Evaluation of near-field electromagnetic shielding effectiveness at low frequencies

Yessica Arellano, Andrew Hunt, Olivier Haas

    Research output: Contribution to journalArticlepeer-review

    10 Citations (Scopus)
    236 Downloads (Pure)


    Magnetic induction tomography (MIT) is a novel technology for flow measurement offering significant promise in the measurement of multiphase flows containing low-conductivity fluids such as saline water. Such measurements rely on optimal effective shielding to avoid external field interference and extraneous capacitive coupling that can lead to false readings and overestimations of the eddy current-induced fields. The performance of various attenuation materials in the low megahertz frequency spectrum is presented and compared with outcomes from a numerical computational method. The results demonstrate that the shielding mechanism that prevails at low frequencies is that of reflection. Consequently, hard shields such as metals show superior wave attenuation performance for MIT systems operating below 13 MHz. For higher frequencies, the absorption effect on the incident wave path within soft electromagnetic shields presents enhanced shielding properties. This paper also explores the limitations of traditional testing geometry for shielding effectiveness and proposes an alternative approach to near-field, free-space measurement for MIT sensors. The proposed semi-enclosed approach shows enhanced shielding effectiveness measurements compared with the traditional transversal barrier method. The proposed method was used to assess the electromagnetic shielding effectiveness of ferromagnetic and various metallic materials.

    Original languageEnglish
    Article number8481434
    Pages (from-to)121 - 128
    Number of pages8
    JournalIEEE Sensors Journal
    Issue number1
    Early online date4 Oct 2018
    Publication statusPublished - 1 Jan 2019

    Bibliographical note

    © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.


    • Eddy currents
    • electromagnetic compatibility
    • electromagnetic induction
    • electromagnetic shielding
    • tomography

    ASJC Scopus subject areas

    • Instrumentation
    • Electrical and Electronic Engineering


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