Sensitivity Enhancement of an Inter-Digital Sensor for High Precision Glucose Monitoring

Over the past decade, planar microwave sensors have demonstrated their versatility across various applications, including glucose sensing. Among these, inter-digital sensors have garnered significant attention due to their uncomplicated structure, adaptability for fabrication on flexible substrates, and cost-effectiveness. Despite their relatively high sensitivity, they fall short of meeting the requirements for biomedical applications, emphasizing the need for sensitivity enhancement. This paper introduces a straightforward yet impactful sensitivity enhancement method employing single-transistor active circuitry. The application of this circuitry enhances the sensitivity of an inter-digital capacitor from 0.015 pF/mM/L. for glucose concentration to 1.5 pF/mM/L., proving suitable for numerous biomedical applications, notably glucose monitoring. Theoretical analyses, simulations, and experimental results verify the effectiveness of the proposed method.