High-sensitivity microwave resonator sensor for aqueous glucose detection using field-concentrating elements

Abstract

In this article, we present a highly sensitive microwave sensor for determining the concentration of aqueous glucose solutions in the microwave regime. The proposed sensor is based on a single split-ring resonator (SRR) printed on a Rogers RO3003 substrate and operates at 2.9 GHz. The sensitivity of this sensor is enhanced by using a narrow gap of approximately 100 µm, which increases the capacitance of the SRR and, more importantly, produces a localized field enhancement within the gap region. Moreover, the proposed design operates with only 2 µL of sample, a notable improvement over sensors that typically require larger liquid volumes. Both the simulation and measurement results showed a clear linear shift in the resonance frequency over a concentration range of 0–400 mg/dL, with the ability to detect minimal concentration variations as small as 50 mg/dL. These results confirm the effectiveness of the sensor for noninvasive glucose detection and represent a significant advancement in the field of microwave sensing.

This work was supported in part by the Generalitat de Catalunya and European Regional Development Fund (FEDER) under Grant PDR2014-2022/56-30157-2021-2A, Grant 2021 SGR 01415 Q0818003F, and Grant Metropolis PLEC2021-007609; in part by the Agencia Estatal de Investigación, Spain, under Grant CICYT PID2019-107885GB- C31, PID2022-136869NB-C31 MICIU / AEI / 10.13039 / 501100011033/ FEDER, UE, and Grant Prueba de Concepto PDC2022-133091-I00; and in part by the Next Generation EU. Additionally, this work is supported by the CNRST as part of the ”PhD-Associate Scholarship– PASS” Program.

Peer Reviewed

Postprint (author's final draft)