A novel EM barcode for humidity sensing

In this paper, a novel low cost, compact, printable EM barcode or chipless RFID tag is presented for humidity sensing. The RFID tag sensor is based on planar, single sided resonant scatters operating within the frequency band of 6.5 GHz to 9.5 GHz. Within this frequency range a rectangular patch with a number of slot resonators is designed to designate the data ID. In addition, an electric inductive-capacitive (ELC) resonator is dedicated for humidity sensing. The ELC resonator is modified using polyvinyl- alcohol (PVA) to incorporate humidity sensing. Moreover, the tag sensor can be printed on flexible laminates like plastic and paper for ultra-low cost item level tagging and ubiquitous sensing. The sensor tag has potential of including multiple parameter sensing as the sensing mechanism is independent of data ID generation. It has remarkable application in low cost perishable product process and management.