biosensor networks

Biosensor Networks

Principal Investigators: Frank Merat, Wen H. KoTask Number: NAG3-2578

Case Western Reserve UniversitySeptember 18, 2002

NASA SpaceCommunications Symposium

Biosensor Networks

Project Overview

The goal of this project is to develop a test platform for biomedical monitoring using COTS components and state-of-the-art communications concepts. Start date March 2001.

Body drawing from Fundamentals of Bioelectrical Impedance Analysis, Rudolph J. Liedtke, RJL Systems, February 1998.

RF SourceSpectrum Analyzer

Biomonitoring NetworkComputer Medical

Data Logger/Analysis Station

Conventional RF Link (BlueTooth?)

IntraBody Wireless Network

IntraBody/Extrabody Wireless Network

Router

Biosensor Networks

Enterprise Relevance

This technology has applications for continuous health monitoring of humans in space and for long duration space experiments involving humans and/or animals.Any wireless solution should interface with existing and future proximity networks.

“A Lightweight Ambulatory Physiological Monitoring System,” NASA Tech Briefs, January 2001.

Biosensor Networks

Enterprise Impact

The major impact of this technology is upon manned missions, e.g., space station and shuttle missions .

Removal of wires and other encumbrances would improve astronaut freedom of movement and increase the system reliability.

Wireless Biosensor Network

Biosensor Networks

Milestones - Technical Accomplishments and Schedules

Due Date Milestone Description Tech Accomplishments

1 April 2002 Characterize human body as communications channel for rf.

Communications through human body.

Schedule Status Schedule Deviation

Completed none

Feasibility Experiment

Body drawing from Fundamentals of Bioelectrical Impedance Analysis, Rudolph J. Liedtke, RJL Systems, February 1998.

RF SourceSpectrum Analyzer

Biosensor Networks



2 June 2002 Design antennas for coupling to human body.

Designed and measured multiple patch antennas. Verified antenna performance with loop antennas and published literature.


Completed none

Biosensor Networks

Milestones - Characterize human body as rf communications channel

Received Power Through the Body (underside of forearm with 30 cm separation). Antenna dimensions: L =39 mm, W = 42

mm, and h = 0.062” on FR-4 substrate.

Received Power at 50 cm separation.Transmitter antenna: L = 54 mm, W = 48 mm, h = 0.062”; receiver antenna L = 26

mm, W = 38 mm, h = 0.062”, both on FR-4 substrate.

Geometry of Basic Rectangular Patch Antenna

Received Power at 1 m separation. Antenna dimensions are L = 41 mm, W = 38 mm, and h = 0.062” on FR-4 substrate.

Biosensor Networks



4 August 2002 Develop software to transmit data and network nodes.

Completed development and testing of prototype system.


Completed none


3 August 2002 Design prototype wireless nodes for collecting and transmitting sensor data through human body.

Completed fabrication and testing of prototype nodes.


Completed none

Biosensor Networks

Prototype sensor node

Typical rectangular center fed patch antenna used for testing.

Bare PC board for prototype

Prototype sensor node with integrated antenna and D-socket for programming

“early” power for prototype

Antenna board for prototype

Biosensor Networks

Risks

Risk Impact Resolution Plan

1 EMI from radiated signals not confined to human body.

Would restrict application of technology, especially in space missions.

Reduce transmitter power.

2 Antenna size is too large.

Would restrict application of technology

Shift to higher operating frequency

3 Wireless nodes consume too much power.

Increases size of wireless modules.

Redesign electronics using newer COTS technology or semi-custom design.

Biosensor Networks

Funding Issues

Phase one funding ended on budget.Phase two funding through March 2003.

Biosensor Networks

Future Plans

Event Goals

1 Biomedical sensor survey Determine COTS biomedical sensors suitable for a personal biosensor network.

2 Antenna testing Optimize antenna dimensions for biosensor network. Impedance match antenna to electronics.

3 Functional prototype Demonstration prototype.

4 Modeling of rf propagation in human body.

Conventional radiation and transmission line models do not explain observed behavior. A better model (perhaps including ionic conduction) would allow better prediction of system performance and optimization of antenna.

Biosensor Networks

Propagation modeling

Simulation of Transmission Line Model for 0.6 Meters Antenna Separation

Transmission Line Model of Antenna/Human Circuit using experimentally measured antenna parameters and

published values for the electrical parameters of the human body

Biosensor Networks

Papers and Awards

[1] M. Dummeruth. Wireless Wearable Health Monitoring System. M.S. Thesis, Case Western Reserve University, August 2002. (Advisor: F. Merat).

biosensor networks

Documents