Metamaterial

Metamaterial

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  MetamaterialsAnd Its clocking Presented By P. KIRAN(09F01A0488) Under the esteemed guidance of B. V. V. Ravindra Babu ,M.Tech. ELECTRONICS AND COMMUNICATION ENGINEERING
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  Presentation Outline  Introductionto Metamaterials  Definition of Metamaterial  How Metamaterials work  Time Line  What are Negative Index Metamaterials (NIMs)? Negative Index Metamaterial Features Negative Refraction  Applications  Conclusion
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  Introduction to Metamaterials Meta:Greek prefix meaning “Beyond”
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  Introduction to Metamaterials: Whyare they called Metamaterials?  Existing materials only exhibit a small subset of electromagnetic properties theoretically available  Metamaterials can have their electromagnetic properties altered to something beyond what can be found in nature.  Can achieve negative index of refraction, zero index of refraction, magnetism at optical frequencies, etc.
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  Introduction to Metamaterials:
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  Definition of Metamaterial: “Metamaterial”coined in the late 1990’s  Any material composed of periodic, macroscopic structures so as to achieve a desired electromagnetic response can be referred to as a Metamaterial very broad definition:  Others prefer to restrict the term Metamaterial to materials with electromagnetic properties not found in nature  Still some ambiguity as the exact definition
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  Veselago first studiesthe effect a negative permittivity and permeability has on wave propagation 1968 Pendry proposes wire structures to realize a negative permittivity1996 Pendry proposes Split Ring Resonators (SRR’s) to realize a negative permeability Pendry proposes another wire structures to realize a negative permittivity 1999 2000 T I M E L I N E
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  How Metamaterials Work •Example: How to achieve negative index of refraction • negative refraction can be achieved when both µr and εr are negative • negative µr and εr occur in nature, but not simultaneously • silver, gold, and aluminum display negative εr at optical frequencies • resonant ferromagnetic systems display negative µr at resonance rrn    1 ))(( ))(( 2/2/ 2/1           j jj jj rr e ee ee
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  Negative Refraction n >0 n > 0n < 0 Snell’s Law at the interface between a negative index material and a positive index material: ti nn  sinsin 21          it n n  sinsin 2 11 Refracted beam will be opposite to the normal as shown in the animation above.
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  Metamaterials beyond negativeindex Low index metamaterials Indefinite media High index metamaterials Shrinkage of devices Cloaking Single-negative media Parallel beam formation
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  Applications • Terahertz requirement •Photonic applicati • Cloaking devices • Radar applications • Mobile applications
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  conclusion Introduction of metamaterialsin 1990’s opened new possibilities in electromagnetics.  Successful implementation of metamaterial technology in the microwave spectrum.  Inherent difficulties exist in fabricating optical metamaterials  Most work to date related to modeling proposed designs
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  References: • Smith, D.R., et al., Phys. Rev. Lett. (2000) 84, 4184 • Pendry, J. B., et al., IEEE Trans. Microw. Theory Tech. (1999) 47, 2075 • Veselago, V. G., Sov. Phys. Usp. (1968) 10, 509 • www.google.com • www.nanotechnology.bilkent.edu.tr/research%20areas /documents/mm-waveleft-handed.htm • http://en.wikipedia.org/wiki/Metamaterial
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  Copyright 2003 Applied Logic Engineering
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  Copyright 2003 Applied Logic Engineering