Development of Enhanced Range, High Q, Passive, Chipless RFID Tags for Continuous Monitoring and Sensing Applications

A high Q planar chipless RFID tag with high sensitivity is proposed for communication applications. In particular, the tag structure is composed of a complementary spiral structure (CSS) that is able to provide high sensitivity and compactness. A semi analytical formula for the design of a single bit tag is derived, and the behaviour of the CSS is analysed for different dielectric substrates. Different tags, composed of up to a set of eight resonators, have been numerically and experimentally assessed. In particular, a system prototype composed of a reader and a set of tags are fabricated and experimentally assessed as a proof of concept. The system provided an operative range of tens of centimetres (a maximum operative range of 65 cm). The obtained results are quite promising and the agreement between simulated and measured results are found to be good.