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P13071 – Non-Invasive Blood Glucose Monitor
Team Members Jared BoldYongjie CaoJohn Louma
Andrew RosenDan Sinkiewicz
Faculty Advisor
Professor George Slack (EE)
Customer
Dr. Jayanti Venkataraman (EE)
Overview
• Develop a non-invasive real time monitoring system that measures blood glucose
• Improve the accuracy of current non-invasive measurement system
• Obtain a transmission signal and perform a vector measurement
Team RolesJohn- Microcontroller
configuration- RF Simulation- Procurement
Yongjie- Schematic and
PCB layout- PCB Population
Jared- Microcontroller
programming- Communication- Documentation
Dan- RF Path - MATLAB development- Schematic
Andrew- Project Leader- Antenna design
and testing- RF Path - Calibration
system
Project Needs and Specs
Customer Need Customer Specification
Accurate measurement of resonant frequency Accurate to 15 KHz of network analyzer
Calibration System Calibration time of < 60 seconds
Reflection Antenna Narrow band, with resonant frequency ≈ 1.1 GHz
Transmission Antenna Wide band, with minimum bandwidth from 800 MHz to 2 GHz
High resolution data Measurement intervals of < 60 seconds
Verify antenna performance in real-time Display resonant frequency and sweep data is it is aquired
System Architecture
3.0 Control
USB
Battery Pack
Power Regulator
Hard Drive(Archive)
Plot Data
Math Manipulation
Port Choice
USB
Level 1 Functional Block Diagram
Resolution
MIcrocontroller
Arm/Sample
RF Synthesizer
Antenna (S11)
Vector Measurement
(AD8302)
Antenna (S21)
Vector Measurement
(AD8302)
Harmonic Filters and
Gain
Inci
dent
Inci
dent
Tran
smitt
ed
ReferenceReflected
Transmitted
Refle
cted
Reset
Bi-Directional Coupler
Bi-Directional Coupler
Low Power Indicator
Phase Plane Correction
Concepts – Measurement System
• Critical to operation of device- Generated the RF signal
at the desired frequency- Ensured the signal
reaches antenna with maximum power and minimum error
- Measures the reflected and transmitted signal
Concepts – Data Acquisition
Power Up/ResetInitialize I/O and communication
interfacesSleepMeasure Flag Calibrate Flag
Measurement done?
Set next frequency and collect mag and
phase data
Transmit data to PC
Calibration Complete
Indicate to user which RF path and
load is being calibrated
Set next frequency and collect mag and
phase data
Transmit data to PC
Microcontroller serves as middleman for device- Reads the voltage
outputs from the AD8302
- Digitizes values and sends to PC via USB
Concepts – Data Analysis and Display • MATLAB Measure Command flow chart
• Reads continuous stream of data from device and stores/displays the data in real-time.
Concepts – Data Analysis and Display • MATLAB Calibration Command flow chart
• Reads continuous stream of data from device and stores off the calibration data to be used later to compensate for phase error in measurements
Components – Reflection AntennaDesign and Simulation
Components – Reflection AntennaMeasured Return Loss
Components – Transmission AntennaDesign and Simulation
Components – Transmission AntennaMeasured Return Loss
Components and Layout
• RF Synthesizer – ADF4351 • Vector Measurement – AD8302• Microcontroller – MSP430F5427A
Testing
Component/System Testing
• Individual testing of each system• Verification of power supply and regulation• Communication between MCU and USB• Communication between board and host PC• Communication between MCU and RF Synthesizer• Continuity of RF path and verification of components• Correct output of when using test signals on the AD8302• Verification of correct frequency output of RF Synthesizer with spectrum
analyzer
Device Testing
• Test free space resonant frequency• Test against sugar water
• Three different levels of sugar concentrations• Solution is comprised of Water = 66.9%, Salt = 0.8%, Sugar = 25%, Flour = 7.3%
• Test against human body• Use fast acting glucose tablets to raise blood-glucose• Compare with real blood glucose monitor• Find a diabetic to make one final test
Results
Success or Failure?
• Overall, the device was designed to meet/exceed the specifications given
• All aspects of the device function individually, however the design ultimately does not function. The board was not matched to 50Ω at our designed frequency of 1.1 GHz, making it impossible to determine the resonant frequency of the antenna.
• We didn’t anticipate the shift in impedance and we could have resolved the issue with some sort of tuner
800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000-200
-100
0
100
200
300
400Input Impedance vs. Frequency
Frequency (MHz)
Impe
danc
e
800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000-22
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2Return Loss (S11) vs. Frequency
Frequency (MHz)
S11
(dB
)Real
Imaginary
Matlab GUI
Suggestions for Future Work – Advice to next group• Have a dedicated QA person for each system of the device• Ensure that at least one member of the team has RF circuit board
design experience• Design the board for a smaller bandwidth
• Get the development boards for everything, regardless of cost• Develop a working product with dev boards and antenna. Then make PCB.
• Buy doubles/extras of all components• Develop standards for testing procedure
Opportunities for Improvement
• Properly matched RF path• Make path simpler to remove parasitic effects from chips
• Implementation of a more robust calibration system• Calibrate out magnitude and phase
• Enhanced communications between MATLAB and device• On board processing• 360⁰ Phase measurement using two AD8302s