STUDENT PROJECT PROPOSAL By

DEEPAN.K

PRABHAT KUMAR

NISHANT KAILASH

UNDER THE GUIDANCE

Of

Dr.K.Suresh manic

Professor and Head

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

SRIRAM ENGINEERING COLLEGE PERUMALPATTU TALUK

THIRUVALLUR DISTRICT-602024, PH: 04427689364

IEEE MADRAS SECTION

ISTE PROFESSIONAL CENTRE

CHENNAI-600025

A PROJECT REPORT ON

WIRELESS RF-POWER HARVESTING (HARVESTING POWER FROM AIR)

PROPOSED BY : DEEPAN.K (4th-yr)

PRABHAT KUMAR (4th-yr)

NISHANT KAILASH (4th-yr)

EMAIL ID : deepan.ss22@gmail.com

CONTACT NO : 9840838873 ,9551030932

FORMAT FOR STUDENT PROJECT PROPOSAL 2010-2011 1. Name of the applicant(s) : DEEPAN.K PRABHAT KUMAR NISHANT KAILASH

2. a.Address including email : SRIRAM ENGINEERING COLLEGE, PERUMALPATTU and mobile number (Institutional) Thiruvallur-602024 deepan.ss22@gmail.com Mob : 9951030932, prabhatroket@gmail.com , Mob : 9840838873 hotgodgnishu03@yahoo.com Mob:9444965244 b.IEEE Membership details : DEEPAN.K (90927826) PRABHAT KUMAR (90927731) NISHANT KAILASH (90928525) 3. (a)Your present academic programme :B.E./EEE (b) The discipline in which your proposal is to be considered : Engineering& Technology

4. Percentage of Marks Scored up : Deepan.K (80%)

Previous semesters Prabhat Kumar (76%)

Nishant Kailash (75%)

5. Are you an aspirant for research : YES career? If so, a) Are you planning to sit for : GATE UGC/CSIR-NET/GATE Please provide full particulars b) Are you ambitious of publishing : YES in a science journal? If so are you willing to continue with your supervisor until the manuscript of the paper is communicated. 6. Whether your Department/College/ : AICTE University is recognized by the UGC/NAAC/ICAR/AICTE/ICMR

7. a) Name of the guide : Dr K.SURESH MANIC with Designation Professor & Head /EEE

Mobile no : 9940423351 b) Institutional address : SRIRAM ENGINEERING COLLEGE PERUMALPATTU, TIRUVALLUR DIST. PIN CODE-602024 Ph: 044-27689364 8. Title of the proposed work :WIRELESS RF-POWER HARVESTING (An innovative approach of harvesting power

from RF(air) for charging applications ) 9. Attach 1 Copy of work containing : Enclosed

1. Introduction 2. Objectives 3. Methodology 4. Work Plan 5. Budget 6. Other details

10. Any other particular that you wish : This project was shortlisted in NATIONAL to include. LEVEL STUDENT’s INNOVATION Competition, held in ANNA UNIVERSITY TECHKNOW 2K10

INTRODUCTION:

In recent days charging our mobile phones is a time consuming work for everyone. We are presenting here a wireless charging of mobile phones by RF-POWER HARVESTING TECHNOLOGY.

A station having a means for receipt for ambient energy from the environment and energizing power storage devices of objects of interest comprising one or more antennae and circuitry for converting said ambient energy into DC power for energizing said power storage devices. The antenna of the station is tuned to maximize DC energy at the output of the rectifier/charge pump. The station can be used to energize power storage devices including capacitors and batteries that are used in electronic devices, such as cell phones, cameras, PDAs.

BACKGROUND OF THIS TECHNOLOGY:

In the operation of this technology, ambient RF and generated RF signals provide a source of Potential Energy that can be gathered, stored and supplied to a multitude of devices requiring electrical energy.

Traditional RF receiving devices utilize an antenna to capture a narrow band of frequencies within the RF spectrum, whereby the collection of RF frequencies is then filtered are tuned, to a specific frequencies for the purpose of maximizing signal being transmitted within the chosen frequency. The Potential Energy contained in the signal is then used for its intended purposes, such as audio, video, or data processing. These RF receiving devices have focused on maximizing selectivity of the frequency in order to isolate and to be coherent without interference from other sources.

OBJECTIVE:

According to this RF-POWER HARVESTING technology, we can convert DC into RF radiation using diode coupled with monolithic resonator circuit. Usually Radio frequency is linked with mobile and radio communication and it is present throughout the atmosphere. We can convert the RF radiation present in the atmosphere into DC voltage which can be used to power small scale applications such as Mobile phones, iPods, Trimmers, Bio-medical instruments etc…

In receiver side we have an apparatus for a wireless power supply including a mechanism for receiving a range of radio frequency radiation across a collection of frequencies. This apparatus includes a mechanism for converting the radio frequency radiation across at a same time into DC. A method for wireless power supply including the steps of receiving a range of radio frequencies across a collection of frequencies. There is the step of converting the radio frequency radiation across the collection of frequencies same time into DC.

METHODOLOGY:

BLOBK DIAGRAM:

The atmospheric air is used as a RF source. By the use of receiver circuit, we are extracting the power from the atmosphere. The block diagram of the receiver circuit is shown below.

Receiver Block Diagram

CIRCUIT DIAGRAM-1 :-

Fig.1

CIRCUIT DIAGRAM-2:

CIRCUIT DIAGRAM-3:

EXPLANATION:

The present technology pertains to an apparatus for a wireless power supply. The apparatus comprises means for converting the RF radiation across the collection of frequencies, preferably at a same time in to dc.

RF signals striking an antenna are fed in to an inductor (L), which is resonant for the desired band at RF spectrum. (NOTE: In areas with a high concentration of RF energy, there is no need to attach an antenna.)

The absorbed RF energy, consisting of fundamental harmonic, inter-harmonic and standing waves is accessed via taps 20(T1-Tx) on the inductor (18), which are placed at points along the inductor. A key characteristic of this device is that a capacitor-less front- end allows for the inductors wide bandwidth and maximum admittance of the incoming RF energy. The tap points are calculated by matching the inductor sections impedance to the desired RF range.

The result and RF energy, available at each tap point is rectified by a device, such as diodes 26(D1-Dx) and converted in to dc voltages. The individual rectified voltages are spread among a series capacitor integrator consisting of capacitors (C1-Cx). This broad band approaches allows maximum energy to be spread among the series capacitors stack.

The sum of the voltages available from C1-Cx is stored in any storage devices such as capacitor or a group of capacitors Cs(S1-Sx) and made available for immediate use, or to sup[ply electronic devices requiring intermittent power. The electrical characteristics of the storage devices as capacitors, the configuration and actual number of storage device is dependent on the voltage and power requirements of the devices .The apparatus 10 is delivering power to(see figure).

Although not considered part at the apparatus 10, the antenna 22 is an integral component of any practical device utilizing the method and apparatus 10 described. The key characteristics of the antenna would be that, it is capable of wide band reception, optimized for the chosen bandwidth, and takes in to consideration the necessary effective area to support the power requirements of the target device.

Ideally, the antenna impedance is matched with the inductor impedance of the apparatus.

DESCRIPTION:

Recharging devices using an RF electromagnetic field radiation into free space have been described in this paper for wireless powering and recharging a battery charging arrangement in which a rechargeable charge storage device is placed in an RF or microwave radiation field .In one aspect of the invention, a charged storage device is charged exposing the charge storage

device to an RF electromagnetic field radiation into free space. The charge storage device includes one or more antenna dispose on the device and adapted to receive the radiation RF electromagnetic field. One or more rectifier are connected to the antenna for rectifying the received RF electromagnetic field into a dc output current .The dc output current produced by the rectifier is used to charge the charge storage device.

The antenna may be one or more dipole antenna which may be combined to form at least two subsets of dipole antenna element arrays, where in one subset may be oriented at an acute or a right angle with respect to at least one other subset. The antenna or dipole antenna may be placed on more than one outside surface of the charge storage device which enclose an acute or a right angle with each other .To efficiently couple the antenna array to the radiation field, each of the antenna element of the array preferable has a length of approximately (wavelength/2) of rf radiation .If more than one dipole is used ,the space between adjacent antenna dipoles is preferably wave length/2.The number of dipole determines the power conversion efficiency of the antenna array.

Resonant antennae such as dipole antennae are more efficient for given length of wire, but are restricted to narrow bandwidth. Most present day users of antenna for

communication. Here we are using antenna for collecting the frequencies and processing it.

a .INDUCTOR:

The characteristics of the inductors are dependent on the chosen bandwidth of frequencies to be collected and utilized. The ideal inductor should be constructed so that the mid-point of total inductance would be resonant at the centre frequency of chosen RF segment or spectrum.

Multiple taps (20) provide fundamental and inter-harmonic output voltage from the selected band segments of RF energy.

For Example: A Medium wave circuit (figure), utilizing an antenna impedance of 375 ohm, in to an inductive circuit of 375 ohm of reactance, with centre frequency of 1.2MHZ would require an inductance of 100 Micro Henry. The effective bandwidth would be approximately 2MHZ wide, (-3 db down at each end of band).

Inductance can be calculated by standard resonance formula

L= (D square times N squared)/ (18 times D plus 40 times F)

Where,

L= inductance in Micro Henry.

D= conductor diameter in inches.

J= conductor length in inches

N= number of conductors iterations

Using similar formulae, the required inductance can be re-calculated for Henry, milli Henry, Pico Henry and Nano Henry i.e. VLF, LF, MW, HF, UHF and microwave frequency band segments.

Utilizing a capacitor less front-end insures the inductors wide bandwidth and maximum admittance to the incoming RF energy.

b .TAPS 20:-

Taps 20are to be constructed and placed at points along the inductor 18. Each tap provides an individual output voltage into the rectifying portion of the apparatus 10.

The number of taps 20 from the inductor 18 can be calculated by the following formula.

Tn=BW times pi

Where

Tn=total number of taps.

BW=effective bandwidth of inductor (in MHz).

Pi=3.1416

The default position of each tap on the inductor 18 is equidistant along the inductor 18. Tap positions can also be calculated for optimum output voltage. When calculating the taps 20 one must take into consideration know frequencies within the chosen band segment that contain higher RF energies, and using a standard resonance formula each individual tap can be calculated for the required frequency and optimum voltage output.

c .RECTIFIER:-

The RF energy available at each tap is converted into DC voltage via a rectifying device. The type of rectifying device to be used is dependent on the chosen frequency band, and includes crystal, germanium, silicon, and other types.

d. INTEGRATOR:-

A voltage integrator is composed of capacitors (C1-Cx). The values of these capacitors are dependent on the chosen frequency band, the unique characteristics of the rectifiers and the load imposed by the storage stage. The reactance of this circuit varies greatly, even during normal operation. However, one can use a standard formula for capacitive reactance as a starting point for preliminary calculations.

XC=1/ (2*pi*F*C)

Where

Xc= capacitive reactance in ohms.

C= Capacitance in microfarads.

F=frequency in Hz.

Pi=3.1416

e .ANTENNA:

The antenna for efficiency energy harvesting may have characteristics that are different from those of a communications antenna. The antenna types and forms covered in this disclosure include:

1. A classical antenna in the sense of communications to be used as a transmitting or receiving antenna such as a monopole, a dipole, bow-tie or loop antenna.

2. An antenna array wherein each antenna in the array is substantially the same from antenna to antenna.

3. An antenna array wherein each antenna in that array is tuned to a particular frequency or range of frequencies.

The antenna of this technology is tuned to produce the maximum DC energy at the output of the rectifier/charge pump. A station includes circuitry for converting said ambient energy into DC power for energizing said power storage devices. In case of a classical antenna the circuitry may include the antenna being connected to a classical tuning element specifically designed for energy harvesting.

In case of a classical antenna array, wherein the each antenna in the array is the same from antenna to antenna, the electrical collection of antennae inputs may be connected to a classical tuning element or to a tuning element specifically designed for

energy harvesting. In this case, the DC outputs can be combined to obtain a higher voltage as the DC outputs will be connected in series. The situation here is one depicted as a relatively narrow band frequencies being harvested with the outputs connected in series. Finally, in the case of an antenna array, wherein each antenna in that array is tuned to a particular frequency in the RF spectrum, the DC outputs of each antenna can combine in series to obtain a high DC voltage.

STORAGE:-

Storage components are determined by the power requirements of the attached devices, and the available RF energy absorbed by the inductor (L).

Using a medium wave example, a 2200 microfarad electrolytic capacitor is used as storage.

Sample apparatus 10: Medium wave (AM) wireless power supply.

A device has been constructed, using the method stated above, which uses the ambient (existing) AM broadcast band of the RF spectrum as its source of energy. The devices primary purpose is to optimize the energy absorbed, collected and converted to reusable power.

The size and characteristics of the antenna required for the circuit to operate are not considered design requirements for the apparatus. The antenna needed to obtain sufficient energy to charge a storage device in a typical urban area with several AM radio stations, would be similar to one used for a standard AM radio. In areas where there is high concentration of RF energy, the apparatus itself, without an antenna 22, is sufficient to develop stored power.

The inductor 18 is in the form of an air coil comprised of enameled # 28 gauge wire wound onto a 2” form. The coil is a

continuous tightly wound wire with taps 20 placed very twenty turns with a total of six taps 20 available (T1-T6). The top of the coil in where the antenna 22 is connected. The bottom of the coil is connected to ground.

Germanium diode (IN34A) (D1-D6) are connected to each tap on the coil. The series capacitor integrator (C1-C6) is constructed as illustrated with the C6 attached to ground. C1-C6 is poly capacitors with a 0.068 microfarads rating. The power storage device 28 utilized in this sample apparatus 10, C7, is a 220 microfarads electrolytic capacitor.

Very wide band operation can be utilized by coupling multiple instances of the broadband wireless power supply together.

For Example:

A BWPS circuit designed and constructed (see design for considerations) for a Very Low Frequency wave segment (60Hz center frequency),can be coupled into another BWPS circuit designed and constructed (see design for considerations) for an Ultra High Frequency wave segment (5GHz center frequency).The outputs of each individual circuit connect (via another integrator circuit) into a common storage device (i.e., capacitor) to “pool” collected and converted RF energy together. This technique can be repeated for any or all segments of energy spectrum.

WORK PLAN:

OCTOBER: Literature survey and collection of documents.

DECEMBER: Preparing flow charts and designing of circuits.

JANUARY: Fabrication of circuits.

FEBRUARY: Implementation and obtaining the output.

BUDGET:

S.NO COMPONENTS NUMBERS PRICE(in Rs) 1. RF Transmitter 1 6500 2 Antenna 1 2000 3 Voltage Regulator 25 250 4 Capacitors ,Inductor,

Diodes. Each 100 2500

5 Voltage Amplifier 2 1000 6 Batteries 3 1500

The Budget required for this project is Rs.13750

All details will be furnished after completion of the project.

CONCLUSION:-

As we are emerging toward fourth generation of mobile communication it’s almost necessary to charge our mobile at regular times. By implementing the technology of converting available RF energy in atmosphere into and DC power many of our small electrical apparatus can be recharged wirelessly. It is the most cost effective method for recharging. And the apparatus can be recharge almost everywhere.

REFFERENCE:-

• Brown, William C.,”The Early History Of wireless Transmission”, Solar Energy, vol.56, No 1, pp.3-21(1996).

• Q.Huang and M.Oberle,”A0.5mw Passive Telemetry IC For Biomedical Applications,”IEEE Journal of Solid state Circuits,voi.33,pp 937-946,1998.

• K.Finkenzeller,RFID handbook:Fundamentals and Applications in Contactless Smart Cards and Identification,2nd Edition,Newyork:Wiley,1999.

• F.Kocer,P.M.Walsh and M.Pflynn,”An RF Powered,Wireless Temperature Sensor in Quarter Micron sCMOS,”ISCAS,2004.

• J.F.Dickson,”On Chip High Voltage Generation in MNOS Integrated Circuit using an Improved Voltage Multiplier Technique,”Journal of Solid State Circuits,vol-SC11,No.3,1976.