UCR: An Unclonable Environmentally Sensitive Chipless RFID Tag For Protecting Supply Chain

Chipless Radio Frequency Identification (RFID) tags that do not include an integrated circuit (IC) in the transponder are more appropriate for supply-chain management of low-cost commodities and have been gaining extensive attention due to their relatively lower price. However, existing chipless RFID tags consume considerable tag area and manufacturing time/cost because of complex fabrication process (e.g., requiring removing or shorting some resonators on the tag substrate to encode data). Worse still, their identifiers (IDs) are deterministic, clonable, and small in terms of bitwidth. To address these shortcomings and help preserve the cold chain for commodities (e.g., vaccines, pharmaceuticals, etc.) sensitive to temperature, we develop a novel unclonable environmentally sensitive chipless RFID (UCR) tag that intrinsically generates a unique ID from both manufacturing variations and ambient temperature variation. A UCR tag consists of two parts: (i) a certain number of concentric ring slot resonators integrated on a certain laminate (e.g., TACONIC TLX-0), whose resonance frequencies rely on geometric parameters of slot resonators and dielectric constant of substrate material that are sensitive to manufacturing variations, and (ii) a stand-alone circular ring slot resonator integrated on a particular substrate (e.g., grease) that will be melted at a high temperature, whose resonance frequency relies on geometric parameters of slot resonator, dielectric constant of substrate material, and ambient temperature. UCR tags have the capability to track commodities and their temperatures in the supply chain. The area of UCR tag is comparable to regular quick response (QR) code. Experimental results based on UCR tag prototypes have verified their uniqueness and reliability.