Coaxial Cable Bragg Grating Sensors for Large Strain Measurement


In order to ensure the continued stability of civil structures, such as dams, bridges, and buildings, in situ strain monitoring is of notable importance, especially for structures that possess large strains. A coaxial cable Bragg grating (CCBG) is reported for the first time, and the sensor's capacity for large range strain measurement is demonstrated. The sensor device is comprised of regularly spaced periodic discontinuities along a coaxial cable. The discontinuities are fabricated using a computer numerical control (CNC) machine to drill holes through the cable diameter. Each discontinuity generates a weak reflection to the electromagnetic wave propagating inside the cable. Through the superposition of the numerous weak reflections, a strong reflection is formed at discrete frequencies in accordance with Bragg grating theory. By monitoring the resonant frequency shift of the sensor's reflection or transmission spectra, a minimum sensitivity of lOOue and a maximum range of 50000µe (5%) are demonstrated for axial strain measurements. The temperature response of various types of CCBGs has been investigated. The experimental results show that this CCBG performs well in terms of both linearity and sensitivity.

Meeting Name

57th International Instrumentation Symposium (2011: Jun. 20-24, St. Louis, MO)


Electrical and Computer Engineering

Keywords and Phrases

Axial strain; Bragg grating sensors; Civil structure; Computer numerical control machines; Discrete frequencies; Drill hole; Grating theory; In-situ; Large strains; Resonant frequency shift; Sensor device; Temperature response; Transmission line; Transmission spectrums, Bragg gratings; Cables; Coaxial cables; Computer control systems; Electromagnetic wave propagation; Electromagnetic waves; Instruments; Monitoring; Natural frequencies; Sensors; Strain; Strain gages, Strain measurement; Coaxial cable Bragg grating; Structural health monitoring; Transmission line theory

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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© 2011 International Society of Automation, All rights reserved.

Publication Date

01 Jun 2011