Design and experimental characterization of on-skin loop antenna for next 5G backscattering-based communications

Backscattering-based communications are promising solutions for large scale body-centric monitoring systems, for the low power requirements and the simple and lightweight electronics. Currently, UHF frequency band represents the golden standard, mainly thanks to the well assessed Radio Frequency IDentification (RFID) technology. However, early studies proposed the exploitation to the upcoming 5G communication infrastructures to overcome the limitations in bit-rate and bandwidth and the need of a dedicated reading platform to interact with the tags. The aim of the work is to experimentally verify, from the antenna perspective, the possibility to adopt the 5G 3.6 GHz frequency band also for the next generation body-centric backscattering systems. An epidermal loop antenna is hence designed and prototyped. Measurements in real conditions, e.g., on the human body and through a custom testbed emulating a real backscattering link, are presented as well as statistical analysis on human variability. Results over five volunteers confirm the possibility to read the epidermal tag up to 1.2 m, hence enabling monitoring within a medium-size room.