WIRELESS POWER TRANSMISSION
USING MICROWAVES AND SOLAR
INSTITUTE OF TECHNICAL EDUCATION &
PROFESSOR MIHIR NARAYAN MOHANTY
HISTORY OF WIRELESS POWER TRANSMISSION
METHODS OF SPACE BASED WPT
RF-DC CONVERSION USING RECTENNA
CONCEPT OF SOLAR POWER SATELLITE
CONCLUSION AND DISCUSSION
WHY WE NEED WIRELESS POWER TRANSMISSION?
We are in an age of serious energy crisis and resource crunch.
Wireless power transmission from space using Solar
Wireless energy transmission to distant remote islands.
Powering aerial vehicles from ground.
HISTORY OF WPT
Nicola Tesla considered as the
Father of WPT.
Tesla applied the principle of
resonance to transfer power wirelessly.
William Brown of Raytheon
company used MWPT for wireless
In 1975 a grand MWPT
experiment occurred at
NASA Jet Propulsion
It generated 37 KW of
power that was sent to a
rectenna system , located
one mile away, which
collected and converted
84% of the energy to DC. www.mwrf.com
METHODS OF SPACE BASED WPT
Far Term Space Systems to beam power to Earth
Radio-Wave WPT System
In case of light-wave system we use laser beam for
wireless power transmission.
In case of radio-wave power transmission systems we use
microwaves for wireless power transmission.
ATTRIBUTE MWPT LASER
INTERFERENCE Radio frequency
None except astronomical
APERTURE SIZE Large, so system is very
ATTENUATION Penetrates clouds and
Stopped by clouds
EFFICIENCY (SPACE) HIGH IMPROVING
EFFICIENCY (GROUND) HIGH IMPROVING
SAFETY Keep aircraft out of beam Safe
PERCEPTION Public fears of “cooking” Government fears of
WPT USING MICROWAVES
Typical WPT uses point-to-point power transmission.
Lower frequency electromagnetic waves suffer from
directivity issues and less efficiency.
The Rayleigh criterion dictates that any radio wave,
microwave or laser beam will spread and become weaker
and diffuse over distance;
Power transmission via radio waves can be made more
directional, allowing longer distance power beaming,
with shorter wavelengths of electromagnetic radiation,
typically in the microwave range.
WPT USING MICROWAVES(Continued)
Microwaves have frequencies between 300 MHz
(0.3 GHz) and 300 GHz (1m to 1mm).
The atmosphere is transparent at longer
wavelengths (e.g. 100 MHz), opaque at shorter
wavelengths (e.g. 400 GHz), but becomes
transparent again when you go up to 500 THz
BUILDING BLOCKS OF MWPT SYSTEM
A converter for converting DC to Microwave
Antenna for transmission of the generated
A rectifying antenna (RECTENNA) for receiving the
microwave beam and converting back into DC.
DC-RF (MICROWAVE GENERATOR)
The DC-RF conversion is done , using MAGNETRONS.
RECTENNA- Rectifying Antenna
Invented in 1964 and patented in 1969 by William C. Brown.
Its a special type of antenna used to convert microwave energy
The simplest crystal radio receiver, employing an antenna and
a demodulating diode (rectifier), is actually a rectenna -
although it discards the DC component
A simple rectenna element consists of a dipole antenna with
an RF diode connected across the dipole elements.
The diode rectifies the AC current induced in the antenna by
the microwaves, to produce DC power, which powers a load
connected across the diode.
• The diagram
shows a micro
array of many
SOLAR POWER SATELLITE
A CONCEPTUAL VIEW OF THE SYSTEM
The effective aperture size of Tx
can found out using the formula:
Assuming that transmitter
aperture efficiency is 80%, the
actual physical size of Tx is
It is composed of pilot signal receiving antennas
followed by detectors finding out the location of the
rectenna on the earth, power transmission antenna
The pilot signal frequency and a frequency for the
energy transmission are different from each other
( otherwise they will interfere each other).
Pilot signal makes it possible to find out the accurate
direction of a specified rectenna.
GROUND RECTENNA FOR SPS SYSTEM
NEEP602 Course Notes (Fall 1997) Resources from Space
Received power at rectenna, given by Friis
where Gt and Gr are the antenna gains (with respect to
an isotropic radiator) of the transmitting and receiving
antennas respectively, and R is the distance between the
TEST RESULT (R=225Km,Pt=1kw)
Gr f(GHz) Gt Pr(microwatt)
40 dB 5.8 20dB 0.3347
5.8 30dB 3.3466
10 20dB 0.1126
10 30dB 1.1258
50dB 5.8 20dB 3.346
5.8 30dB 33.4660
10 20dB 1.125
10 30dB 11.2580
The system efficiency is very low to be used for
practical purpose with current technology.
Emergence of META MATERIALS may change the
scenario in future.
Metamaterial antennas use metamaterials to
increase performance of miniaturized (electrically
small) antenna systems.
1. Corey Bergsrud, Sima Noghanian, Jeremy Straub, David
whalen, Ronald Fevig “ORBIT-TO-
GROUND WIRELESS POWER TRANSFER TEST
MISSION”, 2013 IEEE
2. Syed Atif Adnan, Muhammad Inam Abbasi, Farukh
“WIRELESS POWER TRANSFER USING MICROWAVES
AT 2.45 GHz ISM BAND”, proceedings of international
Bhurban Conference on applied science and technology,
3. T.S. Hasaramani
“WIRELESS POWER TRANSFER FOR SOLAR POWER
SATELLITE” , AKGEC journal of technology, vol .1 , no.2