Dielectric Models for the Accurate Design of Wearable Diabetes Sensors

The accurate design of wearable sensors to be adopted for biometric applications is strongly dependent on a reliable characterization of the electromagnetic properties relative to the involved biological tissues, which determines the validity of the relationship between the sensor response and the behaviour of the bio-parameter to be monitored. In the present contribution, an overview of current models describing the complex permittivity behaviour of biological media, with a specific focus on blood plasma and thus on diabetes pathology, is presented. In particular, specific drawbacks are highlighted which inherently limit the reliability of the wearable sensors design. Furthermore, an improved dielectric model, properly considering the variation of both dielectric constant as well as tangent loss factor relative to blood plasma is presented and discussed, by demonstrating the strong enhancement in the prediction of blood glucose concentration as compared to other existing approaches. Numerical as well as experimental results are also discussed to prove the validity of the proposed enhanced model for the accurate modeling of wearable sensors to be adopted for a non-invasive continuous monitoring of blood glucose in the treatment of diabetes pathology.