Linearly polarized compact extended U-shaped chipless RFID tag

Abstract

A novel compact linearly polarized extended U-shaped chipless radio frequency identification (RFID) tag is presented. To compact the size of the tag on a single dielectric substrate, several U-shaped strips are placed on the top and several strips are placed on the bottom surface of the substrate. The top and bottom strips are connected through vias. In doing so, a smaller strip length leading to a smaller tag, on the top surface is needed for the resonance required. The proposed chipless RFID tag operates over 2–8 GHz. For an 8-bit encoded structure the substrate RO4003 has size of 7.3 × 10.2 mm2 equivalent to 0.09λg × 0.13λg. The proposed tag is simple in design, has good angular stability up to 50° and has a surface size compaction of more than 60% in comparison to the previously reported compact chipless RFID tags over a similar frequency range. An equivalent LC circuited that describes the behavior of the proposed tag is also provided. The designed chipless RFID tag is fabricated and measured. The simulated and measured results are in good agreement.