High-Accuracy Ultrasonic Rangefinders via pMUTs Arrays Using Multi-Frequency Continuous Waves

Chen, Xuying; Xu, Jinghui; Chen, Hong; Ding, Hong; Xie, Jin

doi:10.1109/jmems.2019.2912869

Cited by 47 publications

(41 citation statements)

References 31 publications

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“…For the same TOF method in [ 14 ], the range and accuracy of this work both have been improved due to the usage of more advanced fabrication process and customized circuits. Compared with the phase-shift method [ 23 ], the TOF method has a larger sensing range, but the accuracy is slightly lower, especially at short distances (e.g., <100 mm), while the phase shift method has extremely high accuracy.…”

Section: System Evaluationmentioning

confidence: 99%

A Novel Ultrasonic TOF Ranging System Using AlN Based PMUTs

et al. 2021

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This paper presents a high-accuracy complementary metal oxide semiconductor (CMOS) driven ultrasonic ranging system based on air coupled aluminum nitride (AlN) based piezoelectric micromachined ultrasonic transducers (PMUTs) using time of flight (TOF). The mode shape and the time-frequency characteristics of PMUTs are simulated and analyzed. Two pieces of PMUTs with a frequency of 97 kHz and 96 kHz are applied. One is used to transmit and the other is used to receive ultrasonic waves. The Time to Digital Converter circuit (TDC), correlating the clock frequency with sound velocity, is utilized for range finding via TOF calculated from the system clock cycle. An application specific integrated circuit (ASIC) chip is designed and fabricated on a 0.18 μm CMOS process to acquire data from the PMUT. Compared to state of the art, the developed ranging system features a wide range and high accuracy, which allows to measure the range of 50 cm with an average error of 0.63 mm. AlN based PMUT is a promising candidate for an integrated portable ranging system.

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Section: System Evaluationmentioning

confidence: 99%

A Novel Ultrasonic TOF Ranging System Using AlN Based PMUTs

et al. 2021

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“…that operate via the through thickness or radial resonant mode of a piezoelectric disc, a significant limitation is the mismatch of acoustic impedance between the transducer and gas, which can be improved to some extent by attaching an acoustic matching layer to the piezoelectric ceramic disc [13]. Micromachining techniques have been introduced to develop MEMS-based array transducers achieving good control of the acoustic radiation patterns [14,15], with relatively high intensity such as Capacitive Micromachined Ultrasonic Transducers (CMUTs) [15]. Active films exhibiting low acoustic impedance, such as polyvinylidene fluoride (PVDF) piezoelectric film, scandium-doped aluminium nitride (ScAlN) film and electromechanical film (EMFi), have also been adopted for ultrasonic transducers in order to achieve better acoustic coupling between the transducer and air [16,17].…”

Section: Introductionmentioning

confidence: 99%

The High Frequency Flexural Ultrasonic Transducer for Transmitting and Receiving Ultrasound in Air

2020

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“…As a matter of fact, it increases the mass term and, consequently, it affects the stiffness. The phenomenon is due to its proportionality to the accelerations, by means of the acoustic-structural coupling condition [18] ∂p ac ∂z = −ρ fẅ (4) where ρ f is the fluid mass density.…”

Section: Results and Experimental Validationmentioning

confidence: 99%

“…Piezoelectric Micromachined Ultrasonic Transducers (PMUTs) are layered diaphragms with a piezoelectric layer for emitting and receiving ultrasonic waves [1,2]. Nowadays, they are employed in several applications: in-air propagation is exploited for gesture recognition and range-finding [3,4,5]; in-water propagation is used for micropumps [6,7], sonography [8] and finger-printing recognition [9]. This work is focused on an air-coupled array of 4x4 circular transducers ( Fig.…”

Section: Introductionmentioning

confidence: 99%