Ambient sensing by chemical-loaded UHF-RFIDs

A planar double-patch folded structure is proposed to achieve a miniaturized, highly sensitive and tunable UHF RFID passive sensor tag. The geometry hosts a radiating slotline which can host Chemical Interactive Materials (CIM) able to detect the relative humidity level or the presence of different gases in air. The resulting antenna surface is half the size of a credit card, ensures good communication performance (up to 10m read range), and high sensitivity to the agent under test. The estimated low cost, the light weight and the small size make this passive sensor suitable for pervasive and large scale applications in the quality assessment of the air.