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.