P13071 – Non-Invasive Blood Glucose Monitor Team Members Faculty Advisor Jared Bold Professor George Slack (EE) Yongjie Cao Customer John Louma Dr. Jayanti Venkataraman (EE) Andrew Rosen Dan Sinkiewicz
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 Roles Jared Andrew John - Microcontroller - Project Leader - Microcontroller programming configuration - Antenna design - Communication and testing - RF Simulation - Documentation - RF Path - Procurement - Calibration system Yongjie Dan - Schematic and - RF Path PCB layout - MATLAB development - PCB Population - Schematic
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
Level 1 Functional Block Diagram 3.0 Control Reset MIcrocontroller Resolution USB USB Harmonic RF Phase Plane Filters and Synthesizer Correction Gain Plot Transmitted Data Incident Incident Antenna (S21) Port Bi-Directional Antenna Choice Coupler (S11) Hard Drive Reflected Arm/Sample Math (Archive) Manipulation Reflected Reference Bi-Directional Coupler Transmitted Power Regulator Battery Vector Vector Pack Measurement Measurement (AD8302) (AD8302) Low Power Indicator
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 Initialize I/O and Power Up/Reset communication Measure Flag Calibrate Flag Sleep interfaces Microcontroller serves as Measurement Calibration done? Complete middleman for device - Reads the voltage Indicate to user outputs from the which RF path and load is being Set next frequency calibrated and collect mag and AD8302 phase data - Digitizes values and Set next frequency sends to PC via USB and collect mag and phase data Transmit data to PC Transmit data to PC
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 Antenna Design and Simulation
Components – Reflection Antenna Measured Return Loss
Components – Transmission Antenna Design and Simulation
Components – Transmission Antenna Measured 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 50 Ω 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
Input Impedance vs. Frequency 400 Real Imaginary 300 200 Impedance 100 0 -100 -200 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 Frequency (MHz) Return Loss (S11) vs. Frequency -2 -4 -6 -8 -10 S11 (dB) -12 -14 -16 -18 -20 -22 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 Frequency (MHz)
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
Recommend
More recommend
