Epidermal Radioelectronics: The Next Frontier of Wearable Systems

Epidermal or Skin Radioelectronics, is a currently emerging research trend combining multi-disciplinary expertises such as Material Science, Mechanics, Electronics and Electromagnetics. Recent worldwide published papers demonstrated the feasibility of thin and flexible systems over thin and bio-compatible conformable membranes for direct placement over the human body. The direct on-skin collection of physiologic parameters may enable in a very near future a fan of new applications to consumer electronics, personal human health and wellness. In this scenario, the virtuous synergy of Epidermal Radio-Electronics with the latest research trends in RFID and low-cost inkjet printing could boost the applicability of skin technology in the real world, providing a further facilitator of the rapidly emerging Internet of Things. However, the cohabitation of passive antenna elements with the human skin represents an intrinsic challenge because of the high losses of tissues that strongly degrade the radiation efficiency. Unlike wearable antennas that are decoupled from the body by means of spacers or ground planes, the radiating elements of epidermal devices must act as both sensor and antenna and therefore must be placed in direct contact with the body. The epidermal tag has moreover to be designed in order not to interfere with the local metabolism of the skin. Accordingly, the substrate is required to be not only bio-compatible but also breathable. This talk will offer a personal perspective over bio-integrated epidermal radio-sensors, based on the latest research upon the Pervasive Electromagnetics Lab of the University of Roma Tor Vergata. Starting from a theoretical discussion on the upper-bound communication performance of on-the skin antennas, materials and different fabrication techniques, several sensing systems will be presented involving the live temperature measurements and its preliminary clinical trial, the detection of breath by means of graphene sensors, up to RFID-based Finger Augmented Devices (FAD) for the restoration of lost touch senses in impaired people.