Characterization of a Patch Antenna Sensor’s Resonant Frequency Response in Identifying the Notch-Shaped Cracks on Metal Structure

Abstract

Patch antenna sensor is a novel sensor that has great potential in structural health monitoring. The two resonant frequencies of a patch antenna sensor are affected by the crack on its ground plane, which enables it to sense the crack information. This paper presents a detailed characterization of the relationship between the resonant frequencies of a patch antenna sensor and notch-shaped cracks of different parameters, including the length, the orientation, and the center location. After discussing the principle of crack detection using a patch antenna sensor, a parametric study was performed to understand the response of the sensor’s resonant frequencies to various crack configurations. The results show that the crack parameters affect the resonant frequencies in a way that can be represented by the crack’s cutting effect on the sensor’s current flow. Therefore, we introduced a coefficient φ to comprehensively describe this interaction between the crack and the current distribution of the antenna radiation modes. Based on the definition of coefficient φ, an algorithm was proposed for predicting the resonant frequency shifts caused by a random notch-shaped crack and was verified by the experimental measurements. The presented study aims to provide the foundation for the future use of the patch antenna sensor in tracking the propagation of cracks of arbitrary orientation and location in metal structures.

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“… Antenna crack sensor: ( a ) schematic configuration of a patch antenna, ( b ) antenna sensor with crack, and ( c ) effect of cracks on the current model of the sensor [ 54 ]. …”

Complementary Split-Ring Resonator (CSRR)-Loaded Sensor Array to Detect Multiple Cracks: Shapes, Sizes, and Positions on Metallic Surface

“…In [3], a 3×3 cross-shaped passive FSS is an array structure. In [12], the crack length was varied from 0 mm to 14 mm for two typical cases (30° and 60° rotations) and a prominent change in the measured resonance frequency was observed for cracks longer than 4 mm. The satisfactory performances of expensive RFID tags have been realized with the addition of external sensors [13].…”

Method of Monitoring Cracks in a Metal Structure Based on Dual-Chip RFID Antenna Sensor

“…The influence of artificial machining cracks and actual cracks on the experimental are equal [6], therefore, a penetrating slot with a width of 0.5 mm is introduced to simulate the crack (see Figure 1a). The slot extends from the center of the patch to the other patch edge in steps of 4 mm.…”

“…Deshmukn and Huang first applied patch antennas to the identification of fatigue cracks in metal structures [3]. Subsequently, Yi, Liu and Ke et al [4][5][6] also investigated the crack test results of patch antennas, but the wired connection was mainly used.…”