Finger-Augmented RFID system to restore peripheral thermal feeling

Finger-Augmented Devices (FAD) identify a particular wearable technology suitable to turn the human fingers into enhanced sensing surfaces for advanced human-computer interfaces. The feasibility of a full on-body UHF RFID-based FAD is here investigated for the first time. The system is aimed at providing impaired people suffering from a lack of thermal feeling, due to pathological disorders, with a realtime feedback of the temperature sensed by the fingertips. The considered RFID-FAD comprises an epidermal tag suitable to conformal application over the fingertip and an interrogation wrist patch antenna. The electromagnetic challenge concerns the possibility to establish a robust RFID link when both the reader antenna and the passive fingertip tag are attached onto the lossy human skin. The occurring near-field interaction is modeled by a two-port system and experimentally tested by means of a 3D hand mockup made by additive manufacturing. Simulations and measurement permitted to derive the upper-bound performance and to estimate the required power budget. The idea is finally demonstrated with a proof of concept in a realistic application.