Analysis of the use of different substrates for the design of C-sectioned folded microstrip chipless tag for pressure detection

Chipless RFID tags in different flexible substrates with folded multi-layer C-sections intended for wireless pressure sensor are presented in this paper. These folded tags use of dispersive characteristics of C-sections in order to build structures with greater group delay dependent on the physical characteristics of the C-section. This increased group delay is a result of a more intense electromagnetic coupling due to the folding process on the tag. It has been discovered, using simulation on CST Microwave Studio, that the air within each layer of the tag destroys partially the electromagnetic coupling and that expelling this air applying pressure over the tag rebuilds it; hence it is possible the devise an instrument capable of detecting pressure using this concept. This work tested different substrates used to design these tags; and, it suggests that changing the substrate of the tag affects positively, depending on the type of the substrate used, the group delay and also can contribute to achieve economic constraints. In synthesis, this work implies, with its obtained results, the viability of the utilization of tags with multi-layer C-sections in temporal multi-frequency encoding technique based on group delay for pressure detection.