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1. ECE 291 Senior DesignElectric Boat Team
2. Introduction This is a research project in collaboration with Electric Boat
3. Team Members Amy Henne
Jason Holland
Ricardo Silva
Mark Wojenski
4. Objective Wireless Power Transmission
Wireless Data Transfer System
5. Wireless Power Transmission (WPT) Researched Several Methods of WPT
Optical Box
RF Box
Waveguide
6. Optical Box Light source
Solar cells on individual sensor modules
Highly polished internal surfaces of box
7. Optical Box: Problems Solar cell efficiency = 18%
Light source efficiency = 65% (fluorescent)
Combined total efficiency = 11.7%
4 receivers * 2 Watts / 11.7% = 68.37Watts
8. RF Injection into Square Box RF injected into the middle of the box
Each sensor module would convert RF to DC.
9. RF Box: Problems Reflected energy
Uncontrollable dispersion of RF energy
VSWR might damage transmitter
10. Waveguide Control of propagating modes
TE10 mode dominant
Easy to calculate where power concentrations are greatest
11. Waveguide: Final Choice for WPT Waveguide System
RF Generator
WG Dimensions
RF to DC Conversion
12. RF Generator Supplies the energy used for our WPT
Operating frequency of the RF generator < frequency of data transmission
Chose Operating Frequency of 1000 MHz
13. RF Generator Voltage Controlled Oscillator (VCO) is a ZOS-1025
puts out up to 8.0 dBm (6.3mW)
RF amplifier is a LZY-2 (40 dB gain)
rated to 20 watts
14. Waveguide Dimensions Based on Frequency of Transmission
Waveguide with parameter a slightly greater than 5.9 inches and parameter b equal to 0.5*a= 2.95 inches can properly transmit our RF data
A waveguide of 7.87” x 3.93” x 5’was built by Electric Boat out of aluminum for our prototype
15. Waveguide Features Use of ARC-UD-11091 RAM material to reduce standing waves within waveguide
Separate data reception circuitry compartment
16. RF to DC Conversion - I A Rectenna, or rectifying antenna is a receiving antenna combined with a rectifying circuit, which converts RF into the desired DC power
Must be efficient in the RF to DC Conversion
17. RF to DC Conversion - II Low pass filter consists of one 10pF capacitor to filter out the ripple
1N5711 Schottky diode
High power (250 mW)
Reverse voltage breakdown at about 70V
18. Wireless Data Transmission Wirelessly transfers audio data
Data must be modulated and transmitted back to the receiver
Explored Several Different Transmission Frequencies
440 MHz Transmission
900 MHz Transmission
2.45 GHz Transmission
19. 440 MHz Data Transmission First idea was to use circuitry from inside of a toy walkie-talkie to transmit our audio data
This was dropped because the operating frequency was around 440 MHz and this did not fit with our design requirement of the WPT Transmission Frequency < Data Transmission Frequency
20. 900 MHz Data Transmission Many commercially available devices in this frequency range
Discarded because RF operating frequency of 1000 MHz is very close to 900 MHz
May cause interference between the power and data transmission
21. 2.45 GHz Data Transmission Commercially available devices including:
Home telephones
Wireless audio/video transmitters
Wireless home PC networking devices
Approximately 1.5 GHz higher that WPT
Allows better separation of signals
22. Modulation Schemes for Data Originally decided to design our own modulation circuitry
Modulation Schemes considered:
AM and FM
Spread Spectrum
Bluetooth Standard
23. Frequency and Amplitude Modulation FM and AM are modulation techniques used in commercial radio
Simple to implement
Lacks any built in resistance to electrical interference
Does not ensure there is no interference between Data and Power Signals
Shortage of available frequencies if expanded for many sensors
24. Spread Spectrum Transmitted information is spread out over a range of frequencies
improves both transmitter and receiver’s immunity to interference
Information is divided into small pieces and each piece is transmitted at a different frequency in the predetermined range around 2.45 GHz
Only a spread spectrum receiver that is tuned to sync with the transmitter will be able to receive and decode the transmitted information
25. Bluetooth Standard Characteristics of Bluetooth compatible devices include:
operation in the 2.45 GHz range
frequency hopping spread spectrum transmission
low power consumption
26. Bluetooth Standard Factors in not Choosing Bluetooth
Three development kits priced at $2500 a piece would be needed to implement our project
Scheduled to go on the Market in Summer 2002
27. 2.4 GHz Cordless Phones Commercially available
Inexpensive
Didn’t need to design our own modulation and data transmission circuitry
Experimented with two phones:
Siemens Gigaset 4015
Motorola MA350
28. Siemens vs. Motorola Originally thought Siemens would be the optimal choice because it consumed less power during operation
Average Power Consumption of 180 mW
Current spike of up to 600 mA at turn on
Motorola was ultimately chosen
Average Power Consumption of 265 mW
No current spike at turn on
29. Final Design Waveguide for WPT
RF Generator
RF to DC Conversion
2.4 GHz Motorola Phones for Wireless Data Transmission
Allows multiple signals to be sent simultaneously
30. Final Design Antenna from the handset of the phone is positioned so that it enters the waveguide
Phone’s antenna will transmit to the base stations that are placed in the second compartment of the waveguide
31. RF Distribution and Data Transmission
32. Voltage Regulator Circuitry for Phone Box
33. Circuitry for Phone Box
34. Adjustable 1-14VDC Power Supply with Vtrip for VCO Power
35. Adjustable 1-16VDC Power Supply with Vtrip for VCO Frequency
36. UCONN Budget and Expenses WPT
$610.00
Data Transmission
$400.00
Miscellaneous
$400.00
Current Budget $1410.00
Other parts supplied by EB
37. Project Phases and Timeline
38. References 1. Microelectronic / Optoelectronic Devices, Supplementary Notes, Part 1, F.C. Jain, UCONN, Spring 2002.
2. http://acre.murdoch.edu.au/refiles/pv/text.html, website with information on solar cells.
3.http://www.kurasc.kyoto-u.ac.jp/plasma-group/sps/milax-e.html , website with information on RF to DC conversions.
4.http://www.fnrf.science.cmu.ac.th/theory/waveguide/Waveguide%20theory%206.html , website with information on waveguides
5. http://www.cwc.nus.edu/~sg/~cwcpub/zfiles/ap98.pdf , website with information on rectennas.
39. Acknowledgements Professor Rajeev Bansal, University of Connecticut
Mr. Michael Sullivan, Electric Boat
Angel Rodriguez
40. Questions?