A cylindrical ring dielectric resonator based passive wireless sensor for position insensitive crack monitoring

Passive wireless sensors enabled by the electromagnetic (EM) resonator inherit the merits of low cost and green in power consumption. The uncertainty of the crack location, however, will cause a sensitivity variation, which is tightly related to the operating mode and field distribution. A cylindrical ring dielectric resonator (CRDR) is proposed to cope with this issue in this paper. According to the shape perturbation of the EM resonator, the presence of the crack can cause an increase in the stored magnetic energy over the stored electric energy inside the crack, resulting in a resonant frequency shift to the lower frequency region. By comparing with cylindrical dielectric resonator (CDR), the sensing principle and crack detection capability based on the proposed CRDR is demonstrated in both simulation and experiment. The information gathered from this type of sensor can be used to support predictive maintenance, repair, and decision making for structural health monitoring (SHM) in extreme environments. (C) 2020 Elsevier B.V. All rights reserved.