Flexible Strain Sensor Based on Ultra-Thin Quartz Plate
Bin Feng, Hao Jin, Zijing Fang, Zhentao Yu, Shurong Dong, Jikui Luo
Abstract
In the past few years, many types of surface acoustic wave (SAW) strain sensors have been developed using various piezoelectric substrates to improve detectable range and sensitivity. In this paper, we report a SAW flexible strain sensor based on ultra-thin AT-X quartz plate with a thickness of 31 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu {\mathrm {m}}$ </tex-math></inline-formula> . The sensor has a high sensitivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$251.9 \mathrm{~Hz} / \mu \varepsilon$ </tex-math></inline-formula> , an excellent linearity for the strain range from 1 to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5000~\mu \varepsilon$ </tex-math></inline-formula> , and which is about 12 times higher than those of other SAW strain sensors based on bulk substrates. The resolution of the sensors is about 3280 Hz in frequency and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$14~\mu \varepsilon$ </tex-math></inline-formula> in strain. Moreover, the sensors exhibit a very low temperature coefficient of frequency (TCF) of about −1.06 ppm/°C in the temperature range from 20 to 80°C. Our new sensor paves the way for the fabrication of high-performance strain sensing devices.