PRESENTED BYZEBA TABASSUMSARA JABEEN ECE lll YEARSHADAN WOMENS COLLEGE OF ENGINERING AND TECHNOLOGY

ContentsIntroduction

Transmitter design

Receiver design

Rectification antenna

Schottky diode

Sensor circuitry

Advantages and Disadvantages

Conclusion

Future scope

References

INTRODUCTIONAlways the recharging of mobile phone batteries

has always been a problem for us. 

This problem will be solved after our proposal………!!!!!!!! 

 In this paper a new proposal has been made so as to make the recharging of the mobile phones is done automatically as you talk in your mobile phone!

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

Thus the more you talk, the more is your mobile phone charged!!!!!!! This is new isn’t?!! 

What Is Microwaves?????Microwaves are good for transmitting

information from one place to another because microwave energy can penetrate haze, light rain and snow, clouds, and smoke.

Shorter microwaves are used in remote sensing.

These microwaves are used for radar like the Doppler radar used in weather forecasts 

Microwaves> Frequency Range: 3GHZ to 300GHZ

> Remort Sensing.

> Communication Industry.

>2.45GHZ ISM Band.

TRANSMITTER DESIGN

The MAGNETRON is a self-contained microwave oscillator that operates differently from the linear-beam tubes, such as the TWT and the klystron.

——Magnetron is used to produce high-power output required in radar and communications equipment 

—Microwaves used in mobile communication are also produced by similar Oscillators 

Magnetron - Construction

SLOTTED WAVEGUIDE ANTENNA

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

It has high power handling capacity .

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

PRINCEPLE OF OPREATIONAn additional feature to the mobile is RECTENNA.

RECTENNA Rectification + Antenna

Transmitting station with the microwave

transmitter

sensor

Rectenna

RFcable

circulator

waveguide

Slotted waveguideAntenna

mobile signal

The basic addition to the mobile phone is going to be the rectenna. 

 A rectenna is a rectifying antenna, a special type of

antenna that is used to directly convert microwave energy into DC electricity.

 —A simple rectenna can be constructed from a

schottky diode placed between antenna dipoles.

—The diode rectifies the current induced in the antenna by the microwaves. 

—Rectenae are highly efficient at converting microwave energy to electricity

RECEIVER DESIGN

WHAT’S RECTANNAE???What’s rectannae you are confused…….it’s

nothing but the combination of  rectifier and antenna.

  Antenna is to receive the microwave signal and it just feed the signal to  rectifier . 

Rectifier is to convert the AC signal to PULSATING DC signal. 

Process of Rectification

Comprises of a dipoles and diodes.

Usually its elements are arranged in the mesh pattern.

Directly converts the microwave signal into DC power.

The efficiency is up to 90% in laboratory environments.

Schottky diodeA Schottky barrier diode -- majority carrier device

Common diode -- minority carrier device.

Its reverse recovery time Trr is very short and shorter than 10 nS.

The forward voltage bias of the Schottky barrier diode is under 0.6V.

This is a comparatively ideal diode, such as for a 1 ampere limit

current PN interface.

P=0.6*1=0.6W Schottky diode P=1.1*1=1.1W common diode

Power comparison between common diode and Schottky diode

Sensor circuitry The sensor circuitry is a simple circuit, which detects if the mobile

phone receives any message signal.

In India the operating frequency of the mobile phone operators is

generally 900MHz or 1800MHz for the GSM system for mobile

communication.

A simple yet powerful F to V converter is LM2907.

ADVANTAGESUse of separate chargers is eliminated.Electricity is savedThe phone can be charged anywhere anytime. Wireless energy transfer can potentially recharge

the mobile phones without chords. Only one microwave transmitter can serve to all the

service providers in that area.The need of different types of chargers by different

manufacturers is totally eliminated.

DISADVANTAGESThe transmitter and receiver also should be

very powerful devices as the distance increases.

Slower Charging.

Wireless transmission of the energy causes some drastic effects to human body, because of its radiation.

More costly.

APPLICATIONS

WIRELESS HOME

MOPAR(WIRELESS CHARGING PAD)

MOJO

Conclusion

This novel idea minimises the tension of charging your mobile phones regularly. 

—No necessity of Chargers accompanying the mobile phone 

Efficient use of energy transmitted in the form of microwaves.

Future scope The wireless charging can even be done using the data exchange as

now only its only been implemented for voice calls.

With the advent of nanotechnology and MEMS the size of these

rectennas can be brought down to molecular level. It has been

theorized that similar devices, scaled down to the proportions used in

nanotechnology, could be used to convert light into electricity at

much greater efficiencies than what is currently possible with solar

cells. This type of device is called an optical rectenna.

Reference1. Tae-Whan yoo and Kai Chang, “Theoretical and Experimental

Development of 10 and 35 GHz rectennas” IEEE Transaction on

Microwave Theory and Techniques, vol. 40. No.6. June. 1992.

2. 5 Hawkins, Joe, et al, “ Wireless Space Power Experiment,” in

proceedings of the 9th summer Conference of NASA/USRA Advanced

Design Program and Advanced Space Design Program, June 14-18,

1993.

3. MW Medley Jr and MW Medley, ‘Microwave and RF circuits: analysis,

synthesis and design’, Artech House, Norwood, MA, 1993.

4. Falone, Vincent J., “Atmospheric Attenuation of Microwave Power,”

Journal of microwave Power, 5(4), 1970.

Thank you