Wireless micromachined ceramic pressure sensor for high-temperature applications

• Published in: Journal of microelectromechanical systems 2002-08, Vol.11 (4), p.337-343
• Main Authors: Fonseca, M.A., English, J.M., von Arx, M., Allen, M.G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Capacitive sensors; Capacitors; Ceramic materials; Ceramics; Compressors; Detection; Electric power systems; Electromechanical sensors; Electronics; Electronics packaging; Engines; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); High temperature applications; Industrial metrology. Testing; Information retrieval; Infrastructure; Instrumentation for fluid dynamics; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Loop antennas; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Micromachining; Micromechanical devices and systems; Natural frequencies; Nonbibliographic retrieval systems; Physics; Pressure sensors; Resonant frequencies; Sensor phenomena and characterization; Sensors; Telemetry; Turbines; Wireless sensor networks
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2002.800939

In high-temperature applications, such as pressure sensing in turbine engines and compressors, high-temperature materials and data retrieval methods are required. The microelectronics packaging infrastructure provides high-temperature ceramic materials, fabrication tools, and well-developed processing techniques that have the potential for applicability in high-temperature sensing. Based on this infrastructure, a completely passive ceramic pressure sensor that uses a wireless telemetry scheme has been developed. The passive nature of the telemetry removes the need for electronics, power supplies, or contacts to withstand the high-temperature environment. The sensor contains a passive LC resonator comprised of a movable diaphragm capacitor and a fixed inductor, thereby causing the sensor resonant frequency to be pressure-dependent. Data is retrieved with an external loop antenna. The sensor has been fabricated and characterized and was compared with an electromechanical model. It was operated up to 400/spl deg/C in a pressure range from 0 to 7 Bar. The average sensitivity and accuracy of three typical sensors are: -141 kHz Bar/sup -1/ and 24 mbar, respectively.