Design of a microwave sensor for non-invasive blood glucose monitoring.

Abstract

Diabetes is one of the most prevalent chronic diseases. The exponential rate of increase in the number of diabetics urged researchers to search for new methods of measuring blood glucose continuously and non-invasively. The ability of microwave devices to extract the electrical parameters of material accurately and without direct contact, makes them ideal for measuring glucose concentrations non-invasively. Therefore, since the past decade, a lot of research work has focused on designing microwave sensors that are capable of sensing the variation of glucose in blood. Although some of the proposed devices have shown good sensitivity, however none of them is accurate enough to replace the currently used glucometers. This thesis addresses the design of non-invasive glucose sensors by relying on microwave based components. Hence, the design of various types of radio frequency (RF) circuits is presented to tackle this challenge. The behavior of the proposed RF circuits as glucose sensing systems is tested using simulation in addition to in-vitro, ex-vivo and in-vivo studies. A good correlation between the scattering parameters of proposed sensors and the variations in glucose levels is attained. Several regression models are also developed and applied on the collected data, where a selection of the optimal model with the least prediction error is identified. Examined results using the Clarke error grid demonstrate that 100percent of the predicted glucose levels lie within the clinically acceptable regions for the various proposed sensors.