Design, simulation, and fabrication of low-cost chipless rfid tags

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2019
Çetin, Elif
In this thesis, low-cost chipless radio-frequency-identification (RFID) tags are investigated. These types of tags are proposed and developed to replace barcodes in item-level tagging. In addition to the standard methods using printed circuit boards (PCBs), chipless RFID tags are suitable to be fabricated via low-cost inkjet printing. In these low-cost fabrications, tags are printed on photopapers via commercial inkjet printers loaded with silver-based inks. Various tag designs are simulated via the multilevel fast multipole algorithm (MLFMA) and their radar-cross-section (RCS) values are rigorously studied to developed superior designs for high performance identifications. This study particularly focuses on frequency-based chipless RFID tag designs, where data is encoded via resonators. Existences of the resonators induce resonance peaks at the backscattered RCS response of the tag such that the data is encoded in binary notation depending on the resonators’ absence or presence. In other words, tags having different ID words generate different signatures in the RCS spectrum. To construct an RFID system, RCS responses are collected in an ID library, while the tags that yield poor RCS responses are removed from the library based on an elimination rule. In addition to the conventional tags, novel array strategies are investigated to increase the reliability and readability of the tags at the cost of reduced compactness. Furthermore, novel hourglass structures, which have more compact forms and enhanced RCS performances in comparison to the standard structures, are investigated. Finally, fabricated tags are tested in anechoic chamber by using various calibration techniques. While satisfactory results are obtained with PCB-based tags, improvements are needed to construct RFID systems involving inkjet-printed tags.
Citation Formats
E. Çetin, “Design, simulation, and fabrication of low-cost chipless rfid tags,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Electrical and Electronics Engineering., Middle East Technical University, 2019.