Wireless Sensing in Complex Electromagnetic Media: Construction Materials and Structural Monitoring


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Ozbey B., DEMİR H. V. , KURÇ Ö., ERTÜRK V. B. , ALTINTAŞ A.

IEEE SENSORS JOURNAL, vol.15, no.10, pp.5545-5554, 2015 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 15 Issue: 10
  • Publication Date: 2015
  • Doi Number: 10.1109/jsen.2015.2441555
  • Journal Name: IEEE SENSORS JOURNAL
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.5545-5554
  • Keywords: Wireless passive sensor, displacement sensor, strain sensor, nested split ring resonator (NSRR), concrete, reinforcing bar (rebar), complex medium, structural health monitoring (SHM), REINFORCED-CONCRETE WALLS, STRAIN SENSOR, ANTENNAS, PH, INTERROGATION, DEFORMATION, TEMPERATURE, PRESSURE

Abstract

In this paper, wireless sensing in the presence of complex electromagnetic media created by combinations of reinforcing bars and concrete is investigated. The wireless displacement sensing system, primarily designed for use in structural health monitoring (SHM), is composed of a comb-like nested split-ring resonator (NSRR) probe and a transceiver antenna. Although each complex medium scenario is predicted to have a detrimental effect on sensing in principle, it is demonstrated that the proposed sensor geometry is able to operate fairly well in all scenarios except one. In these scenarios that mimic real-life SHM, it is shown that this sensor exhibits a high displacement resolution of 1 mu m, a good sensitivity of 7 MHz/mm in average, and a high dynamic range extending over 20 mm. For the most disruptive scenario of placing concrete immediately behind NSRR, a solution based on employing a separator behind the probe is proposed to overcome the handicaps introduced by the medium. In order to obtain a one-to-one mapping from the measured frequency shift to the displacement, a numerical fit is proposed and used. The effects of several complex medium scenarios on this fit are discussed. These results indicate that the proposed sensing scheme works well in real-life SHM applications.