A Passive Wireless Crack Sensor Based on Patch Antenna with Overlapping Sub-Patch.

Songtao Xue,Guochun Wan,Liyu Xie,Tao Ding,Zhuoran Yi

doi:10.3390/s19194327

Songtao Xue, Guochun Wan + Show 3 more

Open Access

https://doi.org/10.3390/s19194327

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Abstract

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.

Highlights

Nowadays, bridges, civil architectures, and mechanical engineering systems continue to provide service despite aging and associated damage accumulation [1]
The relationship between the fundamental resonant frequency in longitudinal direction and the dimension of the crack sensors is described in Equation (4), and the length of the combined radiation patch Lc is calculated by Equation (10)
This paper introduces a novel crack sensor based on a patch antenna with an overlapping sub-patch

Summary

Introduction

Bridges, civil architectures, and mechanical engineering systems continue to provide service despite aging and associated damage accumulation [1]. A crack’s existence and growth can be directly monitored by crack sensors, such as the optical fiber grating sensor [4,5], capacitance-based sensor [6], conductive area sensor [7], resistance based sensor [8], infrared sensor [9], and optical sensor [10,11]. These cable-powered sensors usually show reliable accuracy and high stability.

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Conclusion