Embedded wireless strain sensors based on printed RFID tag

Purpose - The purpose of this paper is to develop a wireless strain sensor for measuring large strains. The sensor is based on passive ultra high-frequency radio frequency identification (RFID) technology and it can be embedded into a variety of structures.Design methodology approach - Silver ink conductors and RFID tags were printed by the screen printing method on stretchable polyvinyl chloride and fabric substrates. The development of the strain-sensitive RFID tag was based on the behavior of the selected antenna and substrate materials. Performance of the tags and the effect of mechanical strain on tag functioning were examined.Findings - The results showed that large displacements can be successfully measured wirelessly using a stretchable RFID tag as a strain-sensitive structure. The behavior of the tag can be modified by selection of the material.Research limitations implications - New tag designs, which are more sensitive to small levels of strain and which have a linear response will be the subject for future work. Tag performance under cyclic loading and in a real environment will also be investigated. Future work relating the investigation of practical applications and the system designing for the strain sensor will also be required.Practical implications - Printing is fast and simple manufacturing process which does not produce much waste or material loss. The sensor is a new application of printed electronics. It also provides new opportunities for system designers.Originality value - The paper provides a new kind of wireless strain sensor which can be integrated into many structures (i.e. clothes). The sensor is a new application of printed electronics and it is made from novel materials.