Wireless Material Identification in the Recycling Chain Using Chipless RFID Tags

Abstract—The utility of chipless RFID technology for the identification of 8 materials (7 plastic types and glass) in the recycling chain is examined. We first demonstrate how the frequency response of 8 Circular Ring Resonators (CRR), designed to operate in the 1.5 - 6 GHz band, are used to encode 8 unique material IDs. Tagged items are then inserted one a time in front of a chipless RFID reader and speed and accuracy of material identification is determined. We demonstrate the ability to correctly identify material type with over 90% accuracy while being 3-16X faster than other methods reported in the literature. Techniques to further improve detection speed at the cost of accuracy are then presented. Finally, future directions of exploration are also discussed.