A biocompatible and flexible polyimide for wireless sensors

This paper presents a flexible antenna fabricated on a biocompatible polyimide parylin thin layer and operating in the radio-frequency identification at ultra high frequency band (RFID UHF: 860-960 MHz). An original RFID UHF tag exhibiting high performance using biocompatible materials is presented in this study. The tag antenna was first simulated in electromagnetic analysis to optimize performance and dimensions. 3D electromagnetic simulations are presented and the intended antenna performance is validated experimentally. The antenna was successfully tested in an anechoic chamber. The manufacturing processes and validation measurements are detailed. The material and fabrication techniques reported here could be extended to achieve other types of stretchable sensors based on polyimide thin layers or other biocompatible materials, for biomedical and RFID applications. Our experimental results suggest that this biocompatible thin layer is suitable for manufacturing flexible and stretchable antennas, which can potentially be used for identifying wearable items and food packaging. A future goal is miniaturization to enable applications involving implants inside the human body.