UCR: An unclonable chipless RFID tag

While Radio Frequency Identification (RFID) has become popular for commodity and asset tracking and management, the relatively higher price of RFID tags limits its application in the supply chain of low-cost commodities. Recently, cost-effective chipless RFID tags that do not contain a microchip in the transponder have been gaining more attention from industry, academia, and government. Existing chipless RFID tags require removing or shorting of some resonators (i.e., spirals or patch slots) on the substrate to encode data, but this incurs a waste of tag area and increases the manufacturing time/cost of chipless RFID tags. In addition, the identifiers (IDs) generated by existing chipless RFID tags are small, deterministic, and clonable. To mitigate these shortcomings, we propose a new unclonable chipless RFID (UCR) tag that intrinsically generates a unique ID from manufacturing variations. UCR tag consists of a certain number of concentric ring slot resonators, whose resonance frequencies depend on slot parameters and substrate dielectric constant that are sensitive to manufacturing variations. The area of UCR tag is as small as regular quick response (QR) code. Simulation results based on CST Microwave Studio 2015 have verified the effectiveness and reliability of UCR tags. The non-overlapping margin between intra-tag and inter-tag Euclidian distance distributions reaches approximately 50 MHz in the presence of random white Gaussian noise (WGN) with a signal-to-noise ratio (SNR) of 10 dB.