Non-Invasive Glucose Detection Using a Triple Cell Square CSRR Sensor: Experimental Validation

In this paper, a microwave biosensor for the non-invasive detection of blood glucose levels is designed. The proposed sensor, sized
$55.6 \mathrm{x}20\mathrm{x}1.5 \text{mm}^3$
, consists of three cells of square complementary split ring resonators. The proposed sensor is placed on top of an FR4 dielectric substrate. The sensor elements are excited via a coupled 50-ohm microstrip line etched on the bottom side of the substrate. The HFSS has been used for the design and parametric analysis of the proposed Triple Cell Square Complementary Split Ring Resonator (TC-SCSRR). The fabricated sensor is validated by In Vitro experiments in which de-ionized aqueous glucose solutions of different concentrations (70 mg/dL - 1000 mg/dL) are used. A shift of the resonant frequency of transmission response is observed due to the change in input impedance, caused by different levels of glucose in aqueous solutions. The results revealed high sensitivity of the proposed sensor. The high sensitivity, size, and sensing range of operation make the proposed TC-SCSRR a promising candidate for the handheld non-invasive blood glucose monitoring device.