An Integrated Front-end Circuit Board for Air-Coupled CMUT Burst-Echo Imaging

• Published in: Sensors (Basel, Switzerland) Vol. 20; no. 21; p. 6128
• Main Authors: Ye, Lei, Li, Jian, Zhang, Hui, Liang, Dongmei, Wang, Zhuochen
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 28.10.2020; MDPI
• Subjects: air-coupled CMUT; Bandwidths; Bias; burst-echo imaging; Circuit design; Design; Field programmable gate arrays; Form factors; front-end circuit; Gesture recognition; Imaging; imaging system; Letter; Micromachining; Noise levels; Printed circuit boards; Semiconductors; Signal to noise ratio; Transducers; Ultrasonic transducers; United States > US
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s20216128

To conduct burst-echo imaging with air-coupled capacitive micromachined ultrasonic transducers (CMUTs) using the same elements in transmission and reception, this work proposes a dedicated and integrated front-end circuit board design to build an imaging system. To the best of the authors’ knowledge, this is the first air-coupled CMUT burst-echo imaging using the same elements in transmission and reception. The reported front-end circuit board, controlled by field programmable gate array (FPGA), consisted of four parts: an on-board pulser, a bias-tee, a T/R switch and an amplifier. Working with our 217 kHz 16-element air-coupled CMUT array under 100 V DC bias, the front-end circuit board and imaging system could achieve 22.94 dB signal-to-noise ratio (SNR) in burst-echo imaging in air, which could represent the surface morphology and the three-dimensional form factor of the target. In addition, the burst-echo imaging range of our air-coupled CMUT imaging system, which could work between 52 and 273 mm, was discussed. This work suggests good potential for ultrasound imaging and gesture recognition applications.