraction ◽  
Commercial Success ◽  
Capacitive Micromachined Ultrasonic Transducers ◽  
Capacitive Micromachined Ultrasonic Transducer

Capacitive micromachined ultrasonic transducer (CMUT) technology has enjoyed rapid development in the last decade. Advancements both in fabrication and integration, coupled with improved modelling, has enabled CMUTs to make their way into mainstream ultrasound imaging systems and find commercial success. In this review paper, we touch upon recent advancements in CMUT technology at all levels of abstraction; modeling, fabrication, integration, and applications. Regarding applications, we discuss future trends for CMUTs and their impact within the broad field of biomedical imaging.

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