Fully Printable Eco-Friendly Chipless RFID Sensor

The proposed research discusses an innovative, fully passive, data-dense, and compact 15 × 15 mm² chipless radiofrequency identification tag. This tag possesses a 15-bit data, hence yielding 2¹⁵ unique ID combinations. Due to data-dense structure the tag has bit density of 6.67 bits/cm². The proposed tag is optimized and analyzed for different flexible laminates that includes Rogers (RT/duroid^®/5880), Kapton^®HN, PET, and HP-photopaper. The printability of tag is achieved by using silver nanoparticle-based conductive tracks. The conductivity of silver ink is 9 × 10⁶ S/m. The fully printable tag structure optimized with HP-photopaper substrate and silver nanoparticle-based ink hits the concept of green electronic because of organic nature of paper substrate. As paper has tendency to absorb moisture, therefore, with increasing humidity the tag behaves as humidity sensor. Due to the attractive features of the tag such as robustness, flexibility, simple printing, and need of budget friendly extensible substrates it can be located over rough places to execute sensing.