------------ PAGE 1 ------------ Wireless Charging of Mobile Phones Using Microwaves BY, AYSWARYA. P. R S7 , EC 13103437 sist 1 ------------ PAGE 2 ------------ THANKS TO… SEMINAR COORDINATOR: DEEPA. V. T MINOSHIMA. M ASST. PROFESSOR ASST. PROFESSOR EC DEPT. EC DEPT. SEMINAR GUIDE: ANUPAMA. A. S ASST. PROFESSOR EC DEPT. 2 ------------ PAGE 3 ------------ CONTENTS • INTRODUCTION • WHAT’S HAPPENING • MICROWAVE REGION • FREQUENCY SELECTION • BLOCK DIAGRAM • TRANSMITTER SECTION • RECEIVER SECTION • ADVANTAGES • DISADVANTAGES • APPLICATION • CONCLUSION 3 ------------ PAGE 4 ------------ 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 4 ------------ PAGE 5 ------------ CONTD… „« More you talk more the mobile get charged! „« No separate mobile charger „« Removal of talk time and battery stand by from mobile specifications „« Additives to mobile handsets: „Ï Sensor „Ï Rectenna 5 ------------ PAGE 6 ------------ WHAT’S HAPPENING? ƒæ Microwave signal is transmitted from transmitter along with message signal using slotted waveguide antenna at frequency 2.45 GHz ƒæ Charging made universal 6 ------------ PAGE 7 ------------ 7 ------------ PAGE 8 ------------ MICROWAVE REGION ƒæ Wavelength : 1 mm- 30 cm ƒæ Microwave can be used for: 1. Measuring body temperature 2. Transmitting information 3. Remote sensing 4. RADAR 5. Communication 8 ------------ PAGE 9 ------------ Microwave region of electromagnetic spectrum ƒæ We choose s – band of microwave region( 2- 4GHz) Designation Frequency range L Band 1 to 2 GHz S Band 2 to 4 GHz C Band 4 to 8 GHz X Band 8 to 12 GHz Ku Band 12 to 18 GHz K Band 18 to 26 GHz Ka Band 26 to 40 GHz Q Band 30 to 50 GHz U Band 40 to 60 GHz 9 ------------ PAGE 10 ------------ FREQUENCY SELECTION „X Select license free 2.45 GHz Industrial, Scientific and Medical ( ISM) radio bands „X ISM bands are reserved internationally for non- commercial use of RF electromagnetic fields for industrial, scientific and medical purpose 10 ------------ PAGE 11 ------------ BLOCK DIAGRAM 11 ------------ PAGE 12 ------------ TRANSMITTER SECTION Consists of two parts ƒæ Magnetron ƒæ Slotted waveguide antenna 12 ------------ PAGE 13 ------------ MAGNETRON • Magnetron is a vacuum tube oscillator that generates high- power electromagnetic signals in the microwave frequency range. 13 ------------ PAGE 14 ------------ Contd … • It is a microwave tube in which electrons generated from a heated cathode are affected by magnetic and electric fields to produce microwave radiation • Magnetron is used to produce high- power output required in radar and communication equipment 14 ------------ PAGE 15 ------------ SLOTTED WAVEGUIDE ANTENNA ƒæ It is an Omni- directional antenna 15 ------------ PAGE 16 ------------ Contd … ƒæ Slotted antenna arrays used with waveguides are popular antenna in navigation, radar and other high- frequency systems ƒæ Has high efficiency and gain of 13dB ƒæ Here we use frequency of 2.45GHz 16 ------------ PAGE 17 ------------ RECEIVER SECTION „X Basic additions to mobile phone a. Sensor b. Rectenna 17 ------------ PAGE 18 ------------ SENSOR CIRCUITRY „X Simple circuit which detects whether the user is making a call „X Simple F to V converter, this would serve our purpose „X Operating frequency of mobile phone operators for GSM system for mobile communication in India is 900MHz or 1800MHz „X Simple yet powerful F to V converter is LM2907 18 ------------ PAGE 19 ------------ CONTD… „X On the reception of the microwave signal , the sensor circuitry directs rectenna circuit to ON „X Rectenna circuit converts microwave energy to dc output „X Mobile phone begins to charge using the microwave power as long as the user talks over cell phone. 19 ------------ PAGE 20 ------------ RECTENNA „« What is Rectenna ? „« Rectenna = Rectifier Antenna. 20 ------------ PAGE 21 ------------ Contd … „« Rectenna is a rectifying circuit that converts microwave energy into DC output. „« Single Rectenna is approx 23 mm 2 , arranged to form an array suitable to the shape of mobile phone . „« Very thin as sheets and can be used at the back of the Cell phones „« In our design it consists of a single diode power rectifier in ¯ hybrid technology. with improved sensitivity at low power levels. 21 ------------ PAGE 22 ------------ RECTIFYING CIRCUIT „X The Schottky diode microwave rectifying circuit is used here as its efficiency is found to be greater than 90%. „X To make low cost power rectifier for low and high power levels of 2.45GHz with good efficiency of rectifying operation „X Used to improve transmission efficiency 22 ------------ PAGE 23 ------------ ADVANTAGES „Ï Charging mobiles wirelessly „Ï Saving time for charging „Ï Wastage of power is less „Ï Better than witricity „Ï Get charged as we make call during long journey 23 ------------ PAGE 24 ------------ DISADVANTAGES • Radiation problems may occur • Network traffic may cause problems in charging • Charging depends on network coverage • Rate of charging may be of minute range 24 ------------ PAGE 25 ------------ APPLICATIONS As the topic’s name itself it is used for “ WIRELESS CHARGING OF MOBILE PHONES” 25 ------------ PAGE 26 ------------ FUTURESCOPE and CONCLUSION • Thus this paper successfully demonstrates a novel method of using the power of microwave to charge mobile phones without use of wired chargers. • It provides great advantage to mobile phone users to carry their phones anywhere even if the place is devoid of facilities for charging. • Has effect on human beings similar to that from cell phones at present. 26 ------------ PAGE 27 ------------ Contd … • Use of rectenna and sensor in mobile phone could provide new dimension in the revolution of MOBILE POWER 27 ------------ PAGE 28 ------------ REFERENCES • Theodore. S. Rappaport , ¯ Wireless Communications Principles and Practice. • www. seminarprojects. com • www. seminarsonly. com • www. wikipedia. org 28 ------------ PAGE 29 ------------ 29 ------------ PAGE 30 ------------ Any questions ???? 30