Passive wireless antenna sensor for strain and crack sensing-electromagnetic modeling, simulation, and testing

• Published in: Smart materials and structures Vol. 22; no. 8; pp. 85009 - 1-17
• Main Authors: Yi, Xiaohua, Cho, Chunhee, Cooper, James, Wang, Yang, Tentzeris, Manos M, Leon, Roberto T
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.08.2013; Institute of Physics
• Subjects: Antennas; Cracks; Exact sciences and technology; Flaw detection; Fundamental areas of phenomenology (including applications); General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Interrogation; Measurement and testing methods; Physics; Radio frequency identification; Readers; Sensors; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Solid mechanics; Strain; Structural and continuum mechanics; Nondestructive testing; Tensile tests; Measuring methods; Passive system; Electromagnetic fields; Radiofrequency; Strain sensors; Field distribution; Resonance frequency; Wireless network; Modelling; Electromagnetic properties; Antennas; Fatigue cracks; Monitoring
• ISSN: 0964-1726; 1361-665X
• DOI: 10.1088/0964-1726/22/8/085009

This research investigates a passive wireless antenna sensor designed for strain and crack sensing. When the antenna experiences deformation, the antenna shape changes, causing a shift in the electromagnetic resonance frequency of the antenna. A radio frequency identification (RFID) chip is adopted for antenna signal modulation, so that a wireless reader can easily distinguish the backscattered sensor signal from unwanted environmental reflections. The RFID chip captures its operating power from an interrogation electromagnetic wave emitted by the reader, which allows the antenna sensor to be passive (battery-free). This paper first reports the latest simulation results on radiation patterns, surface current density, and electromagnetic field distribution. The simulation results are followed with experimental results on the strain and crack sensing performance of the antenna sensor. Tensile tests show that the wireless antenna sensor can detect small strain changes lower than 20 μ , and can perform well at large strains higher than 10 000 μ . With a high-gain reader antenna, the wireless interrogation distance can be increased up to 2.1 m. Furthermore, an array of antenna sensors is capable of measuring the strain distribution in close proximity. During emulated crack and fatigue crack tests, the antenna sensor is able to detect the growth of a small crack.