This document proposes a method for wirelessly charging mobile phones using microwaves. It describes the system in terms of a transmitter section that uses a magnetron to generate microwaves, and a slotted waveguide antenna to transmit them. At the receiver, a rectenna converts the microwaves to DC power to charge the phone battery, while a sensor detects when a call is being made to activate the charging. Advantages include eliminating wired chargers and using a single transmitter for multiple providers, while disadvantages include potential health effects and high costs.

1. Wireless Charging of Mobile
Phones Using Microwaves
By,
HARISH N NAYAK
8th SEM ECE

2. CONTENTS
• INTRODUCTION
• MICROWAVE REGION
• BLOCK DIAGRAM
• TRANSMITTER SECTION
• RECEIVER SECTION
• ADVANTAGES
• DISADVANTAGES
• APPLICATION
• CONCLUSION

3. INTRODUCTION
 Mobile phones becoming basic part of life
 Recharging of mobile phones is a big problem
 Objective—to recharge any mobile phone independent of manufacturer
and battery make
 Achieved by recharging battery while talking using microwaves
Additives to mobile handsets:
Sensor
Rectenna

4. MICROWAVE REGION
 Microwaves are the Radio wave which has the wave length range of 1 mm to 1 meter
and the frequency is 300MHz to 300GHz.
 Microwaves are good for transmitting information from one place to another
 It is because microwave energy can penetrate rain and snow, clouds, and smoke
 The frequency selection is another important aspect in transmission. Here we are going
to use the S band of the Microwave Spectrum, which lies between 2-4GHz.We have
selected the license free 2.45 GHz band for our purpose.

5. PRINCIPLE OF OPERATION
Slotted waveguide
Antenna
mobile signal
circulator
sensor
Transmitting station with the
microwave transmitter
RF cable
Rectenna
waveguide

6. OPERATION
 Here as we can see there are two part. One is transmitting part and the other is the
Receiving part
 At the transmitting end there is one microwave power source which is actually
producing microwaves
The microwave signal is transmitted along with message signal using slotted wave
guide antenna
At the receiver side 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.

7. TRANSMITTER SECTION
The transmitter section consists of two parts. They are:
 Magnetron
 Slotted waveguide antenna
Magnetron

8. MAGNETRON
Magnetron is a high power microwave oscillator and it is used in
microwave oven and radar transmitter.
Magnetron is the combination of a simple diode vacuum tube with built in
cavity resonators and an extremely powerful permanent magnet.
Magnetron is capable to deliver more power than reflex klystron or gunn
diode
Magnet is setup to affect the path of travel of electrons that are in transit
from cathode to the anode plate.

9. THE SLOTTED WAVEGUIDE ANTENNA
The slotted waveguide antenna consists of 8 waveguide sections with 8 slots on
each section. These 64 slots radiate the power uniformly through free space to the
rectenna. The slotted waveguide antenna is ideal for power transmission because
of its high efficiency (> 95%) and high power handling capability.
Slotted antenna arrays used with waveguides are popular antenna in navigation,
radar and other high-frequency systems
Has high efficiency and gain of 13dB
Here we use frequency of 2.45GHz

10. RECEIVER SECTION
RECTENNA
The basic addition to the mobile phone is going to be the rectennas and sensor
Rectenna = Rectifier + Antenna.
A rectifying antenna called a rectenna receives the transmitted power and converts the
microwave power to direct current (DC) power.
Here antenna receives the microwave signal and diode rectifies the current induced in
the antenna by the microwave
This demonstration rectenna consists of 6 rows of dipoles antennas where 8 dipoles
belong to each row. Each row is connected to a rectifying circuit which consists of low
pass filters and a rectifier.
The rectifier is a GaAs Schottky barrier diode that is impedance matched to the dipoles
by a low pass filter.

11. SENSOR CIRCUITRY
The sensor circuitry is a simple circuit, which detects if the mobile phone
receives any message signal. This is required, as the phone has to be
charged as long as the user is talking. Thus a simple F to V converter would
serve our purpose.
 In India the operating frequency of the mobile phone operators is generally
900MHz or 1800MHz for the GSM system for mobile communication.
Thus the usage of simple F to V converters would act as switches to trigger
the rectenna circuit to on.
 A simple yet powerful F to V converter is LM2907.

12. ADVANTAGES
The use of wired chargers are eliminated.
The need of different types of chargers by different manufacturers is totally
eliminated
The phone can be charged at any place and any time.
Only one microwave transmitter can serve to all the service providers in that
area.
The more we talk the more the phone get charged

13. DISADVANTAGES
Wireless transmission of the energy causes some effects to human body, because
of its radiation
Network traffic may cause problems in charging
Practical possibilities are not yet applicable as there is no much advancement in
this field.
Process is of high cost
Charging depends on network coverage

14. CONCLUSION
This paper successfully demonstrates a novel method of using the power
of the microwave to charge the mobile phones without the use of wired
chargers. Thus this method provides great advantage to the mobile phone
users to carry their phones anywhere even if the place is devoid of
facilities for charging.
A novel use of the rectenna and a sensor in a mobile phone could provide
a new dimension in the revelation of mobile phone.