Quasi-Static Magnetic Field Shielding Using Longitudinal Mu-Near-Zero Metamaterials.

Journal Article (Journal Article)

The control of quasi-static magnetic fields is of considerable interest in applications including the reduction of electromagnetic interference (EMI), wireless power transfer (WPT), and magnetic resonance imaging (MRI). The shielding of static or quasi-static magnetic fields is typically accomplished through the use of inherently magnetic materials with large magnetic permeability, such as ferrites, used sometimes in combination with metallic sheets and/or active field cancellation. Ferrite materials, however, can be expensive, heavy and brittle. Inspired by recent demonstrations of epsilon-, mu- and index-near-zero metamaterials, here we show how a longitudinal mu-near-zero (LMNZ) layer can serve as a strong frequency-selective reflector of magnetic fields when operating in the near-field region of dipole-like sources. Experimental measurements with a fabricated LMNZ sheet constructed from an artificial magnetic conductor - formed from non-magnetic, conducting, metamaterial elements - confirm that the artificial structure provides significantly improved shielding as compared with a commercially available ferrite of the same size. Furthermore, we design a structure to shield simultaneously at the fundamental and first harmonic frequencies. Such frequency-selective behavior can be potentially useful for shielding electromagnetic sources that may also generate higher order harmonics, while leaving the transmission of other frequencies unaffected.

Full Text

Duke Authors

Cited Authors

  • Lipworth, G; Ensworth, J; Seetharam, K; Lee, JS; Schmalenberg, P; Nomura, T; Reynolds, MS; Smith, DR; Urzhumov, Y

Published Date

  • August 3, 2015

Published In

Volume / Issue

  • 5 /

Start / End Page

  • 12764 -

PubMed ID

  • 26234929

Pubmed Central ID

  • PMC4522651

Electronic International Standard Serial Number (EISSN)

  • 2045-2322

International Standard Serial Number (ISSN)

  • 2045-2322

Digital Object Identifier (DOI)

  • 10.1038/srep12764

Language

  • eng