Manufacturing technologies for UHF RFID epidermal antennas

Skin-mounted electronics is the next wave beyond wearable devices for unobtrusively picking up vital signs (temperature, hydration, biopotentials...) over the body surface. The recent evolution of UHF RFID technology towards epidermal sensing applications plays a key role to provide stick on sensors with wireless powering and remote reading. In this paper different state of the art manufacturing technologies (carved adhesive copper, microwires, inkjet printing with self-sintering Ag-ink and photolithography) are applied to the fabrication a small size UHF RFID epidermal sensor suitable for measurements of the surface body temperature. Performance of the resulting prototypes are systematically compared in terms of achievable maximum gain, usability of bio-compatible conformable substrates, time and costs for large-scale production.