A Novel Dual Modality Sensor With Sensitivities to Permittivity, Conductivity, and Permeability

• Published in: IEEE sensors journal Vol. 18; no. 1; pp. 356 - 362
• Main Authors: Salas Avila, Jorge R., Kin Yau How, Mingyang Lu, Wuliang Yin
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Capacitive sensors; Coiling; Coils; combined sensing; Coupling; Couplings; dual modality; eddy-current testing; EM sensor; Inductive coupling; Magnetic field measurement; Permeability; Permittivity; Permittivity measurement; Planar sensors; Sensors
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2017.2767380

In this paper, an electromagnetic sensor which can operate simultaneously in capacitive and inductive modalities with sensitivities to permittivity, conductivity, and permeability is developed, and a novel measurement strategy is proposed accordingly. The sensor is composed of two planar spiral coils with a track width of 4 mm, which promotes its capacitive mode. The capacitive coupling is measured in common mode, while the inductive coupling is measured in differential mode. In capacitive mode, the sensor is sensitive to changes in permittivity, i.e., the dielectric material distribution; while in inductive mode, it is sensitive to magnetically permeable material and electrically conductive material. Furthermore, it is demonstrated that the sensor can simultaneously measure dielectric and conductive materials. This novel sensing element has been designed and implemented. Experimental results verified its effectiveness in dual modality measurement.