P13071: Non-Invasive Blood Glucose Monitor System Level Design Review

Jared Bold, Yongjie Cao, John Louma, Andrew Rosen, Daniel Sinkiewcz S21 Antenna

Device Under Test (DUT)

Cable to LabVIEW

KGCOE MSD

Technical Review Agenda

P13071: Non-Invasive Blood Glucose Monitor Meeting Purpose: 1. 2. 3. 4. 5.

Overview of project Confirm Customer needs and Specifications Review variety of concepts designs Propose our selected design Generate new ideas

Materials to be Reviewed: 1. 2. 3. 4. 5. 6. 7. 8.

Project Description and Objective Work Breakdown Structure Customer Needs Customer Specifications Functional Decomposition Concept selection process Risk Assessment Project Plan

Meeting Date: April 5, 2013 Meeting Location: Room 09-4435 Meeting time: 10:00 – 11:30 AM Timeline: Meeting Timeline Start time 10:00 10:10 10:15 10:25 10:35 10:55 11:10 11:20

Topic of Review Introduction for the Project Work Breakdown Structure Customer Needs Customer Specifications Functional Decomposition and Block Level Diagrams Concept Development and Chosen Design Risk Assessment Project Plan

KGCOE MSD

Page 1 of 2

Required Attendees Prof. Slack, Dr. Venkataraman Prof. Slack, Dr. Venkataraman Prof. Slack, Dr. Venkataraman Prof. Slack, Dr. Venkataraman Prof. Slack, Dr. Venkataraman Prof. Slack, Dr. Venkataraman Prof. Slack, Dr. Venkataraman Prof. Slack, Dr. Venkataraman

Technical Review Agenda

Project Description

.

Project Background: Blood glucose monitoring is a valuable tool not only used by diabetic individuals to maintain a healthy lifestyle, but also by physicians caring for patients. Today's accurate monitoring systems are invasive, requiring direct access to a patient's blood for accurate analysis. The blood glucose meter pricks the finger in order to obtain a drop of blood from which a discrete glucose level can be determined. Continuous glucose measurements can be obtained by placing a glucose sensor subcutaneously, which delivers measurements to an external system. There is a distinct lack of noninvasive glucose monitoring alternatives that can provide the same level of accuracy.

Problem Statement: Develop a non-invasive real time monitoring system that measures blood glucose. The system should use a microstrip antenna to measure reflection and transmission of a synthesized signal. These measurements should be comparable to a network analyzer.

Expected Project Benefits: Current blood glucose monitors are invasive and discourage multiple measurements. There are many benefits to having a well designed noninvasive blood glucose monitor. It will allow patients to continuously monitor their blood glucose and will encourage the patients to monitor their levels more often. The system will also allow for data archival, so a history of blood glucose levels can be analyzed.

Core Team Members:     

Jared Bold Yongjie Cao John Louma Andrew Rosen - Project Manager Dan Sinkiewicz

Strategy & Approach

.

Assumptions & Constraints: Objectives/Scope:    

Improve accuracy of current noninvasive glucose monitoring system Provide a method of real time monitoring of patient's blood glucose levels Archive measurement data for future analysis Obtain a transmission signal and perform a vector measurement

Deliverables:    

Issues & Risks

Improved accuracy of reflection vector measurements Compact printed circuit board layout Introduce calibration system to further increase accuracy measurements Visual representation of data through LabVIEW graphical user interface

KGCOE MSD

The team will use a two antenna system to measure both the transmission and reflection coefficients of the user's limb. The system must be designed to minimize undesired effects on the antenna system, such as coupling. A calibration system for the measurement circuit will be designed to improve measurement accuracy. The data must be processed and displayed through LabVIEW and compared real time to automated Network Analyzer measurements to verify accuracy.

   

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Difficulty measuring transmission through arm The antennas might couple or the "creeping wave" effect could alter measurements Peripheral devices could be difficult to integrate successfully Patient could be at risk of slight shocks if the system short circuits

Technical Review Agenda

Summary of Ben Freer’s Thesis The present work on blood glucose monitors focuses on the possibility of a monitor that non-invasively measures blood glucose levels using electromagnetic waves. The technique is based on relating a monitoring antenna’s resonant frequency to the permittivity and conductivity of blood which in turn is related to the glucose levels. Using the Agilent 85070E dielectric probe and an Agilent 8720B network analyzer, the dielectric permittivity and conductivity of twenty different blood samples was measured over a frequency range of 1GHz – 10GHz. The Cole-Cole model was modified through curve fitting to in-vitro data that includes a factor representing glucose level. The desired frequency sweep range for the monitor was then determined to be 200MHz to 2GHz. An antenna was been designed, constructed and tested in free space. A simulation model of layered tissue and blood together with an antenna was created to study the effect of changing glucose levels. It is noted that the antenna’s resonant frequency increases with increase in glucose levels. An analytical model for the antenna was developed, which was validated with simulations. A measurement system was developed to measure the resonant frequency of the antenna. A frequency synthesizer generates an RF signal over the desired frequency range of 200MHz to 2GHz. This signal is sent to the antenna through a directional coupler that generates forward and reflected signals. These voltages are measured and the reflection coefficient is calculated with a microprocessor. As an experimental verification, two antennas were strapped one on each leg of a patient with one antenna connected to the PNA and the other to the measurement system. As the patient ingested fast acting glucose tablets, the blood glucose level was measured by a traditional glucose meter. At the same time, a comparison of the resonant frequency of the antenna measured by the PNA and by the measurement system showed good agreement. Further, it is seen that the antenna resonant frequency increases as the glucose level increases, which is consistent with the simulation model.

Non-Invasive Blood Glucose Monitor

Data Collection

Power System Regulation

Power Source

Battery Pack

Calibration

Measure open, short, load, through

Voltage Regulation

3.3/5V

Short Protection

Low Power Mode/ Indication

Transfer/store reference points

Calibration command

Data Analysis

Data Measurement

TX RF Signal (PLL)

Scale Signal

Filter RF Signal

RX RF Signal (S11) (REFLECTION)

RX RF Signal (S21) (TRANSMISSION)

Transmit Phase and Magnitude change to μController

Filter RX Signal

Filter RX Signal

ADC

Determine Change in Phase and Magnitude

Determine Change in Phase and Magnitude

Store

Transmit to computer

Labview GUI

Calculate resonant over time

USB

Plot Data

Archive Data

Andrew Rosen -Project Manager

Measurement System

Vector Measurement

RF Path

Power Unit

Antenna

Dan Sinkiewicz

John Louma

Andrew Rosen

John Louma (backup)

Andrew Rosen (backup)

John Louma (backup)

PCB Layout

Yongjie Cao

Jared Bold (backup)

RF Transmission S11

Computer

Microcontroller

Dan sinkiewicz

Jared Bold

Andrew Rosen (backup)

John Louma (backup)

RF Transmission S21

John Louma

Yongjie Cao

Yongjie Cao (backup)

John Louma (backup)

Revision #: Customer Need #

Importance

CN1 CN2 CN3 CN4 CN5 CN6

5 5 5 3 5 4

CN7 CN8 CN9

5 5 3

CN10 CN11 CN12 CN13

4 5 5 2

CN14 CN15

5 5

CN16 CN17 CN18 CN19

4 2 3 4

Description Measurement System More accurate resonant frequency measurement Perform frequency sweep Calibration System Incorporate dual antenna system Verify antenna performance in real time Resolution (time) Microprocessor Data Handling Communication with PC Controlling frequency sweep Resolution (bit size) PC Data Analysis Parse data Real time update Display data Archive data Physical Attributes Compact PCB Non-invasive Functionality Battery power Low power notification Ergonomic fit on a limb Power conservation

Comments/Status Explore other options Other synthesizers? Short, open, load Measure transmitted and reflected signals Labview and network analyzer Sample rate Wired VS. wireless

Labview Labview Labview

Portable Arm or leg? Low power when not used

Cust. Need #: enables cross-referencing (traceability) with specifications Importance: Sample scale (1=must have, 2=nice to have, 3=preference only), or see Ulrich exhibit 4-8. Description: organize as primary and secondary needs (hierarchy) -- Ulrich exhibit 4.8 Comment/Status: allows tracking of questions, proposed changes, etc; indicate if you are meeting the need ("met") or not ("not met")

Spec. #

Importance

Source

Function

Specification (metric)

Unit of Measure

Measurement System Antenna Performance Accuracy of measurement system compared to Network Analyzer KHz Power absorbtion Power of transmitted signal mW Frequency Sweep Check for resonant frequency between 200 MHz and 4 GHz MHz Calibration Time required for calibration Seconds Resonant Frequency Determination Bandwidth of Narrowband Antenna MHz Resonant Frequency Determination Bandwidth of Wideband Antenna MHz Power absorbtion return loss of Narrowband Antenna dB Power absorbtion return loss of Wideband Antenna dB Phase change Max phase change degrees Sampling Intervals between measurements Seconds Microprocessor Data Handling S11 3 CN7 Data Transmission Time required for packet transmission Seconds S12 3 CN9 Analog to Digital Converter Bit resolution Bits S13 5 CN11 Update Time Time between microprocessor transmission and data display Seconds PC Data Analysis S14 2 CN12 Data Display Amount of data points Data Points S15 2 CN13 Data Storage Amount of data stored Bytes Physical Attributes S16 3 CN14 Printed Circuit Board Layout Size Inches Functionality S17 3 CN16 Power Source Battery Voltage Volts S18 3 CN17 Low Power Notification Time before battery death Minutes Spec. #: enables cross-referencing (traceability) and allows mapping to lower level specs within separate documents Source: Customer need #, regulatory standard (eg. EN 60601), and/or "implied" (must exist but doesn't have an associated customer need), constraint Description: quantitative, measureable, testable details *This table can be expanded to document test results S1 S2 S3 S4 S5 S6 S7 S8 S9 S10

5 5 4 5 4 5 4 5 4 3

CN1 CN4 CN2 CN3 CN4 CN4 CN4 CN4 CN4 CN6

Marginal Value

Ideal Value

15 200 200-4000 60 15 200-2000 -20 -20 180 60

10 150 200-2000 1 10 100-3000 -15 -15 180 15

2ms 10 10ms

1us 16 8ms

20 1MB

240 1KB

3x3

Less than 3x3

5 30

3.3 5

Comment s/Status

P13071 Non-Invasive Blood Glucose Monitor Level 0 Functional Block Diagram

Reset

Non-Invasive Blood Glucose Model

Data to computer

Resolution

Incident Signal

Reflected Signal

Transmitted Signal Device Under Test (DUT)

Computer ( LabVIEW)

P13071 Non-Invasive Blood Glucose Monitor Level 1 Functional Block Diagram

Physical Button

MIcrocontroller USB

USB Resolution

Plot Data

Port Choice

Reflected

Reference

Transmitted

Antenna (S11)

Incident

Directional Coupler

Reflected Incident

RF Synthesizer

Hard Drive (Archive)

Math Manipulation

Antenna (S21)

Arm/Sample

Directional Coupler

RF Splitter

Reference Reference

Open, Short, Load, Through

Vector Measurement (Scattering Matrix)

Vector Measurement (Scattering Matrix)

Power Regulator

Battery Pack

Microcontroller Level 0 Functional Block Diagram

POR (Power-on Reset)

Calibrate RF Path

Transmit Calibration Data to Host

Initialize Synthesizer

Enter Low Power Mode

No Send S Matrix to PC / Store S Matrix in Flash

Measure S21

Transmit Synthesizer Signal

Measure S11

Sweep Complete?

Begin sweep command from PC?

No Reset

Enter Low Power Mode

Stop

No Brown Out Sweep Interval Timer Expired

Yes

P13071 Non-Invasive Blood Glucose Monitor Screening - GUI

Selection Criteria USB interface Ease of programming Ease/ability to Interface with peripherals Familiarity

Sum + 's Sum 0's Sum -'s Net Score Rank Continue?

Concepts C

A

B

D

E On board Screen/processing

Matlab

C++

Mobile Platform

(Reference) LabVIEW

0

0

-

D

-

+ 0 +

+

-

A T U M

-

2 2 0

1 1 2

0 0 4

0 0 0

0 0 4

2 1

-1 3

-4 4

0 2 Yes

-4 4

P13071 Non-Invasive Blood Glucose Monitor Screening - RF Synthesizer

A VCO Selection Criteria Frequency range Deviation from set frequency small footprint Input signal

B

Concepts C D Crystal Reference PLL

E DDS

G RF Mixer

-

-

d

-

-

0 0

+ +

a t u m

0 0 0

0 0 -

0 3 1

0 2 2

-1 3 No

-2 4 No

d a t u m

Sum + 's Sum 0's Sum -'s Net Score Rank

0 2 2

Continue?

-2 5 No

2 0 2 0 No

0 2 No

0 1 Yes

P13071 Non-Invasive Blood Glucose Monitor Screening - Calibration

A Mux with on chip loads Selection Criteria Automated Ease of implementation Programming complexity Calibration Usability Space required

Sum + 's Sum 0's Sum -'s Net Score Rank Continue?

Concepts B External loads

C

D (Reference) None

+

0

D

+ +

+ 0 + -

A T U M

3 0 3 0

2 2 2 0

0 0 0 0

Yes

No

No

P13071 Non-Invasive Blood Glucose Monitor Screening - Communication Interface

Selection Criteria Power Usage during transmission Power Usage during idle Transfer speed Power Supply Error rate Distance of communication Ease of implementation Cost to implement Space to implement Ease of computer interface

Concepts C D Zigbee RS-232 (Ben's Thesis)

A USB

B Bluetooth

+

+

+

d

0

+

+

a

+

+

+

t

+

0

0

u m

0

-

-

0

0

0

0

0

0

d

-

-

-

a

-

-

-

t

-

-

-

u m

Sum + 's Sum 0's Sum -'s Net Score Rank Continue?

3

3

3

0

4

3

3

10

3

4

4

0

0

-1

-1

0

1

4

3

2

Yes

No

No

No

E

G

P13071 Non-Invasive Blood Glucose Monitor Screening - Processor

Selection Criteria I2C UART SPI USB ADC Flash Memory Clock Speed GPIO

Sum + 's Sum 0's Sum -'s Net Score Rank Continue?

A

B

MSP430

Stellaris ARM

0 0 0 0 + 0 0 -

Concepts C

D

E

G

C2000

Reference PIC

Hercules ARM

0

0

D

0

0

0 0 + -

0 0 0 0 + -

A T U M

0 0 + + -

0 0 -

1 6 1

1 3 4

1 5 2

0 0 0

2 3 3

0 3 5

0 1 Yes

-3 3 No

-1 2 No

0 1 No

-1 2 No

-5 4 No

Arduino

P13071 Non-Invasive Blood Glucose Monitor Screening - On Device Storage Concepts

Selection Criteria Storage Size Storage Speed Ease of Access Ease of Implementation Cost

Sum + 's Sum 0's Sum -'s Net Score Rank Continue?

A

B

C

D

E

Removable SD card

uC Flash

Flash mem chip

(Reference) None

Flash drive

+ + 0 -

+ + 0 0 0

+ + 0 -

D A T U M

+ + 0 -

2 1 2

2 3 0

2 1 2

0 0 0

2 1 2

0 2 No

2 1 Yes

0 2 No

0 2 No

0 2 No

P13071 Non-Invasive Blood Glucose Monitor

A Patch

B Dipole

0

0

0

D

0

+ + +

+ +

0 -

A T U M

+ + -

Selection Criteria size groundplane bandwidth ease of design

Screening - Microstrip Antenna Designs Concepts C D vivaldi Reference planar inverted f

E Bowtie

D A T U M

Sum + 's Sum 0's Sum -'s Net Score Rank Continue?

3 1 0

2 1 1

0 2 2

0 0 0

2 1 1

3 1 Yes

1 2 No

-2 5 No

0 3 No

1 4 No

1 2 3 4 5

Effect

Cause

Compensating for Electrical Delay

Calibration won’t be accurate

Calibration

2

2

Transmission through arm won’t work Coupling between antennas Noise being introduced in Channel

Inability to measure S21 Accuracy of measurement S11, S21 Bad measurement of S11, and S21 Lengthen/restrict resolution Peripheral devices won’t perform as intended

7

Synthesizer lock time Peripheral configuration issues Dielectric gel could affect measurement

8

Patient electrocution

Could harm patient

9 10

Program hangup Not accurate reference signal

Loss of functionality S11 and S21 will not be correct

12

PCB layout

13

Directional coupler

6

Likelihood scale 1 - This cause is unlikely to happen

Could shift resonance

Arm causes too much attenuation Antennas are place too close together Movement, body type, environment Switch time on synthesizer Inappropriately set registers Dielectric not modeled properly Short power to device Poor programming RF splitter doesn’t work Not knowing how to do an RF pcb

Importance

Risk Item

Severity

ID

Likelihood

MSD Project Risk Assessment

10

Action to Minimize Risk

Owner

Develop a check in code to adjust for electrical delay

Andrew

3

3

5

2

3

10

Use appropriate power in design for microwave sensors Place device in area this is unlikely to occur

3

2

9

Designed to reduce transience

Jared

1

1

6

Synthesizer choice

Dan

2

3

10

Dev boards for all peripherals

Dan

1

2

8

Research dielectric gel

Andrew

1

2

10

Power isolation

Yongjie

1

3

10

Spend time reviewing code

John

1

3

10

Validate power splitter

Andrew

Andrew Andrew

Not working at right freq

Severity scale 1 - The impact on the project is very minor. We will still meet deliverables on time and within budget, but it will cause extra work

2 - This cause could conceivably happen 3 - This cause is very likely to happen

2 - The impact on the project is noticeable. We will deliver reduced functionality, go over budget, or fail to meet some of our Engineering Specifications. 3 - The impact on the project is severe. We will not be able to deliver, or what we deliver will not meet the customer's needs.

“Importance Score” (Likelihood x Severity) – use this to guide your preference for a risk management strategy Prevent Action will be taken to prevent the cause(s) from occurring in the first place. Reduce Action will be taken to reduce the likelihood of the cause and/or the severity of the effect on the project, should the cause occur Transfer Action will be taken to transfer the risk to something else. Insurance is an example of this. You purchase an insurance policy that contractually binds an insurance company to pay for your loss in the event of accident. This transfers the financial consequences of the accident to someone else. Your car is still a wreck, of course. Accept Low importance risks may not justify any action at all. If they happen, you simply accept the consequences.