A Novel Ultrasonic TOF Ranging System Using AlN Based PMUTs

Yihsiang Chiu; Chen Wang; Dan Gong; Nan Li; Shenglin Ma; Yufeng Jin

doi:10.3390/mi12030284

Micromachines (Mar 2021)

A Novel Ultrasonic TOF Ranging System Using AlN Based PMUTs

Yihsiang Chiu,
Chen Wang,
Dan Gong,
Nan Li,
Shenglin Ma,
Yufeng Jin

Affiliations

Yihsiang Chiu: School of Electronic and Computer Engineering Bldg. A, Peking University Shenzhen Graduate School, University Town, Xili, Nanshan, Shenzhen 518055, China
Chen Wang: School of Electronic and Computer Engineering Bldg. A, Peking University Shenzhen Graduate School, University Town, Xili, Nanshan, Shenzhen 518055, China
Dan Gong: Department of Mechanical & Electrical Engineering, School of Aeronautics and Astronautics, Xiamen University, Xiamen 361005, China
Nan Li: School of Electronic and Computer Engineering Bldg. A, Peking University Shenzhen Graduate School, University Town, Xili, Nanshan, Shenzhen 518055, China
Shenglin Ma: Department of Mechanical & Electrical Engineering, School of Aeronautics and Astronautics, Xiamen University, Xiamen 361005, China
Yufeng Jin: School of Electronic and Computer Engineering Bldg. A, Peking University Shenzhen Graduate School, University Town, Xili, Nanshan, Shenzhen 518055, China

DOI: https://doi.org/10.3390/mi12030284
Journal volume & issue: Vol. 12, no. 3
p. 284

Abstract

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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.

Published in Micromachines

ISSN: 2072-666X (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Mechanical engineering and machinery
Website: https://www.mdpi.com/journal/micromachines

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