Show simple item record thomson, douglas j card, dan bridges, greg e 2015-04-09T14:00:08Z 2015-04-09T14:00:08Z 2009-11
dc.identifier.citation Thomson, D.J.; Card, D.; Bridges, G.E., "RF Cavity Passive Wireless Sensors With Time-Domain Gating-Based Interrogation for SHM of Civil Structures," in Sensors Journal, IEEE , vol.9, no.11, pp.1430-1438, Nov. 2009 doi:
dc.description.abstract Many existing sensing technologies for application to the monitoring of large systems or civil structures have a serious deficiency in that they require some type of wired physical connection to the outside world. This causes significant problems in the installation and long term use of these sensors. This paper describes a new type of passive wireless sensor that is based on resonant RF cavities, where the resonant frequency is modulated by a measurand. In the case of a strain sensor, the electrical length of the cavity directly modulates it’s resonant frequency. A probe inside the cavity couples RF signals from the cavity to an externally attached antenna. The sensor can then be interrogated remotely using microwave pulse-echo techniques. Such a system has the advantage of requiring no permanent physical connection between the sensor and the data acquisition system. In this type of sensor the RF interrogation signal is transmitted to the sensor and then re-radiated back to the interrogator from the sensor resulting in a signal strength that decreases with the forth power of distance. This places an upper limit on the distance over which the sensor can be interrogated. Theoretical estimates show that these sensors can be interrogated with sufficient signal-to-noise ratio at distances exceeding 10 m for radiated powers of less than 1 mW. We present results for a strain sensor and a displacement sensor that can be interrogated at a distance of 8 m with a strain resolution of less than 10 ppm and displacement resolution of 0.01 mm, respectively. en_US
dc.description.sponsorship NSERC, ISIS Canada en_US
dc.language.iso en_US en_US
dc.publisher IEEE en_US
dc.subject Passive sensor, radio frequency, resonant cavity, structural health monitoring, wireless sensors en_US
dc.title RF Cavity Passive Wireless Sensors With Time-Domain Gating-Based Interrogation for SHM of Civil Structures en_US
dc.type Article en_US
dc.description.note (c) 2009 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

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