Group delay modulation for pulse position coding based on periodically coupled C-sections

Chipless radio frequency identification (RFID) is an emerging research area nowadays. The recent development in this area proves its efficiency to compete with low cost identification systems like barcodes in the upcoming years. Chipless RFID encodes data using different kinds of spectral signature produced from some planar images as in the case of barcodes, the difference here is those images are made with conductive materials. Among the different ways of information encoding, a powerful way of encoding is time domain approach. This paper incorporates a tag using group delay encoding. The proposed chipless tag is composed of commensurate cascaded transmission line sections coupled at alternative ends (also known as C-sections). It consists of single group of C-sections. However, in order to increase the coding capacity, the proposed tag can allow multi-frequencies also. In addition to this, the tag is also compatible with commercial ultra wide band radar. The proposed tag is validated experimentally. It exhibits a good reading range of 1.2 m.