Feasibility of Glucose Concentration Estimation in Whole Blood Samples Using Noninvasive Metamaterial Microwave Sensor

For a first time, 20 human blood samples with varying glucose concentrations using previously introduced metamaterial microwave (MTM) sensors, which have been already tested with phantoms. The MTM sensors based on composite right/left-handed (CRLH) metamaterial transmission line showed a detectable phase shift in the forward transmission parameter ( $\angle {S}_{{21}}$ ) which is related to the blood glucose concentration. Application of a novel biochemical approach introduces separate mathematical models based on gender, reflecting physiological difference in blood, which was further evidenced by measured variations in blood dielectric properties. This contributed to enhanced sensor performance as well as the professional sample preservation system. The accuracy of glucose concentration estimation was analyzed using mean absolute relative difference (MARD) and Parkes error grids. The MARD values for the female and male groups reached 23% and 29% respectively. The findings demonstrate the potential of the MTM sensor for noninvasive glycemia monitoring.