This document discusses using metamaterials to improve wireless power transfer. It describes how Nikola Tesla experimented with wireless power transmission in the late 1800s. Metamaterials are periodic structures that can achieve unusual electromagnetic properties not found in nature. When placed above a microstrip patch antenna array, metamaterials were shown to increase the antenna gain, radiation efficiency, and total efficiency compared to the antenna array alone. The improved antenna performance when coupled with metamaterials allows for increased wireless power transmission range for applications such as smart grids.

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Wireless Power Transfer Using Metamaterial
Bonded Microstrip Antenna for
Smart Grid WSN

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Outline
• Background
• Microwave Power Transmission
• System Model
• Metamaterials
• Metamaterials used in Microwave Power Transmission
• Conclusion
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Background
Nikola Tesla
Innovations:
• Alternating current
• Wireless power transmission experiments at Wardenclyffe.
• In 1899 he was able to light lamps over 25 miles away without
using wires.
• High frequency current, of a Tesla coil, could light lamps filled
with gas (like neon).
(1856-1943)
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Block Diagram For WPT
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Single Element M.R.P.A.
Design of a Patch Antenna
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Cavity Model For Patch Antenna
 A radiating patch is fabricated on a dielectric
substrate at a small fraction away from ground
plane.
 It is feeded by microstrip line feed technique.
 The region between ground plane and microstip
patch, bounded by electric conductors is a resonance
cavity

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Radiation and Polar Plot
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3-D Radiation Plot Polar Plot
Gain 7.14 dB
Radiation Efficiency -0.8591 dB
Total Efficiency -1.196 dB

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4 x Element Array
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4 element Array of Patch antenna
• Increase the overall gain
• Provide diversity reception
• Cancel out interference from a particular set of directions
• Total radiation
• The Array Factor is a function of the positions of the antennas
in the array and the weights used

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Radiation and Polar Plot
3-D Radiation Plot Polar Plot
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Gain 11.9 dB
Radiation Efficiency -1.4032 dB
Total Efficiency -1.926 dB

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Metamaterial
• Metamaterials are a new class of ordered composites that exhibit exceptional properties not readily
observed in nature.
• A periodic material that derives its properties from its structure rather than its components
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D.R. Smith - “Any material composed of a periodic microscopic structures so as to achieve desired electromagnetic
response can be referred as a metamaterial”.
Metamaterial unit cell Metamaterial structure

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History
• A. Schuster, An Introduction to the Theory of Optics 1904.
• L.I. Mandelshtam, May 5 1944 “In fact, the direction of wave propagation
is determined by its phase velocity, while energy is transported at the
group velocity.”
• A German scientist Victor Veselago in 1967 by his article “The
electrodynamics of substances with simultaneous negative values of ε
and μ”, was able to predict that :
 Metamaterials act in exact opposite manner than natural
materials (like negative refractive index).
 Waves behavior in negative refractive material.
• Dr. John Pendry showed practical method of making metamaterials in
1999 .
 Describes a perfect lens that can focus all four Fourier
components.
• David R. Smith demonstrated experimentally metamaterial in his article
"Experimental verification of a negative index of refraction“.
 The first person to create a functioning cloak of invisibility that
renders an object invisible in microwave wavelengths
V. G. Veselago
Sir John Pendry
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Properties of Metamaterials
Unique Properties Of Metamaterials
• Refractive Index is negative
r r n    
• Opposes Snell’s law
• Opposes Doppler's Effect
• Positive Impedance
• Cherenkov radiation points the other way
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 Due to their unique properties they are propagating in left hand side, they are often called as Left handed
material

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Classification of Material and
Achieving N.R.I.
Classification Of Materials Found In Nature
Achieving Negative Refractive Index (N.R.I.)
• By Using Material Having Negative Permittivity.
 They are often found in nature in some metals and
semiconductor..
 Do not give positive impedance
• By using material having negative Permeability.
 They are rarely exist in nature and that to for very low
frequency
 Do not give positive impedance
• By using material having both permittivity and
permeability negative.
 They are not found in nature.
 They are the combination of above two materials
 Posses positive impedance
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Behavior of Waves With
Metamaterials
• Maxwell equations describe all electromagnetic phenomena.
• Metamterial (Negative refractive index) changes the Maxwell’s equations which inter changes the direction of
propagation of waves.
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Normal material Metamaterial
 Pointing vector represent the direction of
propagation of waves .
Pointing vector
Comparison Of Maxwell’s Equation

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Metamaterial as Lens
• Lens tries to focus the field by applying phase correction to each Fourier
component but it did not provide amplitude amplification.
• Pendry’s proved by his articles that when an evanescent wave is passed
through a matameterial it provides:
 Phase correction
 Amplitude amplification
• Multiple refraction will focus the beam and reflection is zero when there
is no mismatch loss
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Wave propagation through metamaterial
Multiple Refraction Through A Lens Metamaterial Lens

15. Antenna Incorporated with Metamaterial
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M.R.P.A single Element 4 Element M.R.P.A array
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• Array of metamaterial structure that we have proposed had placed above the M.R.P.A. array at a
certain height from ground plane.
• Distance Between antenna and metamaterial lens is based on Impedance matching.

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Comparison of Patch Antenna Result
Without and With Metamaterial
Without metamaterial lens With metamaterial lens
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S-parameters for Patch Antenna
Without and With Lens
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Gain 7.33 dB 8.22 dB
Radiation Efficiency -0.694 dB -0.045 dB
Total Efficiency -1.025 dB -0.662 dB

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Comparison of Antenna Array Result
Without and With Metamaterial
Without metamaterial lens With metamaterial lens
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19. S-parameters for Antenna Array Without
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And With Lens
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Gain 14.05 dBi
Directivity 14.47dBi
Radiation Efficiency --0.2242 dBi

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Free Space Transmission
• The received power is for linear values of
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transmitting antenna gain and it can be seen that Pr
is increasing with increasing value of Gt.
• The receiver antenna will extract the microwave
power and provide to a schottky diode for its
conversion to dc.

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Conclusion
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• Wireless power can be transmitted to an increased range by using metamaterial with
antenna
• Use of metamaterial will improve the antenna performance.
• No altercation is required in antenna structure for achieving better or desired
performance.
• Metamaterial used with antenna can also help in avoiding interference

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Vikaram Singh
Antenna and Microwave Group
Intelligent Communication Lab (INTELCOM)
Mumbai, India
E vikram.singh@intelcomlab.com M +91 9767371987