A

Seminar Report Entitled on

““MMIICCRROOWWAAVVEE WWIIRREELLEESSSS PPOOWWEERR TTRRAANNSSMMIISSSSIIOONN””

INDEX

SR. NO. CHAPTER PAGE NO.

1 Introduction 1

2 Methods of Wireless Transmission of Electrical

Power

2.1 Induction 2

2.2 Electromagnetic Induction 2

2.3 Evanescent Wave Coupling 2

2.4 Electrodynamic Induction 2

2.5 Radio And Microwave 2

2.6 Electrostatic Induction 3

2.7 Component of WPT System 3

2.8 Types of WPT 4

3 Wireless Power Transmission Technology

3.1 Recent Researches In WPT 6

3.2 Depending Upon Distance Between

Transmitter And Receiver

3.2.1 Short Distance Induction 6

3.2.2 Moderate Distance Induction 7

3.2.3 Long Distance Induction 9

3.2.4 Efficiency 10

3.3 Current Technologies in the field of Wireless

Power Transmission

3.3.1 Microwave Transmitter 11

3.2.2 Use of Microwave Power Transmission 12

In SPS

3.4 Latest Inventions And Experiments

3.4.1 Witricity 13

3.4.2 Intel’s Demonstration 13

4 Applications

4.1 Need for Wireless Power Transmission 15

4.2 Advantages 16

4.3 Disadvantages 16

4.4 Biological aspects 16

5 Future aspects in wireless power transmission

5.1 Power Generating Solar Satellite 17

5.2 Third Generation Wireless Power 17

5.3 Conclusion 18

References 19

LIST OF TABLES

Sr. No. Name Page No.

2.1 Performance of Printed Rectenna 4

2.2 Rectenna Efficiency for various diodes 4

LIST OF FIGURES

Fig. No. Name Page No.

1.1 The 187 feet Wardenclyffe Tower 1

3.1 Block Diagram of WPT 5

3.2 A splash Mat 7

3.3 Curved coil Capacitive Plate 8

3.4 Resonant Inductive Coupling 9

3.5 SHARP Unmanned Plane 10

3.6 Microwave Transmitter 11

3.7 Microwave Power Transmission In SPS 12

3.8 Witricity 13

3.9 Experiment At Intel For WPT 14

3.10 Nevada Lightening Laboratory 14

4.1 Need for Wireless Transmission 15

4.2 Need For Home Appliances 15

5.1 Japan’s wireless power generation satellite 17

CHAPTER 1

INTRODUCTION

One of the major issue in power system is the losses occurs during the transmission and

distribution of electrical power. As the demand increases day by day, the power generation

increases and the power loss is also increased. The major amount of power loss occurs during

transmission and distribution. The percentage of loss of power during transmission and

distribution is approximated as 26%. The main reason for power loss during transmission and

distribution is the resistance of wires used for grid. The efficiency of power transmission can be

improved to certain level by using high strength composite overhead conductors and

underground cables thatuse high temperature super conductor. But, the transmission is still

inefficient. According to the World Resources Institute (WRI), India’s electricity grid has the

highest transmission and distribution losses in theworld – a whopping 27%. Numbers published

by various Indian government agencies put that number at 30%,40% and greater than 40%. This

is attributed to technical losses (grid’s inefficiencies) and theft. Any problem can be solved by

state of the art technology. The above discussed problem can be solvedby choose an alternative

option for power transmission which could provide much higher efficiency, low transmission

cost and avoid power theft. Microwave Power Transmission is one of the promising

technologiesand may be the righteous alternative for efficient power transmission.

fig.1.1.The 187 feet Wardenclyffe Tower

William C. Brown contributed much to the modern development of microwave power

transmission which dominates research and development of wireless transmission today. In the

early 1960s brown invented the rectenna which directly converts microwaves to DC current.

CHAPTER 2

METHODS OF WIRELESS TRANSMISSION OF

ELECTRICAL POWER

2.1 INDUCTION

The principle of mutual induction between two coils can be used for the transfer of

electrical power without any physical contact in between. The simplest example of how mutual

induction works is the transformer, where there is no physical contact between the primary and

the secondary coils. The transfer of energy takes place due to electromagnetic coupling between

the two coils.

2.2 ELECTROMAGNETIC TRANSMISSION

Electromagnetic waves can also be used to transfer power without wires. By converting

electricity into light, such as a laser beam, then firing this beam at a receiving target, such as a

solar cell on a small aircraft, power can be beamed to a single target. This is generally known as

“power beaming”.

2.3 EVANESCENT WAVE COUPLING

Researchers at MIT believe they have discovered a new way to wirelessly transfer power

using non-radioactive electromagnetic energy resonant tunnelling. Since the electromagnetic

waves would tunnel, they would not propagate through the air to be absorbed or wasted, and

would not disrupt electronic devices or cause physical injury like microwave or radio

transmission. Researchers anticipate up to 5 meters of range.

2.4 ELECTRODYNAMIC INDUCTION

Also known as "resonant inductive coupling" resolves the main problem associated with

non-resonant inductive coupling for wireless energy transfer; specifically, the dependence of

efficiency on transmission distance. When resonant coupling is used the transmitter and receiver

inductors are tuned to a mutual frequency and the drive current is modified from a sinusoidal to a

non-sinusoidal transient waveform.

2.5 RADIO AND MICROWAVE

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. A rectenna may be used to convert the microwave energy back into electricity.

Rectenna conversion efficiencies exceeding 95% have been realized.

2.6 ELECTROSTATIC INDUCTION

Also known as "capacitive coupling" is an electric field gradient or differential

capacitance between two elevated electrodes over a conducting ground plane for wireless energy

transmission involving high frequency alternating current potential differences transmitted

between two plates or nodes.

2.7 COMPONENTS OF WPT SYSTEM

The Primary components of Wireless Power Transmission are Microwave Generator,

Transmitting antenna and Receiving antenna (Rectenna). The components are described in this

chapter.

2.7.1 MICROWAVE GENERATOR

The microwave transmitting devices are classified as Microwave Vacuum Tubes

(magnetron, klystron, Travelling Wave Tube (TWT), and Microwave Power Module (MPM))

and Semiconductor Microwave transmitters (GaAs MESFET, GaN pHEMT, SiC MESFET,

AlGaN/GaN HFET, and InGaAS). Magnetron is widely used for experimentation of WPT.

The microwave transmission often uses 2.45GHz or 5.8GHz of ISM band. The other

choices of frequencies are 8.5 GHz, 10 GHz and 35 GHz. The highest efficiency over 90% is

achieved at 2.45 GHz among all the frequencies.

2.7.2 TRANSMITTING ANTENNA

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.

2.7.3 RECTENNA

The concept, the name “rectenna" and the rectenna was conceived by W.C. Brown of

Raytheon Companyin the early of 1960s [16]. The rectenna is a passive element consists of

antenna, rectifying circuit with a low pass filter between the antenna and rectifying diode. The

antenna used in rectenna may be dipole, Yagi –Uda,microstrip or parabolic dish antenna. The

patch dipole antenna achieved the highest efficiency among the all. The performance of various

printed rectenna is shown in TABLE 2.1.

TABLE 2.1 Performance of printed rectenna

Type of

Rectenna

Operating

Frequency

(GHz)

Measured

Peak

Conversion

Efficiency

(%)

Printed diploma 2.45 85

Circular Patch 2.45 81

Printed dual

Rhombic

5.6 78

Schottky barrier diodes (GaAs-W, Si, andGaAs) are usually used in the rectifying circuit

due to the faster reverse recovery time and much lower forward voltage drop and good RF

characteristics. The rectenna efficiency for various diodes at different frequency is shown in

TABLE 2.2

TABLE 2.2. Rectenna Efficiency for various diodes at different frequency

FREQ. GHz SCHOTTKEY

DIODE

MEASURED

EFFICIENCY

CALCULATED

EFFICIENCY

2.45 GaAs-W 92.5 90.5

5.8 Si 82 78.3

8.51 GaAs 62.5 66.2

2.8 TYPES OF WPT

2.8.1 NEAR-FIELD TECHNIQUES

Inductive Coupling

Resonant Inductive Coupling (RIC)

Air Ionization

2.8.2 FAR-FIELD TECHNIQUES

Microwave Power Transmission (MPT)

LASER power transmission

CHAPTER 3

WIRELESS POWER TRANSMISSION TECHNIQUES

William C. Brown, the pioneer in wireless power transmission technology, has designed,

developed a unit and demonstrated to show how power can be transferred through free space by

microwaves. The concept of Wireless Power Transmission System is explained with functional

block diagram shown in fig 3.1.

fig.3.1 Block diagram of WPT

In the transmission side, the microwave power source generates microwave power and

the output power is controlled by electronic control circuits. The wave guide ferrite circulator

which protects the microwave source from reflected power is connected with the microwave

power source through the Coax – Waveguide Adaptor. The tuner matches the impedance

between the transmitting antenna and the microwave source. The attenuated signals will be then

separated based on the direction of signal propagation by Directional Coupler. The transmitting

antenna radiates the power uniformly through free space to the rectenna.In the receiving side, a

rectenna receives the transmitted power and converts the microwave power into DC power. The

impedance matching circuit and filter is provided to setting the output impedance of a signal

source equal to the rectifying circuit. The rectifying circuit consists of Schottky barrier diodes

converts the received microwave power into DC power.

3.1 RECENT RESEARCHES IN WPT

Researchers have been going on in the field of using microwave power transfer and many

technologies are being developed around the globe.

3.1.1 ANTENNAS: -

In some MPT experiments in Japan, the phased array antenna was adopted to steer a

direction of the microwave beam.

3.1.2 TRANSMITTERS: -

Magnetron travelling wave tube amplifiers, klystron, semiconductor amplifiers.

3.2 DEPENDING ON DISTANCE BETWEEN THE TRANSMITTER AND RECEIVER

These techniques are briefly classified into three depending on the distance

between the transmitter and receiver. These are: Short range, Moderate range Long range.

3.2.1 SHORT DISTANCE INDUCTION

These methods can reach at most a few centimetres the action of an electrical transformer

is the simplest instance of wireless energy transfer. The primary and secondary circuits of a

transformer are electrically isolated from each other. The transfer of energy takes place by

electromagnetic coupling through a process known as mutual induction. (An added benefit is the

capability to step the primary voltage either up or down.) The electric toothbrush charger is an

example of how this principle can be used.

A toothbrush's daily exposure to water makes a traditional plug- in charger potentially

dangerous. Ordinary electrical connections could also allow water to seep into the toothbrush,

damaging its components. Because of this, most toothbrushes recharge through inductive

coupling. You can use the same principle to recharge several devices at once. For example, the

Splash power recharging mat and Edison Electric's Power desk both use coils to create a

magnetic field. Electronic devices use corresponding built- in or plug- in receivers to recharge

while resting on the mat. These receivers contain compatible coils and the circuitry necessary to

deliver electricity to devices' batteries

fig.3.2 A splash mat for simultaneous charging of electronics devices

3.2.2 MODERATE DISTANCE RESONANCE AND WIRELESS POWER

Household devices produce relatively small magnetic fields. For this reason, chargers

hold devices at the distance necessary to induce a current, which can only happen if the coils are

close together. A larger, stronger field could induce current from farther away, but the process

would be extremely inefficient. Since a magnetic field spreads in all directions, making a larger

one would waste a lot of energy. An efficient way to transfer power between coils separated by a

few meters is that we could extend the distance between the coils by adding resonance to the

equation. A good way to understand resonance is to think of it in terms of sound. An object's

physical structure -- like the size and shape of a trumpet determines the frequency at which it

naturally vibrates. This is its resonant frequency. It's easy to get objects to vibrate at their

resonant frequency and difficult to get them to vibrate at other frequencies. This is why playing a

trumpet can cause a nearby trumpet to begin to vibrate. Both trumpets have the same resonant

frequency. Induction can take place a little differently if the electromagnetic fields around the

coils resonate at the same frequency. The theory uses a curved coil of wire as an inductor. A

capacitance plate, which can hold a charge, attaches to each end of the coil. As electricity travels

through this coil, the coil begins to resonate. Its resonant frequency is a product of the inductance

of the coil and the capacitance of the plates.

fig.3.3 Curved Coil Capacitive Plate

Electricity travelling along an electromagnetic wave, can tunnel from one coil to the other

as long as they both have the same resonant frequency. In a short theoretical analysis they

demonstrate that by sending electromagnetic waves around in a highly angular waveguide,

evanescent waves are produced which carry no energy. An evanescent wave is near field

standing wave exhibiting exponential decay with distance. If a proper resonant waveguide is

brought near the transmitter, the evanescent waves can allow the energy to tunnel (specifically

evanescent wave coupling, the electromagnetic equivalent of tunnelling to the power drawing

waveguide, where they can be rectified into DC power. Since the electromagnetic waves would

tunnel, they would not propagate through the air to be absorbed or dissipated, and would not

disrupt electronic devices.

As long as both coils are out of range of one another, nothing will happen, since the fields

around the coils aren't strong enough to affect much around them. Similarly, if the two coils

resonate at different frequencies, nothing will happen. But if two resonating coils with the same

frequency get within a few meters of each other, streams of energy move from the transmitting

coil to the receiving coil. According to the theory, one coil can even send electricity to several

receiving coils, as long as they all resonate at the same frequency. The researchers have named

this non-radioactive energy transfer since it involves stationary fields around the coils rather than

fields that spread in all directions.

According to the theory, one coil can recharge any device that is in range, as long as the

coils have the same resonant frequency. "Resonant inductive coupling" has key implications in

solving the two main problems associated with non-resonant inductive coupling and

electromagnetic radiation, one of which is caused by the other; distance and efficiency.

fig.3.4 Resonant Inductive Coupling

Electromagnetic induction works on the principle of a primary coil generating a

predominantly magnetic field and a secondary coil being within that field so a current is induced

within its coils. This causes the relatively short range due to the amount of power required to

produce an electromagnetic field. Over greater distances the non-resonant induction method is

inefficient and wastes much of the transmitted energy just to increase range.

This is where the resonance comes in and helps efficiency dramatically by "tunnelling"

the magnetic field to a receiver coil that resonates at the same frequency. Unlike the multiple-

layer secondary of a non-resonant transformer, such receiving coils are single layer solenoids

with closely spaced capacitor plates on each end, which in combination allow the coil to be tuned

to the transmitter frequency thereby eliminating the wide energy wasting "wave problem" and

allowing the energy used to focus in on a specific frequency increasing the range.

3.2.3 LONG-DISTANCE WIRELESS POWER

Whether or not it incorporates resonance, induction generally sends power over relatively

short distances. But some plans for wireless power involve moving electricity over a span of

miles. A few proposals even involve sending power to the Earth from space. In the 1980s,

Canada's Communications Research Centre created a small airplane that could run off power

beamed from the Earth. The unmanned plane, called the Stationary High Altitude Relay Platform

(SHARP), was designed as a communications relay. Rather flying from point to point, the

SHARP could fly in circles two kilometres in diameter at an altitude of about 13 miles (21

kilometres). Most importantly, the aircraft could fly for months at a time.

fig.3.5 Sharp Unmanned Plane

The secret to the SHARP's long flight time was a large, ground-based microwave

transmitter. The SHARP's circular flight path kept it in range of this transmitter. A large, disc-

shaped rectifying antenna, or rectenna, just behind the plane's wings changed the microwave

energy from the transmitter into direct-current (DC) electricity.

Because of the microwaves' interaction with the rectenna, the SHARP had a constant

power supply as long as it was in range of a functioning microwave array. Rectifying antennae

are central to many wireless power transmission theories. They are usually made an array of

dipole antennae, which have positive and negative poles. These antennae connect to shottkey

diodes. Here's what happens:

1. Microwaves, which are part of the electromagnetic spectrum reach the dipole antennae.

2. The antennae collect the microwave energy and transmit it to the diodes.

3. The diodes act like switches that are open or closed as well as turnstiles the let electrons flow

in only one direction. They direct the electrons to the rectenna's circuitry.

4. The circuitry routes the electrons to the parts and systems that need them.

3.2.4 EFFICIENCY

The efficiency of wireless power is the ratio between power that reaches the receiver and

the power supplied to the transmitter. Researchers successfully demonstrated the ability to power

a 60 watt light bulb from a power source that was seven feet (2meters) away using resona ting

coils. This kind of setup could power or recharge all the devices in one room. Some

modifications would be necessary to send power over long distances, like the length of a building

or a city. Power transmission via radio waves can be made more direct ional, allowing longer

distance power beaming, with shorter wavelengths of electromagnetic radiation, typically in the

microwave range. A rectenna may be used to convert the microwave energy back into electricity.

Rectenna conversion efficiencies exceeding 95% have been realized. Wireless Power

Transmission (using microwaves) is well proven. Experiments in the tens of kilowatts have been

performed.

3.3 CURRENT TECHNOLOGIES IN THE FIELD OF WIRELESS POWER

TRANSMISSION

3.3.1 MICROWAVE TRANSMITTER

fig.3.6 Microwave Transmitter

The most current research and proposals use microwaves as the frequency range of choice

for transmission. At present an efficiency of 76% is possible using current technology for

microwave power transmission.

For transmission efficiency the waves must be focused so that all the energy transmitted

by the source is incident on the wave collection device. Higher frequencies are also impractical

because of the high cost of transmitters and the relative low efficiency of current optical and

infrared devices.

The most common transmitters for microwaves are the travelling wave tube (TWT),

klystron and magnetron. The TWT is far too expensive and power restrictive making it

impractical for the task of power transmission. The klystron has been the DC to microwave

converter of choice however it is also somewhat expensive. Many researchers are looking to use

magnetrons instead because they are cheap and efficient. Magnetron frequency output is not as

precisely controllable as the klystron or TWT but power transmission is more lenient to

frequency fluctuations than communication systems are. One of the more common proposals

would be for an array of magnetrons to be used as the transmitter. One of the main advantages to

using many smaller magnetrons as opposed to a few klystrons is that 300 W to 1kW magnetrons

are already mass produced for microwave ovens. The efficiency of magnetrons is inconsistently

reported.

3.3.2 USE OF MICROWAVE POWER TRANSMISSION IN SOLAR POWER

SATELLITES (SPS)

Solar power generating satellites launched into space and transmitting power to Earth

stations. This idea was first proposed in 1968 and all of the experiments have only been carried

out in terrestrial laboratories. The SPS satellites would be put in high earth orbit at

geosynchronous location. This would allow them to receive light 99% of the year. A large

rectenna array facility will be built on the Earth to collect the incoming microwaves. To maintain

a good lock on the rectenna the satellite will need to be built with a retrodirective transmitter

which locks on to a pilot beam emanated from the ground station.

fig.3.7 Microwave Power Transmission in SPS

Since most of the research is done in the 2.4 GHz to 5.8 GHz range there are some spectrum

regulatory issues to deal with. Also since the retro directive antenna system is unproven. There is

the health concern that the microwave beam could veer off target and microwave some

unsuspecting family. However, a Japanese government agency is planning to send up 10 to 100

kW low earth orbit satellite to prove its feasibility.

3.4 LATEST INVENTIONS AND EXPERIMENT

3.4.1. WITRICITY

The new technology called Witricity is based on using coupled resonant objects. Two

resonant objects of the same resonant frequency tend to exchange energy efficiently, while

interacting weakly with extraneous off-resonant objects.

fig.3.8 Witricity

A child on a swing is a good example of this. A swing is a type of mechanical resonance,

so only when the child pumps her legs at the natural frequency of the swing is she able to impart

substantial energy. The investigated design consists of two copper coils, each a self-resonant

system.

One of the coils, attached to the power source, is the sending unit. Instead of irradiating

the environment with electromagnetic waves, it fills the space around it with a non-radiative

magnetic field oscillating at MHz frequencies. The non-radiative field mediates the power

exchange with the other coil (the receiving unit), which is specially designed to resonate with the

field. The resonant nature of the process ensures the strong interaction between the sending unit

and the receiving unit, while the interaction with the rest of the environment is weak.

3.4.2 INTEL’S DEMONSTRATION

Intel demonstrated a captivating technology that has the potential to eliminate the need for

power cords, chargers or batteries. During the presentation at yesterday’s Intel Developer Forum

(IDF), the chip maker wirelessly powered a 60 watt light globe from three feet away with 75

percent efficiency. The technology works by creating resonance between two magnetic fields,

known as a “resonant induction” phenomenon. Intel hopes to one day use the technology to

power laptops and other portable devices, either directly via a transmitter or by

charging internal super capacitors which can be rapidly recharged. The research project at Intel,

led by Joshua R. Smith aims to build upon this work.

fig.3.9 Experiment at Intel for WPT

Lightning Lab accidentally transferred a large amount of energy while testing a high-frequency

transformer.

The Nevada Lightning Laboratory noticed another transformer across the lab beginning to

“smoke profusely” during the test. They found the transformer was physically disconnected from

its power source and set out to try and learn what had happened.

They discovered that even widely spaced coils were capable of wirelessly transmitting

large amounts of power and to test it out, they rigged up a board of twenty 40W light globes with

the transmitter and receiver 5 meters (16.4ft) apart. The major drawback, as is always the case

with wireless power transmission, is the amount of energy lost during the process. The

transmitting coil was operating at 3.6KW for the receiver to capture the 800W, which is quite

inefficient.

Fig.3.10 The Nevada Lightening Laboratory

CHAPTER 4

APPLICATIONS

4.1 NEED FOR WIRELESS POWER TRANSMISSION

Wireless transmission is employed in cases where instantaneous or continuous energy transfer is

needed, but interconnecting wires are inconvenient, hazardous, or impossible.

fig.4.1 Need for Wireless Transmission

Number of household points receives electricity at the same frequency using single

transmitting coil as long as they all are at resonance. So this setup could recharge all the devices

in a room at once.

fig.4.2 Need for home appliances

4.2 ADVANTAGES

Wireless Power Transmission system would completely eliminates the existing high-

tension power transmission line cables, towers and sub stations between the generating station

and consumers and facilitates the interconnection of electrical generation plants on a global

scale. It has more freedom of choice of both receiver and transmitters.

Even mobile transmitters and receivers can be chosen for the WPT system. The cost of

transmission and distribution become less and the cost of electrical energy for the consumer also

would be reduced. The power could be transmitted to the places where the wired transmission is

not possible. Loss of transmission is negligible level in the Wireless Power Transmission;

therefore, the efficiency of this method is very much higher than the wired transmission. Power

is available at the rectenna as long as the WPT is operating. The power failure due to short

circuit and fault on cables would never exist in the transmission and power theft would be not

possible at all.

4.3 DISADVANTAGES

The Capital Cost for practical implementation of WPT seems to be very high and the other

disadvantage of the concept is interference of microwave with present communication systems.

Health hazards may occur.

4.4 BIOLOGICAL IMPACTS

Common beliefs fear the effect of microwave radiation. But the studies in this domain

repeatedly proves that the microwave radiation level would be never higher than the dose

received while opening the microwave oven door, meaning it is slightly higher.

CHAPTER 5

FUTURE ASPECTS IN WIRELESS POWER TRANSMISSION

5.1 POWER-GENERATING SOLAR SATELLITE INHABITAT

fig.5.1 Japan’s Wireless Power Generation Solar Satellite

Japan wants to power up three million houses with wireless energy from space. They have

serious plans to send a solar-panel-equipped satellite into space that could wirelessly beam a gig

watt-strong stream of power down to earth.

A small test model is scheduled for launch in 2015. To iron out all the kinks and get a

fully functional system set up is estimated to take three decades. A major kink, presumably, is

coping with the possible dangers when a 1-gigawatt microwave beam aimed at a small spot on

Earth misses its target. The $21 billion project just received major backing from Mitsubishi and

designer IHI (in addition to research teams from 14 other countries).

5.2 THIRD-GENERATION WIRELESS POWER

Power by Proxi has developed a 3G wireless power delivery system. Earlier generations of

wireless power technology were based on split transformers consisting of two halves: an input

side (primary) and an output side (secondary). Electrical energy applied to the primary is

converted to an electromagnetic field that induces a current in the secondary, which passes the

energy to a load. The essential difference between earlier generations of wireless power solutions

and the one developed by Power by Proxi is that the Power by Proxi system offers high

efficiency levels in relatively loose coupling arrangements across an air gap or through any

nonmetallic substrate.

5.3 CONCLUSION:

The concept of Microwave Power transmission (MPT) and Wireless Power Transmission

system is presented. The technological developments in Wireless Power Transmission (WPT),

the advantages, disadvantages, biological impacts and applications of WPT are also discussed.

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 wrought by its

applications if all the conditions are favourable.

REFERENCES

1. http://cleantechindia.wordpress.com/2008/07/16/indiaselectricity-transmission-and-

distribution- losses/

2. Nikola Tesla, My Inventions, Ben Johnston, Ed., Austin, Hart Brothers, p. 91, 1982.

3. 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).

4. W.C. Brown, J.R. Mims and N.I. Heenan, “An Experimental Microwave-Powered

Helicopter”, 965 IEEE International Conventions Record, Vol. 13, Part 5, pp.225-235.

5. 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).

6. http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1132833.

7. POINT-TO-POINT WIRELESS POWER TRANSPORTATION IN REUNION ISLAND

48th International Astronautical Congress, Turin, Italy, 6-10 October 1997 - IAF-97-

R.4.08 J. D. Lan Sun Luk, A. Celeste, P. Romanacce, L. Chane Kuang Sang, J.C. Gatina

- University of La Réunion - Faculty of Science and Technology.