International audienceThis paper is mainly dedicated to the design of radio-frequency identification (RFID) tags, particularly the antennas that allow the tag to be fed, communicate, and exchange data with the reader. Good performance tags require optimized antenna that take into account numerous constraints as well as the environment of the application under consideration. Both conventional tags and robust tags are discussed. This paper also discusses how to transform a tag into an RFID sensor
International audienceThis letter proposes, for the first time, a wireless passive chipless RFID tag for identification and humidity sensing applications. The proposed sensor tag, based on time domain, consists of cascaded group of transmission-line sections (C-sections) coupled at alternative ends capable of producing group delay peaks at a particular frequency. C-sections allow producing a unique ID for a tag. Sensing is achieved by depositing silicon nanowires on the strips of the C-sections group. Silicon nanowires are very sensitive to environmental humidity variation, which in turn changes the radar cross section (RCS), phase, and group delay of the tag. This feature is utilized for humidity sensor applications. The proposed sensor tag is experimentally verified. An RCS change of 30 dB and group delay variation of nearly 22.3 ns was observed near the fundamental frequency over a bandwidth of 40 MHz for a relative humidity variation of 60.2%-88%. Measurements were performed in a real environment. The obtained results confirm the very good potential of nanowires in humidity sensor applications
International audienceA two bit planar chipless RFID tag based on group delay encoding has been presented in this paper. This chipless tag encodes data in the phase signature. The data encoding has been done by using C-sections formed by coupling the cascaded transmission line sections at alternative ends. The tag produces two different delays for two specific frequencies corresponding to the two different lengths of the transmission line sections. A measurable amount of delay has been obtained. The new approach has been validated with simulation results in frequency and temporal domain and with measurement results in frequency domain
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.