Frequency Shift Coded Chipless RFID Tag Design using Square Split Ring Resonators

Radio Frequency Identification (RFID) is an automatic tagging and tracking technology, that uses Radio Frequency (RF) electromagnetic waves for non-line-of-sight communication. This paper presents a chipless RFID tag, designed using square Split Ring Resonators (SRR). The ID of the tag is encoded into spectral domain and the RFID tag's coding capacity has been increased from 4-bit to 8-bit by using Frequency Shift Coding (FSC) technique. The substrate used for the tag design is FR4 substrate which has the relative permittivity (e-) of 4.3 and dielectric loss tangent (tan (i) of 0.02. The tag works in the frequency band ranging from 1.43 GHz to 4.01 GHz. The working of the tag is ensured by observing surface current distributions of the tag at resonant frequencies.