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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