Upper-bound Performances of RFID Epidermal Sensor Networks at 5G Frequencies

5G will play a key role in developing high speed wearable and epidermal electronics for healthcare applications such as patient monitoring, tele-surgery, and augmented sensorial abilities (both for humans and robots). At the same time, developing a 5G-RFID system based on backscattering communication will help reducing the power consumption and lowering the electronic complexity. Nevertheless, the high path losses and the strong electromagnetic interactions of the skin might severely limit ranges and performances of epidermal RFIDs operating at 5G frequencies. In this paper, the effects of the human skin on the link budget of epidermal RFID dipoles at microwave and mmWave frequencies are investigated through numerical simulations. Results show that an epidermal RFID sensor tags can reach ranges comparable with UHF systems by using either a single dipole at 5.8 GHz or a 23-element array of dipoles at 60 GHz when using the currently available chip sensitivities (-15 dBm) and reader antenna gains (6 dBi). Smaller antenna sizes of a 5G RFID sensor will allow the integration of tags in new ubiquitous non-invasive epidermal and wearable electronics, while the high frequencies will enable tracking with mm- and micro-scale resolutions for medical applications (e.g.: micro-ablation or muscular and neural rehabilitation).