Microfabricated silicon-on-Pyrex passive wireless wall shear stress sensor

TitleMicrofabricated silicon-on-Pyrex passive wireless wall shear stress sensor
Publication TypeConference Paper
Year of Publication2011
AuthorsSells, J., V. Chandrasekharan, J. Meloy, M. Sheplak, H. Zmuda, and D. P. Arnold
Conference Name2011 IEEE Sensors2011 IEEE SENSORS Proceedings
Conference LocationLimerick, Ireland
ISBN Number978-1-4244-9288-6

This paper presents the design, fabrication, and characterization of a passive wireless sensor for the measurement of wall shear stress. A micromachined variable-capacitor shear stress transducer is realized using a silicon-on-Pyrex microfabrication process. The design features a diamond-shaped 2.25 mm2 silicon floating-element to accommodate more comb fingers for improved capacitive transduction in a smaller die area. The variable-capacitor device is connected to a fixed inductor on a printed circuit board to enable passive wireless sensing. The nominal resonant frequency of the device is 168 MHz with a quality factor of 8.6. Calibrations of static shear stress in a flow cell show a linear response to over 4 Pa, with a frequency-shift sensitivity of 474 kHz/Pa (1.1% full scale). Theoretically a minimum detectable shear stress of 4.1 mPa can be resolved giving a 61.7 dB dynamic range.

Refereed DesignationRefereed