SEMINAR ON THE THEORY OF WIRELESS POWER TRANSFER AND SOME VERY VALUABLE FUTURE PROSPECTS IN THE FIELD

1. WIRELESS POWER TRANSMISSION
USING MICROWAVES
SUBMITTED BY
RUDRA SANKAR BANDYOPDHYAY
(14EC63R08)
RF AND MICROWAVE ENGINEERING
SEPTEMBER, 2014
DEPARTMENT OF ELECTRONICS AND ELECTRICAL COMMUNICATION
ENGINEERING
INDIAN INSTITUTE OF TECHNOLOGY KHARAGPUR

2. CONTENTS
• Introduction
• Problems in present scenario
• History of Wireless Power Transfer
• Description
• Advancement
• Merits, Demerits and Biological Effects
• Conclusion
• References

3. INTRODUCTION
• Process of transfer of power without the aid
of man made conductors
• Power transfer takes places through free
space via microwaves
• Used in cases where wires are inconvenient ,
hazardous or impossible
• Differs from wireless communication as noise
is not a factor in this case

4. PROBLEMS IN PRESENT SCENARIO
• High transmission and distribution loss
• India has highest loss at a whooping 27%
• This process involves higher efficiency , low
power cost and protection from power theft

5. HISTORY OF WIRELESS POWER
TRANSFER
• Nicola Tesla considered the father of wireless
power transfer
• Tesla applied the principle of resonance to
transmit power wirelessly
• William Brown made the first wireless
powered helicopter

6. OPERATION PRINCIPLE

7. MAGNETRON

8. MAGNETRON CONTD…

9. TRANSMITTING ANTENNA
• Should have good directivity to avoid power
losses.
• Microstrip patch, parabolic reflector or slotted
waveguide antenna are best suited
• Efficiency of 95% was achieved using slotted
waveguide antenna

10. TRANSMITTING ANTENNA CONTD…
• For efficient transmission pulses with power
spectral density of a Gaussian function should
be transmitted
• η= (π*Dt*Dr)/(4*λ*r)
• High power handling capacity

11. RECEIVER
• The receiver used in this case is called a
‘RECTENNA’
• As it’s name implies it is a rectifier combined
with an antenna
• The main function of a rectenna is conversion
of the microwave power received into dc
power for practical uses

12. Rectenna

13. DEVIATION FROM IDEAL BEHAVIOUR
• Due to input voltage lower than the lower
than junction voltage or higher than
breakdown voltage
• Possible Solutions
• 1. Increasing Aperture
• 2. Developing more accurate rectifying circuit.

14. Observations

15. EXPERIMENTAL RESULTS
TYPE OF ANTENNA OPERATING FREQUENCY
(GHz)
CONVERSION EFFICIENCY
(%)
PRINTED DIPOLE 2.45 85
CIRCULAR PATCH 2.45 81
PRINTED SQUARE
RHOMBIC
5.6 78
SQUARE PATCH 8.41 66

16. ADVANCEMENT
• Dyengo recently developed microwave based
rectenna and rectifier circuit to achieve
conversion efficiency of 90% at 2 GHz band
• Low pass filter rejects spurious noise by 50dBc
• Heat dissipated as power in microwaves can
be recycled

17. SPACE BASED SOLAR POWER
• Very innovative approach to the use of
microwave power transfer
• Research going on from early 1970s
• Components
• Solar energy collector
• DC to microwave converter
• Large antenna array to beam down
(Microwave) power to ground

18. SCHEMATIC

19. MICROARIAL VEHICLE

20. OPERATION
• Operating frequency of 5.8 GHz
• Used to monitor places where human cannot
reach directly such as a disaster struck area
• No need of refueling
• Highly directed power using phased arrays

21. MERITS
• Remove physical infrastructure “Grids and Towers”
• Cost effective (Remove cost of towers and cables)
• During rain and after natural disaster it is often hard to
manage cables and towers so it removes this difficulty
• Losses during transmission and distribution can be
removed
• Microwaves (electricity) are more environments
friendly. It does not involve emission of carbon gases.
• Electricity bills using conventional supply can be cut to
very low.
• Zero fuel cost

22. DEMERITS
• Biological effects associated with the wireless
transmission of electricity due to the high frequency
microwave signals is the first demerit of this
technology
• This project is a onetime expense but it involves a lot of
initial expenditure. It is expected that the price of
receive electricity through this technology would
decline overtime
• This technology is limited to the use of few
technologies like solar satellites and Tesla grid
• The transmission of electric current through this mode
is susceptible to security risks like cyber war fare

23. Biological impacts
• ELECTROHYPERSENSITIVITY
• ALTERED PHYSIOLOGY
• OXIDATIVE STRESS AND DAMAGED DNA

24. CONCLUSIONS
• This concept offers greater possibilities for
transmitting power with negligible losses and
ease of transmission than any invention or
discovery heretofore made. Dr. Neville of NASA
states “You don’t need cables, pipes, or copper
wires to receive power. We can send it to you like
a cell phone call – where you want it, when you
want it, in real time”. We can expect with
certitude that in next few years. Wonders will be
brought by its applications if all the conditions are
favourable.

25. References
• http://cleantechindia.wordpress.com/2014/2/8/indias-electricity-transmission-and-
distribution-losses
• Tesla, “ My inventions”, Ben Johnson , Ed,Austin , Hart Brothers,p.91,1982
• ] S. Sheik Mohammed, K. Ramasamy, T. Shanmuganantham Wireless Power
Transmission – A Next Generation Power Transmission System ©2010 International
Journal of Computer Applications (0975 – 8887) Volume 1 – No. 13
• Joshua Le-Wei Li- Wireless Power Transmission: State-of-the-Arts in Technologies
and Potential Applications Proceedings of the Asia-Pacific Microwave Conference
2011
• Andreev, A.D. Directed Energy Div., Raytheon Missile Syst., Albuquerque, NM, USA
Hendricks, K.J. Multicavity Magnetron With the “Rodded” Quasi-
MetamaterialCathodePlasma Science, IEEE Transactions on (Volume:41 , Issue:
3 ), Page(s):620 - 627, IEEE Nuclear and Plasma Sciences Society,IEEE

26. References
• Kumar, B.U, “Wireless power generation using rectenna”, Green Computing,
Communication and Conservation of Energy (ICGCE), 2013 International
Conference on, Page(s):330 – 334, IEEE[7] Bidkar, R ,” Space Based Solar Power
(SBSP): An emerging technology”, Power Electronics (IICPE), 2012 IEEE 5th India
International Conference onPage(s):1 – 4ISSN :2160-3162 ,Publisher- IEEE
• Bidkar,R ,” Space Based Solar Power (SBSP): An emerging technology”, Power
Electronics (IICPE), 2012 IEEE 5th India International Conference onPage(s):1 –
4ISSN :2160-3162 ,Publisher- IEEE
• W.C. Brown, J.R. Mims and N.I. Heenan, “An Experimental Microwave-Powered
Helicopter”, 965 IEEE International Convention Record, Vol. 13, Part 5, pp.225-235
• Wu, T.Y, “ Broadband microwave attenuation measurement standard in the
frequency range from 10 MHz to 26.5 GHz” Instrumentation and Measurement
Technology Conference, 2009. I2MTC '09. IEEE, Page(s):1620 – 1624, ISSN :1091-
5281,IEEE
• John M. Osepchuk, “Health and safety issues for microwave powertransmission”,
Solar Energy, vol. 56, 1996