Project #1 Improved RF Signal Propagation through Water via Waveforms

Student: Ritesh J. Patel Electrical and Compute Engineering ACCEND Justin Jantzen Aerospace Engineering

Mentor: Dr. Dharma Agrawal, D.Sc. Distinguished ProfessorAnagha Jamthe Graduate Student Mentor

NSF Type 1 STEP GrantSponsored By

The National Science FoundationGrant ID No.: DUE-0756921

 College of Engineering and Applied Science

University of Cincinnati

Index

Experiment PurposeBackgroundMaterialsTest MethodTest ResultsConclusion

Experiment Purpose

Improvement in RF (Radio Frequency) signal propagation between a wireless transmitter/receiver pair through a pipe filled with air vs. RF signal propagation through water

A hollow pipe can be used to propagate signal through air rather than water and could significantly improve the signal quality and transmission range

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Background

RF waves are used by cell phones to communicate with a microwave tower

Such signals attenuates quickly in water due to absorption/attenuation properties

Such wireless devices communicating with RF signals could be used in off-shore oil-drilling platforms, submarines, and marine life applications

A hollow pipe can be used to propagate signal through air rather than water and could significantly improve the signal quality and transmission range

Background

3 Major Methods of Transmission Radio Frequency Acoustic Optical

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Background

From “Re-Evaluation of RF Electromagnetic Communication in Underwater Sensor Networks”

Materials

• Copper & PVC pipes of varying diameters cut into 1m segments• 1 m PVC pipe with diameter: 1.5 inch, 2 inch and 3

inch

• Trash-can filled with water

• RF Sensors operating at 2.4 GHz• Texas Instrument eZ430-RF2500-SHE

Test Method

• Transmit signal through pipe (copper & PVC) and two plastic bags in air

• Transmit signal through pipe (copper & PVC) and two plastic bags by placing pipe and plastic bags in water

• Compare the RSSI percentage of copper, PVC and two plastic bags in air

• Compare the RSSI percentage of copper, PVC and two plastic bags in water

• Use different diameter (1.5 inch, 2 inch, & 3 inch) of pipes to see diameter’s effect on RSSI percentage

Air Water

Test Method

ReceiverStation

TransmitterStation

ReceiverStation

StationTransmitter

Test Results

Stacked Histogram of RSSI Percentages of the 3 Methods When Not Submerged in Water

Test Results

3-D Histogram of RSSI Percentages of the 3 Methods When Not Submerged in Water

Test Results

Figure 3: Stacked Histogram of RSSI Percentages of the 3 Methods When Submerged in Water

Test Results

3-D Histogram of RSSI Percentages of the 3 Methods When Submerged in Water

Test Results: Summary

Average Percent Signal ReceivedPlastic Bags 1.5" Copper Pipe 1.5" PVC Pipe 2" PVC Pipe 3" PVC Pipe

Not Submerged 59.62 35.68 66.52 65.30 58.31

Not Submerged σ 0.997 2.408 1.040 2.347 2.735

Submerged 32.77 0.00 43.02 40.26 43.01

Submerged σ 1.17 0.00 0.61 2.08 2.54

Average Percent Signal LostPlastic Bags 1.5" Copper Pipe 1.5" PVC Pipe 2" PVC Pipe 3" PVC Pipe

Not Submerged 40.39 64.32 33.49 34.70 41.69

Submerged 67.24 100.00 56.98 59.74 56.99

Average RSSI, in Percentage of Maximum RSSI, where σ is Standard Deviation

Average RSSI Lost, compared to Maximum RSSI

Conclusion

• Signals subject to large attenuation through water without waveform

• Waveform reduces signal somewhat in air• In water, PVC waveform reduces signal loss

by up to 10%• Submerged copper pipe subjects signal to

complete loss at 1m• Larger pipe diameters have a small, but

negative, effect on signal strength

Questions?

Background

Conclusion

Test Result Comparisons in Air

• Radio Frequency signals are commonly used in communications, from radio and cellphones to Wi-Fi

• RF signals lose strength quickly in water due to absorption/attenuation properties

• Wireless devices communicating with RF signals could be used in off-shore oil-drilling platforms, submarines, and marine life applications

Experiment Purpose

Test Result Comparisons in Water

Test Methods

Materials

Outcome

• Improvement in Radio Frequency signal propagation between a wireless transmitter/receiver pair through a pipe filled with air vs. RF signal propagation through water

• A hollow pipe can be used to propagate signal through air rather than water and could significantly improve the signal quality and transmission range

• Copper & PVC pipes of varying diameters cut into 1m segments

• Trash can filled with water

• RF Sensors operating at 2.4 GHz

• Transmit signal through pipe (copper & PVC) and two plastic bags in air• Transmit signal through pipe (copper & PVC) and two plastic bags by

placing pipe and plastic bags in water• Compare the RSSI percentage of copper, PVC and two plastic bags in air• Compare the RSSI percentage of copper, PVC and two plastic bags in

water• Use different diameter (1.5 inch, 2 inch, & 3 inch) of pipes to see

diameter’s effect on RSSI percentage

Average RSSI, in Percentage of Maximum RSSI, where σ is Standard Deviation

Average RSSI Lost, compared to Maximum RSSI

• Signals subject to large attenuation through water without waveform

• Waveform reduces signal somewhat in air

• In water, PVC waveform reduces signal loss by up to 10%

• Submerged copper pipe subjects signal to complete loss at 1m

• Larger pipe diameters have a small, but negative, effect on signal strength