High Accuracy Ultrasound Micro-Distance Measurements with PMUTs under Liquid Operation
Zamora, Iván (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Ledesma, Eyglis (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Uranga del Monte, Aránzazu (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Barniol i Beumala, Núria (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)

Date:	2021
Abstract:	Ultrasonic systems driven by multi-frequency continuous waves (MFCW) have been used for range distance measurement, offering high accuracy in long and medium range distance estimation. However, the use of continuous waves in very short-distance measurements causes large errors due to multipath reflections. This paper presents a new strategy to estimate very short relative distances with high accuracy based on the use of multi-frequency pulsed waves (MFPW). The proposed strategy allows to avoid the multipath reflections that appear when continuous waves are used, and it improves the achieved accuracy compared to the original MFCW method. To validate it, an 80 µm square AlScN piezoelectric micromachined ultrasonic transducer (PMUT) was chosen as a transmitter while a hydrophone was utilized as a target and receiver, immersed in fluorinert (FC-70) as a propagation medium. Three independent and consecutive tone-burst signals were transmitted successively. The selected frequencies are f1 = 2. 3962 MHz, f2 = 2. 327 MHz and f3 = 2. 1195 MHz, giving first and second-order resolutions of 6. 88 and 0. 79 µm/°, respectively. Experimental results show a ±6. 2 μm measured range error in a range of 3. 5 mm, and therefore it represents a good candidate for ultrasound micro-profilometer applications under liquid operation.
Grants:	Agencia Estatal de Investigación PID2019-108270RB-I00
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Immersed distance measurement ; Multi-frequency continuous waves ; Phase measurement ; PMUT ; Time-of-flight ; Ultrasound
Published in:	Sensors (Basel, Switzerland), Vol. 21, Issue 13 (July 2021) , art. 4524, ISSN 1424-8220

DOI: 10.3390/s21134524
PMID: 34282795

11 p, 2.9 MB

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Articles > Research articles
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