Low cost chipless tag with multi-bit encoding technique

A novel compact chipless RFID tag with multiple bit encoding using Stepped Impedance Resonator (SIR) is proposed. Unique code of the tag is encrypted in the frequency spectrum by incorporating variations in magnitude of the scattered field. Fundamental mode and first harmonics of the SIR is effectively utilized to represent the data. Two bit information can be represented by one SIR, therefore the tag is capable to represent 2^2N number of bit combinations with N resonators. A prototype of the tag is fabricated on a substrate of dielectric constant 4.4 and loss tangent 0.0018. Working model of SIR tag with 2 bit representation is demonstrated in this paper.