Metamaterials are artificial structures designed to have unique electromagnetic properties not found in nature, such as a negative refractive index. They are composed of meta-atoms that can manipulate electromagnetic waves at scales smaller than the wavelength of light. Metamaterials have applications in invisibility cloaking, super lenses, compact antennas, absorbing electromagnetic radiation, and mitigating seismic waves. However, designing metamaterials for specific wavelengths is challenging, and they do not work perfectly and are very expensive.

1. METAMATERIALS
A GREAT ACHIEVEMENT OF MATERIAL SCIENCE
Sakti Prasanna
Muduli

2. SCOPE
 What are Metamaterials
 Working principle
 Types
 Applications
 Limitations

3. INTRODUCTION
Metamaterials are artificial structures
designed to have unique properties not
found in common materials. Such as
Negative refractive index, elasticity, can
modify sound waves, enhance radiated
power etc.
NOTE:-
“META”- above, higher, superior or beyond
What are Metamaterials
?

4. HISTORY
 Winston E Kock developed material that had similar
characteristics to that of metamaterial in 1940.
 Russian Physicist Victor Veselago(1929) explained about
the properties exact opposite to common materials in1967.
 Prof. John Pendry(1943) suggested the practical method
for making metamaterials in 1999.
Prof. John pendry Victor Veselago

5. INTERESTING ABOUT THE TOPIC:-
 Interesting things about the topic are
metamaterials can be used to make invisible
cloak, super lenses beyond the diffraction
limit, flexible electronic devices etc.

6. WORKING PRINCIPLE
Like unit cell crystal structure of common materials, unit
component of metamaterial is called “Meta-atom” whose
structure is just like a MOSFET. This goes under nano
technology.

7. This is a metallic resonator structure whose
dimensions allow the resonant oscillation of
electromagnetic waves. Structure is shown in
the above fig.

8. NEGATIVE REFRACTIVE INDEX
Magnetic permeability(µ) and electric permittivity(€)
of a metamaterial can be –ve simultaneously ;which
results in –ve RI. Graphically shown bellow

10. TYPES OF METAMATERIALS
Metamaterials are classified in to following
types:
 Electromagnetic
 Acoustic
 Seismic

11. 1.ELECTROMAGNETIC METAMATERIALS
Common refractive material metamaterial
Light is an electromagnetic wave. Due to -ve RI light wave
is treated by metamaterials as above

12. 2.ACOUSTIC METAMATERIALS
 Acoustic metamaterials control and direct
manipulate the sound wave(a transverse
wave).
This can be used in following :
1. Sound Proof Room
2. Sonar Blocking(Invisible submarines)

13. 3.SEISMIC METAMATERIALS
 These metamaterials are designed to
counteract the adverse effect of seismic
waves like longitudinal surface waves.
1.volcanic vibration
2.Earthquake

14. APPLICATIONS
We can describe the applications in following
points:
 Invisibility(cloaking device)
 Super lenses
 Small size Antennas
 Wave Absorber
 Seismic Protection

15. INVISIBILITY
Due to –ve RI of the material,
It can bend the light wave to
backside of an opaque object
and make it go in same direction
as it falls on the object. As a result
one can observe the absence of
That object visually.

16. SUPER LENSES
Super lenses consist of metamaterials to
achieve resolution beyond the diffraction
limit. Which are able to view live viruses and
may be even bits of DNA.
ANTENNAS
As metamaterials can enhance radiated
power, Small size antennas like radars can be
designed with improved performances.

17. ABSORBER
Metamaterial can absorb large amount of
electromagnetic radiation by varying its
magnetic permeability and electric
permittivity.
SEISMIC PROTECTION
As previously described metamaterials can be
used to manipulate seismic waves like destructive
surface waves.

18. LIMITATIONS
1. For smaller wavelength
,smaller unit is required to
design.
2. Different wavelengths
require meta-atom of
different dimensions.
3. Practically it does not
work perfectly.
4.It is very expensive.

19. REFERENCES
 https://en.wikipedia.org/wiki/Metamaterial
 http://science.howstuffworks.com/invisible-tank1.htm
 http://phys.org/tags/metamaterials/
 www.metamaterial.com/