Ověření parametrů MTM mikrovlnných senzorů pro neinvazivní měření koncentrace glukózy v krvi

Abstract

The dielectric properties of blood are affected by glucose concentration. Changing of these properties can be used to determine glycemia by using microwave sensors. Such a measurement would be non-invasive and would be very suitable for patients with diabetes mellitus.

This diploma thesis deals with the verification of an existing metamaterial microwave sensor for five subjects. Blood glucose levels of subjects were deliberately elevated by administering a solution of glucose dissolved in water, according to the used oral glucose tolerance test procedure. During the experiment, the S-parameters of the microwave sensor, the temperature around the sensor and the pressure applied to the sensor were measured. Simountaneously with these parameters, blood glucose was measured by invasive continuous system and a conventional glucometer. The phase change $\varphi$ of the measured parameter $S^*_{21}$ was used for data evaluation. The evaluated data showed that under the real conditions the measurement is affected by several negative effects, such as sweating of subjects, pressure on the sensor, the temperature of the microwave sensor itself, due to which it is not possible to safely determine blood glucose concentration by phase change, at least for the proposed measuring arrangement.