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.

通过电磁（EM）谐振器启用的无源无线传感器继承了低成本和绿色环保的优点。但是，裂纹位置的不确定性将导致灵敏度变化，这与工作模式和场分布紧密相关。本文提出了一种圆柱环形介质谐振器（CRDR）来解决这个问题。根据EM谐振器的形状扰动，裂纹的存在会导致存储的磁能比裂纹内部的存储电能增加，从而导致谐振频率移至低频区域。通过与圆柱介质谐振器（CDR）的比较，在仿真和实验中都证明了基于所提出的CRDR的传感原理和裂纹检测能力。