Reason for WPT
Components of WPT
Advantages and Disadvantages
WHAT IS WPT?
Wireless power transmission is a concept of transmitting
power without using wires.
The power transmission is based on microwaves from one
place to another in order to reduce transmission and
REASONS FOR WPT
Wireless transmission is useful in cases where
interconnecting wires are inconvenient, hazardous,
The losses occur during the
transmission and distribution of
The percentage of loss is 26%.
• Experiments performed between 1888 and 1907 by Nikola
• Started efforts on wireless transmission at 1891 in his
“experimental station” at Colorado
• He lighted a small incandescent lamp by
means of a resonant circuit grounded on one
• William C. Brown, the pioneer in wireless
power transmission technology
• The idea of Tesla is taken in to research after
100 years by a team led by Marin Soljacic from MIT.
COMPONENTS OF WPT
• The microwave transmitting devices are classified as
Microwave Vacuum Tubes, Microwave Power Module
(MPM) and Semiconductor Microwave transmitters.
• Magnetron is widely used for experimentation of WPT.
• The highest efficiency over 90% is achieved at 2.45 GHz
among all the frequencies.
• The slotted wave guide antenna, microstrip patch
antenna, and parabolic dish antenna are the most
popular type of transmitting antenna.
• The slotted waveguide antenna is ideal for power
transmission because of its high aperture efficiency
(> 95%) and high power handling capability.
• It was first conceived by W.C. Brown in the early of
• The rectenna is a passive element consists of
antenna, rectifying circuit with a low pass filter
Functional block diagram of WPT system
ON FREE SPACE
SCHOTTKY BARRIER DIODE RECEIVING
The efficiency of wireless power is the ratio
between power that reaches the receiver and the
power supplied to the transmitter.
A rectenna may be used to convert the microwave
energy back into electricity.
Rectenna conversion efficiencies exceeding 95%
have been realized.
Eliminates the high-tension power transmission line
cables, towers and sub stations
cost of transmission and distribution become less.
No power failure and power theft.
Safer by eliminating the sparking hazard.
The capital cost for practical implementation of WPT seems
to be very high.
Interference of microwave with present communication
Common beliefs fear the effect of microwave
But the radiation level is less than radiation from
microwave oven and higher than cellular phone.
Thus public exposure to WPT fields would also be
below existing safety guidelines.
Interferences to Existent Wireless System
Safety on Ground
Interaction with Atmosphere
Interaction with Space Plasmas
APPLICATIONS OF WPT
I. Wireless Power Transmission for Electric
II. Wireless Power Transmission for Mobile
WPT emerges out as the best alternative for efficient power
transmission despite its few drawbacks such as very high
WPT has very high efficiency as the loss during power
transmission is nearly negligible and it acts as boon for the
people of those areas where wired transmission is not
The power failure due to short circuit and electric faults
would not possible at all.
 Nikola Tesla, My Inventions, Ben Johnston, Ed., Austin, Hart
Brothers, p. 91,1982.
 Nikola Tesla, “The Transmission of Electrical Energy Without
Wires as a Means for Furthering Peace,” Electrical World and
Engineer. Jan. 7, p. 21, 1905.
 The Electrician (London), 1904).
 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.
 Brown., W. C. (September 1984). "The History of Power
Transmission by Radio Waves". Microwave Theory and Techniques, IEEE Transactions
on (Volume: 32, Issue: 9 On page(s): 1230- 1242 + ISSN: 0018-9480).