Design and Experimental Validation of a Noninvasive Glucose Monitoring System Using RF Antenna-Based Biosensor

This article presents an end-to-end microwave-based system to detect the glucose level in aqueous solutions through a noninvasive scheme. A microwave signal is generated and transmitted through the sample under test (i.e., glucose-water solution). The received signal is then conditioned using a low-noise amplifier (LNA), a bandpass filter (BPF), and an RF detector. The change in the dc output voltage on the receiver side is used as a new way to detect the glucose level. The proposed glucose sensor is implemented using two RF microstrip patch antennas that resonate at 5.7 GHz and are fabricated using an FR-4 substrate. The design specifications of the sensing antennas are thoroughly studied and presented. The system is verified experimentally using glucose-water testing samples. The experimental results confirm the correlation between the glucose concentration and the dc output voltage for a concentration range of 0-5000 mg/dL. The effect of the transmitted power level on the system performance is also investigated. Finally, the proposed system is compared with the state-of-the-art systems reported in the literature.