A Tunable Wearable Band Reject Sensor for Enhanced Glucose Monitoring Sensitivity

Abstract

This paper presents a non-invasive glucose-monitoring sensor that is based on a tunable band reject filter. The filter topology comprises a feeding network at a top layer that excites eight open loop resonators embedded in the ground plane. The shape of the resonators is inspired by the vasculature anatomy of a human arm. The embedded resonators are designed to resonate at 8 different frequencies in order to track the variations of the glucose level across the 1.5 GHz - 2.4 GHz frequency span. Furthermore, the filter's frequency operation is also tuned by relying on integrated varactors in order to enhance the sensor's dynamic responsiveness to glucose variations. The proposed tunable filter is fabricated and tested on diabetic rats, and in a clinical setting. A high correlation between the scattering parameters of the proposed sensor and the variations in glucose levels is noted. A Gaussian Process regression model is also developed using data obtained from experiments. Results demonstrate that the proposed sensor detects glucose variation with an accuracy that reaches 98.55% well within clinically acceptable performance.