Substrate-free Epidermal Tattoo Antennas for NFC and UHF Applications

Epidermal electronics, including tattoo antennas, represent a promising solution for wireless biomedical applications, providing ultra-thin, skin-conformal devices that integrate seamlessly with the human body. However, traditional designs rely on polymeric substrates that, while providing mechanical support, can limit flexibility, breathability, and long-term wear-ability. In this work, we investigate the use of gold nanomesh conductors for substrate-free epidermal tattoo antennas for Near Field Communication (NFC) and Ultra-High Frequency (UHF) RFID antennas. Numerical simulations were performed to evaluate the impact of sheet resistance, conductor thickness, and antenna geometry on overall performance. Results demonstrate that sub-skin depth conductors can provide acceptable efficiency, with NFC coils requiring multiple thin layers to meet resonance conditions, while UHF antennas show moderate performance degradation compared to traditional conductors. These findings highlight the potential of gold nanomeshes as a candidate material for epidermal tattoo antennas, paving the way for experimental validation.