Department of Disaster Mitigation for Structures, Tongji University, Shanghai 200092, China.
Department of Architecture, Tohoku Institute of Technology, Sendai 982-8577, Japan.
Sensors (Basel). 2019 Oct 7;19(19):4327. doi: 10.3390/s19194327.
Monolithic patch antennas for deformation measurements are designed to be stressed. To avoid the issues of incomplete strain transfer ratio and insufficient bonding strength of stressed antennas, this paper presents a passive wireless crack sensor based on an unstressed patch antenna. The rectangular radiation patch of the proposed sensor is partially covered by a radiation sub-patch, and the overlapped length between them will induce the resonate frequency shift representing the crack width. First, the cavity model theory is adopted to show how the resonant frequencies of the crack sensor are related to the overlapped length between the patch antenna and the sub-patch. This phenomenon is further verified by numerical simulation using the Ansoft high-frequency structure simulator (HFSS), and results show a sensitivity of 120.24 MHz/mm on average within an effective measuring range of 1.5 mm. One prototype of proposed sensor was fabricated. The experiments validated that the resonant frequency shifts are linearly proportional to the applied crack width, and the resolution is suitable for crack width measuring.
用于变形测量的整体贴片天线被设计为承受压力。为避免受力天线的应变传递率不完整和结合强度不足的问题，本文提出了一种基于非受力贴片天线的无源无线裂缝传感器。所提出的传感器的矩形辐射贴片部分被一个辐射子贴片覆盖，它们之间的重叠长度将引起代表裂缝宽度的共振频率移动。首先，采用空腔模型理论来展示裂缝传感器的共振频率如何与贴片天线和子贴片之间的重叠长度有关。这一现象通过使用 Ansoft 高频结构模拟器（HFSS）进行数值模拟得到了进一步验证，结果表明在 1.5mm 的有效测量范围内平均灵敏度为 120.24MHz/mm。制作了一个传感器原型。实验验证了共振频率的移动与施加的裂缝宽度呈线性比例关系，分辨率适合裂缝宽度测量。
