Inkjet-printed meta-material inspired passive antenna sensor for UHF RFID systems

A fully passive low-cost wireless UHF RFID antenna based sensor for Internet of Things applications is presented. The proposed sensor consists of a closely spaced two-element dipole antenna with a printed sensor electrically connected to one of the antennas. A metamaterial-inspired resonator is used to improve isolation between the two antennas and optimize the size of the antenna structure. The radiating and sensing structure is inkjet-printed on photo-paper using a silver nanoparticle ink, and commercial RFID chips are connected to each of the two antenna terminals. The tag dimensions are 84mm × 89mm and the tag is compatible with an EPC Class 1 Gen 2 (UHF) standard reader operating at 915 MHz. The design methodoly of the sensor as well as theoretical analysis and experimental results are presented.