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