Post on 06-May-2015
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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