2. What is a meta material?
A periodic material that derives its
properties from its structure rather
than its components
3. PROPERTIES OF META MATERIALS:
They are assemblies of multiple individual elements fashioned from
conventional microscopic materials such as metals or plastics, but the
materials are usually arranged in periodic patterns.
Their precise shape, geometry, size, orientation and arrangement can
affect the waves of light or sound in an unconventional manner, creating
material properties which are unachievable with conventional materials.
The primary research in meta materials investigates materials with
negative refractive index.
The research in meta materials is interdisciplinary and involves such fields
as electrical engineering, electromagnetics, solid state physics, microwave
and antennae engineering, optoelectronics, classic optics,
material sciences, semiconductor engineering, Nano science and others
4. HISTORY OF META MATERIALS
Winston E. Kock developed materials that had similar characteristics to
metamaterials in the late 1940s.
Materials, which exhibited reversed physical characteristics were first
described theoretically by Victor Veselago in 1967.
A little over 30 years later, in the year 2000, Smith et al. reported the
experimental demonstration of functioning electromagnetic metamaterials
by horizontally stacking, periodically, split-ring resonators and thin wire
structures.
Later, a method was provided in 2002 to realize negative index
metamaterials using artificial lumped-element loaded transmission lines in
micro strip technology.
5. At microwave frequencies, the first real invisibility cloak was realized in 2006.
However, only a very small object was imperfectly hidden.
In 2007, one researcher stated that for metamaterial applications to be
realized, several goals must be achieved.
6. • Negative refractive index is an important characteristic in metamaterial
design and fabrication. As reverse-refraction media, these occur when
both permittivity ε and permeability µ are negative.
• In negative index metamaterials (NIM), both permittivity and permeability
are negative resulting in a negative index of refraction.
7. INVISIBILITY USING META MATERIALS
The things which our eyes are not able to see are considered as “Invisible.
Light is neither absorbed nor reflected by the objects, passing like water
flowing around a rock
Meta-material is a type of composite material that has unusual
electromagnetic properties.
. According to the researchers, light rays incident on the material would be
bent around the object, only to emerge on the other side in exactly the
same direction as they began.
9. Coat
Exposure
Develop
plain Si
wafer
coat with HMDS
to promote
adhesion
coat with SU-8
20xx photoresist
using spin
coater
soft bake
@95° to
evaporate
solvent and
cut into
pieces
UV exposure
for xx
seconds
flip 90° and
expose
again
post bake at
first 65° then
95° to promote
crosslink
formation
submerge in PM
acetate to
dissolve
unexposed
photoresist (20
min）
submerge in
isopropanol to
wash away all
remnants—final
structure
10. 2004:
• Miniaturized antennas based on negative permittivity materials—Lucent
Technologies
• Metamaterial scanning lens antenna systems and methods—The Boeing
Company
2003:
• Metamaterials employing photonic crystal—MIT
• Methods of fabricating electromagnetic metamaterials—The Boeing
Company
2002:
• Resonant antennas—Lucent Technologies
11.
12. APPLICATIONS
There'd be plenty of applications in
the civilian world as well, even for
rudimentary cloaking devices.
For example, you could create
receptacles to shield sensitive
medical devices from disruption by
MRI scanners, or build cloaks to
route cellphone signals around
obstacles.
Potential applications of meta
materials are diverse:
remote aerospace applications,
sensor detection and infrastructure
monitoring,
smart solar power management,
public safety, radomes, high-
frequency battlefield
communication .
lenses for high-gain antennas,
improving ultrasonic sensors, and
even shielding structures from
earthquakes.
13. BARRIERS IN DEVELOPMENT OF META
MATERIALS
Although we have thorough knowledge of theoretical concept of invisibility
but we have not enough practical implementation of these concepts.
Meta-material still needs more consideration and a lot has remained
undiscovered and needs thorough study.
Security concern is another serious issue.
The tiny structures embedded in the metamaterial would have to be
smaller than the wavelength of the electromagnetic rays you wanted to
bend.
That's a tall order for optical invisibility, because the structures would have
to be on the scale of nanometers, or billionths of a meter.
