Green Electronic Based Chipless Humidity Sensor for IoT Applications

This letter proposes a low-cost, compact, fully printable and flexible chipless radio frequency identi?cation (RFID) tag. The tag has a linearly polarized geometry and is designed within a miniaturized footprint of 20 x 10 mm^2. It has the capability to encode 15-bit data which means that it can label 2^15 number of objects. The tag demonstrates the humidity sensing feature by using HP photopaper as substrate along with silver nano-particle based conductive ink as a radiator in a frequency range of 2.4-14.6 GHz. The speciality of the tag relies in its ability to exhibit the humidity sensing phenomenon by using flexible, economical and abundantly available organic HP photopaper substrate; thus making it an excellent choice for green electronic based smart sensing applications.