This document discusses wireless power transmission (WPT) and compares microwave and laser transmission methods. It describes how a rectenna works to receive microwaves with 85% efficiency within 5km. Solar power satellites that transmit power via microwaves from space are also discussed, including their advantages over earth-based solar like constant sunlight. Current development of a low-cost Japanese demonstration project by 2025 and potential applications of WPT like electric vehicles are mentioned.

1. Submitted by:
Shuvo Saha Roy
Dept: EEE,KUET
Roll: 1003008
Year:4th Term:1st
Date:19-08-2014

2. Overview
 Wireless power transmission(WPT)
 Why WPT
 Microwave Transmission
 Microwave vs. laser transmission
 Rectenna
 Solar power Satellite
 Current Developments
 Advantages of WPT
 Disadvantages of WPT
 Applications

8. Microwave vs. Laser Transmission
Microwave Transmission
 More developed
 High efficiency up to
85%
 Beams are far below the
lethal levels of
concentration even for a
prolonged exposure
 Causes interference with
satellite communication
industry
Laser Transmission
 Recently developed
solid state lasers allow
efficient transfer of
power
 Range of 10% to 20%
efficiency within a
few years
 Conform to limits on
eye and skin damages

9. Rectenna
 An antenna comprising a mesh of dipoles and
diodes for absorbing microwave energy from a
transmitter and converting it into electric
power
 Microwaves are received with about 85%
efficiency
 Around 5km across (3.1 miles)
 95% of the beam will fall on the rectenna

11. Solar power satellite(SPS)
 1968’s idea for Solar power Satellites proposed by Peter
Glaser
 Would use microwaves to transmit power to earth from
space
 To efficiently make use of renewable energy i.e. solar
energy
 Solar powered satellites are placed in geostationary orbits
 Solar power from the satellite is sent to earth using a
microwave transmitter
 Received at a “Rectenna” located on Earth

12. Architecture of Solar power
Satellite(SPS)

14. Advantages over Earth based Solar
Power
 More intense sunlight
 In geosynchronous orbit, 36,000 km (22,369 miles) an SPS
would be illuminated over 99% of the time
 No need for costly storage devices for when the sun is not
in view
 Waste heat is radiated back into space
 Power can be beamed to the location where it is needed,
don’t have to invest in as large a grid
 No air or water pollution is created during generation

15. Current Development
 Project in development in Japan
 Goal is to build a low cost
demonstration model by 2025
 8 Countries along the equator
have agreed to be the site of a
rectenna
 10MW satellite delivering
microwave power
 Will not be in geosynchronous
orbit , instead lower orbit 1100 km
(683 miles)
 Much cheaper to put a satellite in
a low orbit
 200 seconds of power on each
pass over rectenna

16. Advantages of WPT
 Efficient
 Easy
 The power could be transmitted to the remote places where the wired
transmission is not possible
 Need for grid, high tension transmission lines, substations are eliminated
 Low maintenance cost
 Power theft would be not possible at all
 The power failure due to short circuit and fault on cables would never
exist in the transmission.
 The cost of transmission and distribution would become less
 The cost of electrical energy for the consumer would be reduced also
 Wireless charging would also possible
 Vehicles would be driven using WPT, no need of fuel.

17. Disadvantages of WPT
 Cost for practical implementation of WPT seems
to be very high.
 The other disadvantage of the concept is
interference of microwave with present
communication systems.

18. Applications of WPT
 Solar Power Satellites (SPS)
 Moving targets such as fuel free airplanes, fuel
free electric vehicles, moving robots and fuel free
rockets
 Ubiquitous Power Source (or) Wireless Power
Source
 Wireless sensors
 RF Power Adaptive Rectifying Circuits (PARC)

20. Thank You All