In the near future due to extensive use of energy, limited supply of resources and the pollution in environment from present resources e.g. (wood, coal, fossil fuel) etc, alternative sources of energy and new ways to generate energy which are efficient, cost effective and produce minimum losses are of great concern. Wireless electricity (Power) transmission (WET) has become a focal point as research point of view and nowadays lies at top 10 future hot burning technologies that are under research these days. This paper presents the concept of transmitting power wirelessly to reduce transmission and distribution losses. The wired distribution losses are 70 - 75% efficient. We cannot imagine the world without electric power which is efficient, cost effective and produce minimum losses is of great concern.This paper tells us the benefits of using WET technology specially by using Solar based Power satellites (SBPS) and also focuses that how we make electric system cost effective, optimized and well organized. Solar Power Satellite (SPS) is an energy system which collects solar energy in space and transmits it to the ground. It has been believed as a promising infrastructure to resolve global environmental and energy problems for human beings. Microwave power transmission has been investigated and demonstrated for more than 40 years, but still requires further research regarding high-efficiency power conversion and high-accuracy beam control for SPS application. Moreover, attempts are made to highlight future issues so as to index some emerging solutions.

1. Md Saquib Maqsood
ID No: RA1412011010001
M.Tech (PED)
SRM University, Chennai

2. INTRODUCTION
• Present electricity generation system is not very efficient in
terms of energy transfer.
• 20 to 30% energy is lost during the distribution of the
electricity.
• Scientists are working on the projects to improve the
ultimate electricity supply.
• Looking for alternate and efficient technologies to provide
100% electricity transfer.
• Wireless transmission of electricity is also on move.

3. Wireless Electricity Transmission (WET)
Takes place in any type of system in which electrical current is
conveyed from a power source to an electrical load.
No usage of any type of wiring to connect the system to a
source of power.
Transmits electricity with the help of microwaves.
Three approaches which can be developed.

4. Continued…
1. Short range (Induction)
o Ranges few centimetres e.g. transformer in which transfer
takes place due to mutual induction.
2. Moderate range (Adaptive Inductive Coupling)
o AIC wireless power transfer technology can be used to charge
the electronic objects automatically.
o Works on the principle of using coupled resonant objects for
the transference of electricity to objects without the use of
any wire.

5. 1. Power from mains to antenna.
2. Antenna resonates at a frequency of about 10MHz, producing electromagnetic waves
3. Tails’ of energy from antenna ‘tunnel’ up to 2m .
4. Electricity picked up by laptop’s antenna, which must also be resonating at 10MHz.
5. Energy not transferred to laptop re-absorbed by source antenna.
Continued…

6. 3. Long range
o Moving electricity over a span of miles.
o Long distance wireless power is the technology of sending
power to earth.
o Many new techniques but we use only two here.
 By using Solar Power Satellite (SPS)
 By using WET Technology (Without SPS)

7. By using Solar Power Satellite (SPS)
o Satellite converts the sunlight into energy; this energy is
composed of microwaves.
o Microwave signals are transmitted to an antenna on
ground/Main grid station (MGS).
o From MGS these waves are transferred to BGS (Base grid
station) so called rectenna which convert microwaves into
DC electricity.

9. Without using SPS
o Produce electricity at MGS by (hydropower, Thermal ,Wind,
Solar ) and convert this electricity into microwaves by using
Microwave generator.
o Transfer it to base grid station (BGS) so called RECTENNA
through transmitting Antennas and from here electricity is
transmitted to home wirelessly.
o There will be energy receiver box or energy router in each
home.
o The information of the electricity or power required for
each home will be available with the grid station.

10. Component detail of WET using SPS system
 Microwaves
 Solar Power Satellites
 Microwave Generator
 Transmitting antenna
 Rectennas

11. Microwaves
• Wavelengths- 1 meter to 1 milimeter
• Frequency- 300 MHz and 300 GHz
• For wireless power transfer- high power microwaves
1-10GHz radio-waves.
• Used for point-to-point communication.
• This allows nearby microwave equipment to use the same
frequencies without interfering with each other, as lower
frequency radio waves do.

12. Solar Power Satellites
o Concept of collecting solar power in space for use on Earth. It
has been in research since the early 1970s.
o Mainly consists of three segments.
 Solar energy collector
 DC to microwave converter (Microwave tube system and /semiconductor
system).
 Transmitting Antenna

13. • Tubes such as Magnetron and Klystron have been proposed
for the SPS.
• The power conversion efficiency is reasonably high more
than 70 % at low cost.
Microwave Generator

14. • Most popular type of transmitting antenna- Slotted wave
guide antenna, micro strip patch antenna, and parabolic
dish antenna
• The slotted waveguide antenna - high aperture efficiency
(> 95%) and high power handling capability.
• Assembled by a number of array antenna panels.
• To form a microwave beam precisely focused at the ground
station, the phase of microwave from each panel needs to
be adjusted between the panels.
Transmitting antenna

15. Rectenna
• Rectifying antenna- directly convert microwave energy into DC
electricity.
• A simple rectenna element consists of a dipole antenna with a
Schottky diode placed across the dipole elements.
• Schottky diode- low forward bias volt.(< 0.6V) , faster , low
noise index, less power consumption.
• In laboratory environments, efficiencies of over 85% have been
observed.
• The efficiency of first Rectenna in 1963 was 50% at output 4W
DC.

16.  LPF is required to suppress harmonics to improve system performance and
prevent harmonics interference.
 Input filter also transforms the input impedance of the antenna to the
input impedance of the rectifier.
 The output filter is used to effectively block the RF energy and to pass the
DC power to a load or battery.
 The chip capacitor is also used to maximize the diode's conversion
efficiency.
 Inductance tunes the capacitance reactance of the diode. Its resonance is
needed to maximize the diode efficiency.

18. • First Ground-to-Ground
MPT Experiment in 1975
in US using JPL 26m dish
antenna and 3.4 m x 7.2
m rectenna located 1
mile apart from the
transmitter.
• Microwave of 2.388GHz
and 450 kW transmitted
from klystron and the
achieved rectified DC
power was 30 kW DC
with 82.5% rectifying
efficiency.

19. • MINIX rocket experiment in
1983 by Japanese scientists
carried out in space
• In the MINIX experiment, they
used cooker type 800W-
2.45GHz magnetron for
microwave transmitter.

20. • Currently Japanese scientists are set to test the largest wireless
electricity transmission ever attempted.
• The test is designed to transfer about 1200 watts of power at a range of
100 feet (could reach 300 feet)
• SPS Project is 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.

21. Advantages
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.
Microwaves (electricity) are more environments friendly. It
does not involve emission of carbon gases.
Zero fuel cost.

22. Conclusions
 More reliable than ground based solar power.
 Fossil fuel electric power plants generate greenhouse gases
which are responsible for global warming. WET can overcome
these problems well.
 In order for SPS to become a reality it several things have to
happen:
 Government support
 Cheaper launch prices
 Involvement of the private sector