PRESENTED BYFAISAL P.M13031281

WIRELESS CHARGING OF MOBILES USING MICRO WAVES

INTRODUCTION

A new proposal has made recharging of the mobile phones is done

automatically as you talk in your mobile phone!

The recharging of the mobile phones is independent of their manufacturer and

battery make.

The microwave signal is transmitted from the transmitter along with the

message signal using special kind of antennas called slotted wave guide

antenna at a frequency is 2.45 GHz.

OBJECTIVE

The main objective of this current proposal is to make the recharging of Mobile phones independent of their manufacturer and battery.

A rectenna & a filter is added to the ordinary mobiles during manufacturing time….

Thus the more you talk, the more is your mobile phone charged!!!

WHAT IS “SPECTRUM” ???

when white light is shone through a prism it is separated out into all the colors of the rainbow, this is the visible spectrum. So white light is a mixture of all colors.

The visible spectrum is just one small part of the electromagnetic spectrum.

The “ electromagnetic spectrum ‘’ of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object.

The types of electromagnetic radiation are broadly classified into the following classes :

1. Gamma radiation 2. X-ray radiation 3. Ultraviolet radiation 4. Visible radiation 5. Infrared radiation 6. Microwave radiation 7. Radio wave radiation

MICROWAVE REGION

Microwave wavelength range approximately from 1mm (thickness of pencil lead) to 30cm (about 12 inches).

The microwave region in electromagnetic spectrum ranges from

0.3cm to 300cm.

Microwave region give the information about the temperature of the object that emitted microwaves.

WHY WIRELESS CHARGING USING MICROWAVES ?????

Microwaves are good for transmitting information from one place to another ( because it penetrate haze , light rain , snow , clouds etc…).

It has shorter wavelength than remote sensing.

Microwave radiation are considered harmless

except for people with pace makers.

FREQUENCY SELECTION

The frequency selection is another

important aspect in transmission. Here we

have selected the license free 2.45 GHz

ISM(Industrial, Scientific and Medical)

band for this purpose.

Here we are going to use the S BAND of

the Microwave spectrum.

TRANSMITTER DESIGN

MAGNETRON

The MAGNETRON is a self-

contained microwave oscillator that

operates differently from the linear-

beam tubes.

Cross field and magnetic field are

used to produce high-power output.

ELECTRON BEAM ENERGY

MICROWAVE ENERGY

SLOTTED WAVEGUIDE ANTENNA

It is used as ideal power transmitter (because of its high aperture efficiency >95%) .

High impedance matching

It has 64 slots of power uniformly through free space to the RECTENNA.

The slotted waveguide transmits its energy using horizontal polarization, the best type for distanace transmission.

RECEIVER DESIGN The basic addition to a mobile phone is to be RECTENNA.

RECTENNA is a rectifying antenna, a special type of antenna that is used to convert microwave energy into direct current electricity.

Its elements are usually arranged in a mesh pattern .

Antenna is to receive the microwave signal and it just feed the signal to rectifier . Rectifier is to convert the microwave energy to electricity.

SENSOR CIRCUITRY

The sensor circuitry is a simple circuit, which detects if the mobile phone receives any message signal.

The operating frequency of the mobile phone is 900MHz or 1800MHz for communication.

LM2907-a simple F to V converter used as it operates between this specified range .

To trigger the rectenna circuit to ON and the mobile begins to charge using the microwave power automatically.

BLOCK DIAGRAM

The whole setup looks like this :

PRINCIPLE OF OPERATION

The microwave signal is transmitted along with message signal using slotted wave guide antenna

The sensor search for the mobile signal , in addition it has a “RECTENNA”.

Rectenna receives the transmitted power and converts the microwave power to DC power.

IMPLEMENTATIONS

Recently NOKIA has launched this

wireless charging technology in its new

recent mobile model “ NOKIA LUMIA

1020”.

Energy efficient chargers of all size and

shape to match the phone.

ADVANTAGES

One can carry their mobile phones any place even to a

remote village.

The use of wired chargers are eliminated.

The phone can be charged at any place and any time.

Electricity can be saved.

The more you talk the more you get charged.

DISADVANTAGES

Network traffic may cause problem in charging.

Rate of charging is of minute range .

Charging depends on network coverage.

REFERENCE

[1] HAGERTY,J.A., Nonlinear Circuits and Antennas for Microwave Energy Conversion”2009,

[2] SEDRA, A.S. and Smith K.G, “Microelectronic Circuits”, 5th

Edition, 2004

[3] www.nokialumia.com

[4] www.wikipedia.org

[5] http://en.wikipedia.org/wiki/Rectenna

[6] http://www.seminarsonly.com- Electronics Topics Retrieved