Novel T-shaped resonator based chipless RFID tag

A novel, frequency selective surface (FSS) based, data encoding structure amenable to be used as a chipless RFID tag is proposed. The data encoding structure is made up of finite repetitions of a unit cell fabricated on commercially available grounded FR4 substrate having physical dimensions of 15 x 15 mm(2). The unit cell is composed of numerous T-shaped resonant elements arranged as two atypical sets of concentric nested loops. Alteration in geometry of the encoding circuit, attained by inclusion or omission of nested resonators, corresponds to a particular data sequence. Each encoded data sequence is manifested in the frequency domain as a distinct spectral signature. The proposed 10-bit tag is both compact and robust, and remains interrogable in response to illuminating electromagnetic waves at various angles of incidence.