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

fYear

2004

fDate

24-27 Oct. 2004

Firstpage

1415

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Sensors, 2004. Proceedings of IEEE

Print_ISBN

0-7803-8692-2

Type

conf

DOI

10.1109/ICSENS.2004.1426450

Filename

1426450