Affiliated with the
Communication & Space
Sciences Laboratory

Novel Electromagnetic Metamaterials

Meta-ferrite Materials

Members of CEARL have recently shown that a properly designed EBG can have surface impedance equivalent to that of a thin magnetic substrate backed by a PEC ground plane.
We call such an artificial ferrite material a meta-ferrite.

 

..: References :..

1-) The Synthesis of Metamaterial Ferrites for RF Applications Using Electromagnetic Bandgap Structures
by Douglas J. Kern, and Dr. Douglas H. Werner
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2-) The Synthesis of Metamaterial Ferrites for RF Applications Using Electromagnetic Bandgap Structures
by D. J. Kern and D. H. Werner
2003 IEEE International Symposium on Antennas and Propagation, Columbus, Ohio, June 22-27.

ABSTRACT: It has been well known for many years that the desirable properties of conventional ferrite materials are seriously degraded for frequencies above 1 GHz. This paper demonstrates that Electromagnetic Bandgap (EBG) structures may be interpreted as an equivalent PEC backed slab of magnetic material with a frequency dependent permeability. This property is exploited in order to develop a design methodology for realizing a metamaterial ferrite, which we call a metaferrite, by means of a Genetic Algorithm (GA) optimization procedure. A High-impedance Frequency Selective Surface (HZ-FSS) is designed by optimizing for a desired surface resistance and reactance at the specified operating frequency or frequencies. These values of surface impedance are shown to be directly related to the real and imaginary parts of the effective permeability of an equivalent magnetic material slab. It will be demonstrated that a properly optimized HZ-FSS can be used to realize a metaferrite structure that retains its desirable magnetic properties at frequencies above 1 GHz. Furthermore, the ability of the design procedure to optimize separately for the real and imaginary parts of the permeability allows for the synthesis of metaferrites with low-loss and either positive or negative values of µ at the desired frequency range of operation. This suggests that properly designed metaferrites may have application to the design of low loss left-handed or double-negative media by providing, in some applications, an alternative to split-ring resonators.




3-) Metaferrites: Using Electromagnetic Bandgap Structures to Synthesize Metamaterial Ferrites
by Douglas J. Kern, Douglas H. Werner, and Mikhail Lisovich
IEEE Transactions on Antennas and Propagation, Vol. 53, No. 4, pp.1382 - 1389, April 2005.

ABSTRACT: A methodology is presented for the design synthesis of metamaterial ferrites, or metaferrites, that retain their desirable magnetic properties at frequencies above 1 GHz. The design synthesis is accomplished by optimizing a high impedance frequency selective surface (HZ-FSS) structure via a genetic algorithm (GA) for the desired effective permeability of an equivalent magnetic substrate backed by a perfect electric conductor ground plane. The ability to optimize the design parameters of these HZ-FSS structures allows for the possibility of synthesizing low-loss dispersive metaferrites with either a positive or a negative real part of the effective permeability at the desired operating frequency band. The results presented in this paper demonstrate five possible metaferrite designs: two with the associated real and imaginary permeabilities
for use as low-loss magnetic materials, and three designs for use as absorbing materials.




4-) Matched Impedance Thin Planar Composite Magneto-Dielectric Metasurfaces
by Zikri Bayraktar, Micah D. Gregory, Xiande Wang, and Douglas H. Werner
IEEE Transactions on Antennas and Propagation, Vol. 60, No. 4, pp. 1910 - 1920, April 2012.

ABSTRACT: A novel methodology is presented for the design synthesis of matched impedance thin planar composite magneto-dielectric metasurfaces. The design synthesis involves optimizing thin, metallo-dielectric metasurfaces comprised of a periodic array of electrically small and rotationally symmetric metallic unit cells which are sandwiched between two thin dielectric layers and backed by a perfectly conducting ground plane. Optimization of the structures is carried out with a genetic algorithm (GA) to obtain a design with electromagnetic properties that are equivalent to a desired matched-impedance homogeneous medium of the same thickness. Optimized design results demonstrate the effectiveness of this new technique in synthesizing thin planar composite matched-impedance magneto-dielectric metasurfaces (MIMDM). To validate the approach, full-wave simulations of the actual metamaterial structure were compared with results obtained by employing an equivalent homogeneous effective medium and found to be in excellent agreement. Several designs are optimized with targeted applications such as substrates for miniaturized patch antennas and electromagnetic absorbing materials.




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