Composites with tuned effective magnetic permeability

Pendry et al. J. B. Pendry, A. J. Holden, D. J. Robbins, and W. J. Stewart, IEEE Trans. Microwave Theory Tech. 47, 2075 1999 and Smith et al. D. R. Smith, W. J. Padilla, D. C. Vier, S. C. Nemat-Nasser, and S. Schultz, Phys. Rev. Lett. 84, 4184 2000 have shown that the effective magnetic permeability, , of free space can be rendered negative over a certain frequency range by a periodic arrangement of very thin conductors with suitable magnetic resonance properties, the so-called split-ring resonators. Because of its rather bulky architecture, this structure does not lend itself to a proper integration into a reasonably thin real composite structural panel. To remedy this fundamental barrier, we invented a new magnetic resonator consisting of very thin folded plates that are suitably nested within one another to form folded-doubled resonators FDRs that can be integrated into an actual composite panel. Measurements, using a focused beam electromagnetic characterization system combined with time-domain numerical simulations of the reflection and transmission coefficients of such a composite slab have revealed that indeed the composite has a negative over a frequency range of about 9.1–9.35 GHz S. Nemat-Nasser, S. C. Nemat-Nasser, T. A. Plaisted, A. Starr, and A. Vakil Amirkhizi, in Biomimetics: Biologically Inspired Technologies, edited by Y. Bar Cohen CRC Press, Boca Raton, FL, 2006 . Thus, it has become possible to construct a structural composite panel with negative index of refraction by simultaneously creating negative effective and V. G. Veselago, Sov. Phys. Usp. 10, 509 1968 ; R. A. Shelby, D. R. Smith, and S. Schultz, Science 292, 77 2001 ; A. F. Starr, P. M. Rye, D. R. Smith, and S. Nemat-Nasser, Phys. Rev. B 70, 113102 2004 . © 2007 American Institute of Physics. DOI: 10.1063/1.2751084