Title :
A differential capacitive mini-displacement sensor
Author :
Liu, Zutao ; Huang, Qing-An ; Li, Weihua
Author_Institution :
Key Lab. of MEMS of the Minist. of Educ., Southeast Univ., Nanjing, China
Abstract :
The paper describes a micromachined device that offers high sensitivity and wide dynamic range for electronically monitoring the planar displacement caused by other microstructures. The device uses a differential capacitance between overlapped electrodes to sense displacement. The differential capacitance is composed of a suspension electrode mounted on a moving cantilever, and two fixed electrodes located under the suspension electrode. The suspension and fixed electrodes are arranged such that output is a differential readout, eliminating common mode parasitic capacitance. Analytical and numerical modeling results are presented and results of simulating the capacitance prove that it has sensitivity in the range of 90-100 fF/μm and a measurement range of about ±10 μm. A sensor circuit for precise measurement of changes in capacitance is also presented.
Keywords :
capacitance; capacitive sensors; displacement measurement; linear network analysis; microsensors; sensitivity; common mode parasitic capacitance; differential capacitive mini-displacement sensor; differential capacitive sensor; dynamic range; micromachined device; microstructures; moving cantilever; overlapped electrodes; planar displacement; sensitivity; sensor circuit; suspension electrode; Analytical models; Capacitance measurement; Capacitive sensors; Circuit simulation; Dynamic range; Electrodes; Microstructure; Monitoring; Numerical models; Parasitic capacitance;
Conference_Titel :
Sensors, 2004. Proceedings of IEEE
Print_ISBN :
0-7803-8692-2
DOI :
10.1109/ICSENS.2004.1426450
