ACKNOWLEDGEMENT

The Tryst 2010 Team expresses a special acknowledgement to the following people for doing a dedicated job of reviewing and selecting the papers:

Ritu Garg (Computer Science),Smruti Padhy (Computer Science), Ehtesham Hassan (Computer Science), Hitesh Shrimali(Electrical), Priyesh Chauhan(Electrical), M Sultan Siddiqui(Electrical), Anoop C Nair(Electrical), Gaurang Vakil (Electrical), Vimal Singh (Electrical), Shankar (Electrical), Kiran (Mechanical), Hariharan (Mechanical), Anand Dhruv (Mechanical), Dr. Anima Nagar(Mathematics), Dhirendra Singh (Mathematics) , Dinbandhu Pradhan (Mathematics), Sarvesh (Mathematics), Dr. Anurag Rathore(Biochemical), Dharmendra Kumar Gupta(Chemistry), Rajesh Chhatra (Chemistry), Nem Singh(Chemistry), R.P. Verma (Chemistry), Bharat Gadakh (Chemistry), Archana Jain (Chemistry), Dr. Joby Joseph(Physics), Gautam Singh (Physics), Bhupendra Kumar Sharma (Physics), Charu Chandra Korde (Civil), Vivek Kumar (Instrument Design & Development Centre), Rajendra Singh Malik (Centre Of Polymer), Immanual (Chemical Engineering) , Jabez (Chemical Engineering)

INDEX

Computer Science

1. WiMAX‐A wireless technology for “Y”oung generation

Praneeth Kumar P, Rajashekar B, Mohan Rao R, Sony Winner, Sujith Simon Reddy G 1

2. Adaptive Steganography: Design of a robust algorithm for cover image ranking and use of

hashing as an authentication mechanism

Sugandha, U. Satya Naga Vineeli 10

3. ANN based character recognizer for mobile devices to help visually challenged

M.Karthikeyan,K.K.Prasanna kumar 15

4. Unsupervised Detection of Unusual Activities

Saurabh Gupta, Ankit Sagwal, Ayesha Choudhary, Subhashis Banerjee , Ankit Narang 21

5. Establishment of Portable Bidirectional Communication for Aiding Rescue Operations after

Disaster

Akhilesh R. Jaiswal, Bharat J. Shinde 27

6. Facial Analysis Between Age Groups Using Distance Matrices

Q. M. Rizvi , R. Asthana 34

7. Gait As A Biometric For Human Recognition

Lekha M.K. Kankane, Yogita A.K. Malpani 38

8. Hiding Sensitive Rule Using Distortion Technique

Lekha M.K. Kankane, Yogita A.K. Malpani 45

9. Image Augmented Inertial Navigation System

M. Sharma, K. Paul, S. Gupta, A. Kansal, S. Dhakar, P. Jain 51

10. iMOUSE – A virtual mouse using face recognition

G.Vaidyanathan, K.Mohan Kumar 55

11. Intelligent transportation system using genetic algorithm for shortest driving time calculation

S.Lokesh raj ,V.Aranganathan ,M.A.karthik kumar 62

12. Internet in Space

Vinay D.Khandagale, Nilesh B. Bhagat 66

13. Neural Networks And Fuzzy Logic In Unmanned Aircraft

S. Thirumurgan, V. S. Venkatraman, M. Praveen 73

14. Steganography

K.Mohan Krishna, K.Agastya Kumar, G.Ganesh Kumar 82

15. The Friend Locator

Harsh Kumar, Harsh Sama, Richa Dhanuka 89

Electrical

16. 3D‐ Face Recognition Using Biometrics

Praneeth Kumar P, Rajashekar B, Mohan Rao R, Sony Winner, Sujith Simon Reddy G 92

17. 4G Technology

Abrar Ahmed T.S., Azarudin. M 105

18. Digital to Digital Converter Using Delta Sigma Modulation

Ketan Bansal, Rhishabh Garg, Shouribrata Chatterjee 114

19. A solution to reduce commercial losses in PowerSystem

B. Karthik, Karthik.Bhattu, 117

20. Density based Energy LEACH Protocol for Wireless Sensor Networks

M. Khulbe, P. Srivastava, R.C. Jain 124

21. Electricity generation: Extraction with conservation

Pawan Kumar 128

22. Euclid Greatest Common Divisor

Shikhar Agarwal , Sandeep Kumar Bindal 131

23. A Proactively Secure Threshold Multisignature Scheme

Subanya.B, Abinesh.K.T, Kavitha Mani.R 134

24. On SHA Family of Algorithms

Srijan Sanket, Anshul Jain 142

25. Optical Layer Technology In Telecommunication Network

Miss Suryateja Nagula 145

26. Optimization of Power Subsystem in a Picosatellite by Battery Module Restructuring

Ganesan Varun Aiyar 151

27. Privacy Threats in E‐passports Using RFID & Biometrics

Sai Prasanth D.V.,Karthick S., Rajarajan R. 157

28. Security Providence for Luggages Using Bluetooth

S.Karthikeyan, S.Kishore, L.Srinivasan 165

29. Usage of PICs’ in EMP bomb resistant circuits

A.V.R.Sharath Chandra, M.Sesha Sai 169

30. Utilization of phase changing materials for thermal management of mobile electronic devices

Sonal Thengane, Nikhil Bhargava 176

31. Wireless Power Transfer using Small Loop Antennas

Karan Goel, Parikshit Vasisht 181

Robotics

32. Anti Hiv Using Nano Robots

Jeevankumar Reddy.Patil, Manikanta.Gummadidala 184

33. Optimizing storage conditions for fruit ripening process

Pallavi Swaroop, Neha Jain 193

34. Remotely Controlled Combatant Robots in Defence Guided by Telepresence and Immersive VR

Systems

V.Guru viswanath ;K.Vikas;A.Vibinth 197

35. Voice Recognized Automated Pen

Gaurav Rajput, Anway Mukherjee 204

Wireless Power Transfer using Small Loop Antennas 181

Tryst Technical Conference, IIT Delhi 13-14 March, 2010

Wireless Power Transfer using Small Loop Antennas Karan Goel

#, Parikshit Vasisht

*

#Department of Electronics and Communication Engineering, Apeejay College Of Engineering, Sohna *Department of Electronics and Communication Engineering, Apeejay College Of Engineering, Sohna

#Email:karan.goel09@gmail.com

#9911163191 *Email:parikshitvasisht@yahoo.com

*9899315555

Abstract— We propose an effective design to transfer electricity

up to a non-negligible distance without any connecting wires

using small loop Antennas. For demonstration we have designed

a theoretical model for a prototype to transmit electric power up

to 100W wirelessly over mid-range distance (5m) and light a 60W

bulb. We also give an overview of the techniques used to design

the prototype and compare the simulation and the actual

practical results of the electronics hardware used.

Keywords— Witricity, wireless power transfer, Orcad Pspice

analysis

I. INTRODUCTION

A. Motivation

For the past decade or so there has been a tremendous

growth of autonomous electronic devices (such as I-pods,

mobile phones, laptops, PDA etc) which rely primarily on

stored chemical energy for their power needs. If a technology

can be developed to transmit power wirelessly, it will get rid

of wire mesh and clutter and portable devices could get

charged wirelessly.

Wireless power transfer can also be used to power nano-

devices like MEMS and bio-tech devices like pacemakers, which would prevent the repetitive surgeries a patient needs to

undergo for charging his pacemaker.

The project required an extensive practical and theoretical

knowledge of both Engineering electromagnetic theory and

analog electronics and thus provided us with a challenging

opportunity to understand these core concepts of Electrical

engineering at a much deeper level.

B. Theory

The fundamental physics behind wireless energy transfer is magnetic resonance. This resonance is similar to the

mechanical resonance which can be easily observed in the

shattering of glass experiment. When two coils are in

magnetic resonance, they tend to exchange energy between

themselves while interacting negligibly with Extraneous

objects. Note that the technique is different from simple

inductive coupling in which the coils need not be in resonance

to exchange energy.

C. Our Approach Vs Existing Approach

Serious research has been going on for the past few years to

develop efficient techniques for transferring power wirelessly,

most notably by the team of Kralis of MIT and their company

called Witricity (which is a portmanteau for wireless

electricity)[1].However there are a few notable differences

between our approach and the one used by the MIT team. We have designed the antenna as a single turn coil which

reduces the complexity and cost of antennas. Also the whole

prototype including the electronics cointaing the RF Amplifier

has been built indigenously using locally available parts to

ensure minimum costs. Our experimental setup can be

represented by the following diagram.

Fig. 1 The Prototype setup

Wireless Power Transfer using Small Loop Antennas 182

Tryst Technical Conference, IIT Delhi 13-14 March, 2010

II. POWER SUPPLY DESIGN

The Power Supply is used to generate a High Frequency

sinusoidal current which generates a HF alternating magnetic

field when connected to the resonant coil (Transmitter). The schematic Diagram below shows Oscillator and the Voltage

Amplifier stage of the power supply

Fig. 5 Actual Digital Oscilloscope Output

Fig. 2 10MHz Colpitts Oscillator and Voltage Amplifier Schematic

The general purpose amplifier transistor Q2N3904 is used for designing the Oscillator and High voltage transistor

MPSA44 is used in the first stage of the transistor. The first

stage of voltage amplifier is designed with an input impedance

of 50Ω and a voltage gain of about 55dB.

A. Oscillator Design

We decided to use the Colpitts Oscillator to generate the 10

MHz sinusoidal wave due to its low part count and inherent

simplicity and stability. The circuit has been designed using

Cadence Orcad Package and simulated using Pspice. The

Oscillator circuit is shown in figure 2. The simulated output of

oscillator has a peak voltage of ≈ 500mV [figure 4].

Fig. 4 Simulated Oscillator output in Pspice

The Actual Digital Oscilloscope output of the breadboard

prototype is ≈328mV [figure 5].

Thus we have acceptable performance and acceptable match

between theoretical and practical results for the oscillator.

Note that the noise on the waveform presents no disadvantage

as we simply want to create a high frequency alternating

magnetic field to transfer power and are not doing a

communication protocol. (E.g. Modulation).

B. Voltage Amplifier Design

The ac π-model was used to analyse and design the voltage

amplifier [figure 6].

Fig. 6 Equivalent π-model of voltage Amplifier

The MPSA44 High Voltage transistor is biased with a collector current of IC=100mA. The circuit schematic is

shown in figure 2.

The Output Power of the voltage amplifier is 1W which is

given to a Class AB Push Pull Power Amplifier with a Power gain of about 100.This gives an output power of 100W which

is connected to the resonant coils.

Wireless Power Transfer using Small Loop Antennas 183

Tryst Technical Conference, IIT Delhi 13-14 March, 2010

III. ANTENNA DESIGN

Two single loop antennas [figure 6] have been designed

which have an impedance of about 8Ω. These antennas are

connected to two bank capacitors whose capacitance can be

varied to tune the resonant frequencies for both single loop

Antennas. The tuning of the two antennas is critical; otherwise

power will not be transferred at maximum efficiency.

Fig. 6 Actual Photo of the Single Loop Antenna

The maximum spacing between the resonant coils (transmitter and receiver) is calculated using the following derived

equation.

This equation is derived by equating the near field and the far

field due to the loop antennas. R is the distance between the

two coils (Transmitter and Receiver) and λ is the wavelength

of the field. For a frequency of 10 MHz, the maximum

theoretical separation possible between the two resonant coils

is 5m.

IV. CONCLUSIONS

In conclusion, we investigate the feasibility of wireless power transfer and present a theoretical model for a prototype

which is built from ground up by implementing the basic

concepts of Electronics and Electromagnetics. Note that the

technology is completely safe for Human beings as living

beings are negligibly affected by the resonant magnetic field

generated in our experiment which is of the same order as that

of the Earth’s magnetic field.

We also conclude that the current technique can be refined and further research can be done to boost efficiency and/or

range and pave the way for commercial exploitation of the

technology.

The current supplied by the power supply is given by

where I is the alternating current. This current generates a

magnetic field, which is coupled between the two resonant coils and alternating current is generated in the receiver coil.

Thus power is thus transferred to the receiving antenna which

is connected to a resistive load.

REFERENCES

[1] A. Kurs, A. Karalis, R. Moffatt, J.D. Joannopoulos, P. Fisher, M. Soljačić, “Wireless Power Transfer via Strongly Coupled Magnetic Resonances,”

Science, Vol. 317, 6 July 2007.

[2] A.Malvino and David J Bates, Electronic Principles 7th Edition, Tata McGraw Hill Special Indian Edition 2007.

[3] W.H Hyat and J.A Buck, Engineering Electromagnetics 7th Edition, Tata McGraw-Hill Special Indian Edition 2007.

.