This work presents two completely printable chipless RFID tags for low-cost item labeling. The first developed tag is based on circular ring resonators where each resonator codifies a tag coding notch position. Therefore, the tag structure is scalable, printable and compact size. Moreover, a novel encoding methodology is employed to preserve the notch width and position while coding. The second developed tag is a depolarizing tag, where the polarization isolation between the reader interrogation signal and the tag response is utilized to minimize the environmental clutter reflections. Furthermore, the tag is scalable, printable and compact size within the credit card format. The proposed tags and their associated physical encoding schemes are validated using EM simulations and real-world testbed measurements. |