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Author Li, Y. ♦ Vancura, C. ♦ Hagleitner, C. ♦ Lichtenberg, J. ♦ Brand, O. ♦ Baltes, H.
Sponsorship IEEE Sensors Council
Source IEEE Xplore Digital Library
Content type Text
Publisher Institute of Electrical and Electronics Engineers, Inc. (IEEE)
File Format PDF
Copyright Year ©2003
Language English
Subject Domain (in DDC) Technology ♦ Engineering & allied operations ♦ Applied physics
Subject Keyword Q factor ♦ Resonance ♦ Liquids ♦ Biosensors ♦ Resonant frequency ♦ Feedback circuits ♦ Laser feedback ♦ Damping ♦ Feedback loop ♦ Lorentz covariance
Abstract We present a novel, monolithic, mass-sensitive cantilever sensor for measurements in liquids, which achieves a high quality factor (Q-factor) by closed-loop actuation. The cantilever is the frequency-determining element in the feedback system, its resonance frequency being a function of the mass-change on the surface. While cantilever-based sensors generally suffer from low quality factors in liquids due to the strong damping, our device uses an internal feedback loop circuitry to enhance the Q-factor. This allows to increase Q-factor from 23 to 19,000 at a resonance frequency of 221 kHz. The cantilever is electromagnetically actuated by Lorentz force while the oscillation is detected by piezoresistive MOS-transistors. A fully differential feedback circuitry with amplitude control is integrated together with the cantilever on the same chip. Thanks to the high Q-factor and the resulting frequency stability, even small frequency (and mass) changes can be precisely measured by this fully integrated system. Therefore, active, external actuation or readout instrumentation, such as a laser for optical detection, is not required. The sensor is an excellent candidate for biosensing applications in liquids such as biomolecule hybridization and illustrates the advantage of integrated circuitry for resonant sensors.
Description Author affiliation: Phys. Electron. Lab., Eidgenossische Tech. Hochschule, Zurich, Switzerland (Li, Y.; Vancura, C.; Hagleitner, C.; Lichtenberg, J.; Brand, O.; Baltes, H.)
ISBN 0780381335
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research ♦ Reading
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2003-10-22
Publisher Place Canada
Rights Holder Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Size (in Bytes) 329.24 kB
Page Count 5
Starting Page 809
Ending Page 813


Source: IEEE Xplore Digital Library