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

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.

[1]  Wuliang Yin,et al.  Sensitivity Formulation Including Velocity Effects for Electromagnetic Induction Systems , 2010, IEEE transactions on magnetics.

[2]  Wuliang Yin,et al.  A multi-frequency impedance analysing instrument for eddy current testing , 2006 .

[3]  Wuqiang Yang,et al.  Planar capacitive sensors – designs and applications , 2010 .

[4]  R. J. Ditchburn,et al.  Eddy-Current Nondestructive Inspection with Thin Spiral Coils: Long Cracks in Steel , 2003 .

[5]  Enrong Wang,et al.  Application of low frequency ECT method in noncontact detection and visualization of CFRP material , 2017 .

[6]  Philip J. Withers,et al.  Noncontact Characterization of Carbon-Fiber-Reinforced Plastics Using Multifrequency Eddy Current Sensors , 2009, IEEE Transactions on Instrumentation and Measurement.

[7]  Charles V. Sammut,et al.  Eddy current sensing using planar coils , 2012, IEEE Instrumentation & Measurement Magazine.

[8]  Anthony J. Peyton,et al.  Electromagnetic induction tomography , 2015 .

[9]  Wuqiang Yang,et al.  Hardware design of electrical capacitance tomography systems , 1996 .

[10]  Xiaokang Yin,et al.  Non-destructive evaluation of composite materials using a capacitive imaging technique , 2012 .

[11]  R. J. Ditchburn,et al.  Planar rectangular spiral coils in eddy-current non-destructive inspection , 2005 .

[12]  Udo Kaatze,et al.  Measuring the dielectric properties of materials. Ninety-year development from low-frequency techniques to broadband spectroscopy and high-frequency imaging , 2012 .

[13]  Jack Blitz,et al.  Electrical and Magnetic Methods of Nondestructive Testing , 2020 .

[14]  Jiang Long,et al.  A metamaterial-inspired combined inductive-capacitive sensor , 2014, Sensing Technologies + Applications.

[15]  Wuliang Yin,et al.  The Design of a Digital Magnetic Induction Tomography (MIT) System for Metallic Object Imaging Based on Half Cycle Demodulation , 2011, IEEE Sensors Journal.

[16]  Joshua R. Smith,et al.  Electric field imaging , 1999 .

[17]  Boby George,et al.  A Combined Inductive–Capacitive Proximity Sensor for Seat Occupancy Detection , 2010, IEEE Transactions on Instrumentation and Measurement.

[18]  E. M. Freeman,et al.  A method of computing the sensitivity of electromagnetic quantities to changes in materials and sources , 1994 .

[19]  Javier García-Martín,et al.  Non-Destructive Techniques Based on Eddy Current Testing , 2011, Sensors.

[20]  Kai Xu,et al.  Level measurement for saline with a small surface area using high frequency electromagnetic sensing technique , 2017 .

[21]  Wael W. El-Dakhakhni,et al.  Coplanar capacitance sensors for detecting water intrusion in composite structures , 2008 .

[22]  Anthony J. Peyton,et al.  Understanding the coupling mechanism in high frequency EMT. , 2003 .

[23]  Subhas C. Mukhopadhyay,et al.  Novel Planar Electromagnetic Sensors: Modeling and Performance Evaluation , 2005, Sensors (Basel, Switzerland).