Abstract

Researching the RF application of noninvasive continuous, real time, blood glucose monitoring has been a persistent topic of interest for the research group at the electromagnetic theory and application (ETA) lab at RIT. The technique is based on the effects of glucose on the dielectric properties of blood. When the dielectric permittivity of the tissue changes due to glucose, the resonant frequency and input impedance of an antenna sensor can be related to the change in glucose level, as shown in [1] and [2]. The feasibility of this technique has been demonstrated successfully with one diabetic and one non-diabetic patient in [3].

The goal of this work is to utilize the existing developments to create a robust automated system to be used in clinical trial in a hospital setting. The system has been designed to make real time measurements of blood glucose and remotely monitor the data through a cell phone app. The clinical trial will consist of on-body antenna sensor measurements, and dielectric permittivity measurements of in-vitro blood samples contaminated by glucose. Four different phases are mapped out focusing on consistency, correlation, data collection and accuracy verification. The clinical trial will consist of on-body antenna sensor measurements, dialectic permittivity measurements of blood and traditionally measured blood glucose values. Developing a relationship between these measurements will lead to an algorithm for determining the blood glucose level of a patient.

Utilizing existing designs, the antenna sensor is a planar monopole antenna with an artificial magnetic conductor design from [5]. The sensor assembly is a more robust antenna than that which was previously constructed with an AMC layer. The sensor is designed to be insensitive to patient movement because the stability of the sensor is critical for performance in the clinical trial. Simulations have also been performed with a human body model in HFSS to ensure that the Specific Absorption Rate (SAR) levels conform to FDA regulations for biomedical applications. Antenna sensors of each design were fabricated and tested to show an agreement with simulation results for both the resonant frequencies and radiation patterns.

An automated measurement system has been developed using MATLAB App Designer to be compatible with bench top Agilent network analyzers as well as the small and portable R140 network analyzer from Copper Mountain Technologies. The application is capable of recording S-parameter measurements and doing real time analysis, as well as uploading the data to an RIT server. Once the processed data is on the server, it can be accessed immediately over the internet by a different computer or a smartphone application. A MATLAB app was designed for monitoring the data remotely and a smart phone application was also developed for the same purpose.

The clinical trial will also include an in-vitro study where permittivity measurements will be collected of blood samples containing glucose. In order to support the antenna sensor measurements, a correlation will be obtained from the in-vitro samples between the dielectric permittivity and the concentration of glucose. The dielectric probe has been automated in preparation for the trial.

In order to prepare the system for use in clinical trials, extensive testing using an experimental test setup was carried out. The test setup incorporated both the antenna sensor and the dielectric probe to make measurements of water and glucose. With the antenna close enough to the dish and the dielectric probe in the water, both the antenna sensor response and the relative permittivity of the water are observed to change when the concentration of glucose in the dish changes. This combined testing will be imitated in the clinical trial when the antenna sensor is used on a patient’s body and permittivity measurements are made of in-vitro blood samples.

Library of Congress Subject Headings

Blood sugar monitoring--Technological innovations; Dielectric measurements--Automation; Biosensors--Testing

Publication Date

5-3-2021

Document Type

Thesis

Student Type

Graduate

Degree Name

Electrical Engineering (MS)

Department, Program, or Center

Electrical Engineering (KGCOE)

Advisor

Jayanti Venkataraman

Advisor/Committee Member

Gill Tsouri

Advisor/Committee Member

Panos Markopoulos

Campus

RIT – Main Campus

Plan Codes

EEEE-MS

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