Prototyping flexible UHF RFID tags through rapid and effective unconventional techniques: Validation on label-type sensor-tag

As a matter of fact, electromagnetic labs involved in label-type UHF RFID tags design, realize their tag prototypes making use of either very rudimentary methods, by shaping the tag antenna on a copper film through a handy cutter, or photolithography methods based on rigid PCB, which give out non-flexible devices. In this work two innovative prototyping techniques suitable for built-in-lab flexible tags are presented. The former method is mainly based on the use of a cutting plotter to precisely shape the tag antenna on adhesive copper tapes. The latter makes jointly use of flexible PCBs and solid ink printers. Once introduced and discussed, the new prototyping methods have been electromagnetically characterized and results have been compared with the canonical photolithography. At the end of the paper, the very challenging test-case of the practical realization of a flexible Sensor-Tag is presented. The measured and shown performance confirms the appropriateness of the proposed prototyping techniques even for complex RFID-based structures.