Analysis & Design of Met a Material

8/2/2019 Analysis & Design of Met a Material

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Analysis & Design of Metamaterialfor

Electromagnetic Cloaking

Tarun Kumar (Enroll. No. 10402011)PhD Scholar, ECE Dept. JIIT, Noida

[email protected]: Prof. N. Kalyansundaram

(End Sem

ester progress report for July-Dec 2011)


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Acknowledgment: DPMC Members and Interested attendees

Outlines: Introduction Electromagnetic Properties of Ferromagnetic Microwires

Achieving DNG behavior with Ferromagnetic Microwiresarray

Analysis of Microwires array

Conclusion

References


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Introduction

Research on metamaterials has been basically driven bythe development of microstructures relying on the artificialmagnetism generated by split ring resonators (SRRs) orother types of current loops.

This approach often requires the combination of two

separate arrays being able to combine, in a given frequencyrange, a double (electric and magnetic) negative response.

Ferromagnetic microwires are known to be suitableparticles in the design of MTMs. The main advantage ofusing such particles lies on their capability to provide

double-negative behaviour with only one single element.

On the one hand, ferromagnetic microwires have anelectrical response similar to conductive wires so a negativepermittivity can be created by an array of such wires.


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Electromagnetic Properties ofFerromagnetic Microwires

FIG. 1. (a) view of a partially removed glasscoat amorphous microwire ,(b) schematicview of the waveguide setup employed inthe experiments for configurations includinga dc current source.[6]

The use of ferromagnetic materials asconstituents of microstructured deviceshas the important asset of providingtunability of the EM responses as afunction of an adjustable applied

magnetic field. It is known that theferromagnetic resonance FMRphenomenon typically occurs atmicrowave frequencies for differenttypes materials.[6]

The employed glass coated amorphousmicrowires have a general compositionCo100xFex0.725Si12.5B15. Parameter x

represents here the variable fraction ofiron in the alloy .[6]


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Contd..

The effective permeability and the propagationconstant for the extraordinary waves supported by themedium are, respectively,given by


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Contd

Fig. 2. Real and imaginary part of the effective permeability for

the consideredferromagnetic microwires.[1]


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Achieving DNG behavior with FerromagneticMicrowires array

FIG. 3. The periodic structure iscomposed of infinite wiresarranged in a simple cubic lattice,

joined at the corners of thelattice. [5]

If the density of electrons in thesewires is n, the density of these activeelectrons in the structure as a whole isgiven by the fractionof space occupied by the wire, [5]

(11)

(13)

Following expression gives aneffective dielectric function of thestructure:[5]

where is the conductivity of the metal.

(12)


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Analysis of microwires array

y

z

x

d

EE

E

Ek k

Fig.-5: The geometry of the planar regular array of microwires[2]


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Analysis is to be explained onboard!!


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Conclusion

The analysis of the scattering from FerromagneticMicrowires array provides physical insight into theinteraction between electromagnetic fields andferromagnetic microwires, contributing with an intuitivevision, which can be helpful for the development ofprototypes.

The use of ferromagnetic materials as constituents ofmicrostructured devices has the important asset ofproviding tunability of the EM responses as a function of anadjustable applied magnetic field.

On the basis of analysis of 2-D planar array, a 3-D array canbe modeled.

Theoretical results are et to be confirmed with simulation


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References[1] Iigo Liberal, Iigo Ederra, Cristina Gmez-Polo, Alberto Labrador, Jose

Ignacio Prez Landazbal, and Ramn Gonzalo, Theoretical Modelingand Experimental Verification of the Scattering From a FerromagneticMicrowire, IEEE Transaction on Microwave Theory and Techniques,Vol. 59, no. 3, March 2011.

[2]S. Tretyakov, Analytical Modeling in Applied Electromagnetics.Norwood, MA: Artech House, 2003.

[3] J. Carbonell, H. Garcia-Miquel, and J. Sanchez-Dehesa, Doublenegative metamaterials based on ferromagnetic microwires, Phys.Rev. B, Condens. Matte.

[4] D. Pozar, Microwave Engineering. New York: Wiley, 2005.r, vol. 81, no.2, 2010, Art. ID 024401.

[5] J. Pendry, A. Holden, W. Stewart, and I. Youngs, Extremely low

frequency plasmons in metallic mesostructures, Phys. Rev. Lett., vol.76, no. 25, pp. 47734776, 1996.

[6] H. Garca-Miquel, J. Carbonell,a and J. Snchez-Dehesa Left handedmaterial based on amorphous ferromagnetic microwires tunable by dccurrent APPLIED PHYSICS LETTERS 97, 094102 2010.

[7] Felsen L.B. and N. Marcuvitz, Radiation and Scattering of WavesPiscataway, NJ: IEEE Press, 1991.


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Analysis & Design of Met a Material