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Metamaterials And Its clocking
Presented By
P. KIRAN (09F01A0488)
Under the esteemed guidance of
B. V. V. Ravindra Babu ,M.Tech.
ELECTRONICS AND COMMUNICATION ENGINEERING
Presentation Outline
Introduction to Metamaterials
Definition of Metamaterial
How Metamaterials work
Time Line
What are Negative Index Metamaterials (NIMs)?
Negative Index Metamaterial Features
Negative Refraction
Applications
Conclusion
Introduction to Metamaterials
Meta
Material
Metamaterial
Meta: Greek prefix meaning “Beyond”
Introduction to Metamaterials:
Why are 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.
Introduction to Metamaterials :
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
Veselago first studies the 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
TIME LINE
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
jjrr
e
ee
ee
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 sinsin2
11
Refracted beam will be opposite to the normal as shown in the animation above.
Metamaterials beyond negative index
Low index metamaterials
Indefinite media
High index metamaterials
Shrinkage of devices
Cloaking
Single-negative media
Parallel beam formation
Applications
• Terahertz requirement
• Photonic applicati
• Cloaking devices
• Radar applications
• Mobile applications
conclusion
Introduction of metamaterials in 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
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
Copyright 2003 Applied
Logic Enginee
ring
Copyright 2003 Applied
Logic Enginee
ring
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