Passive UHF RFID antennas for sensing applications: Principles, methods, and classifcations

Abstract

Abstract-UHF passive Radio Frequency Identification technology is rapidly evolving from simple labeling to wireless pervasive sensing. A remarkable number of scientific papers demonstrate that objects could be in principle remotely tracked and monitored in their physical properties all along their daylife. The key background is a new paradigm of antenna design that merges together the conventional communication issues with more specific requirements about sensitivity to time-varying boundary conditions. This paper proposes a unified introdution to the tag-as-sensor problem with particular care to formalize the measurement indicators and the communication and sensing trade-off, with the purpose to understand and classify the state of the art and definitley provide a knowledge base to face a large variety of emerging applications.

Switchable disposable passive RFID vapour sensors from inkjet printed electronic components integrated with PDMS as a stimulus responsive material

“…A number of good overviews and reviews of RFID chemical sensors are available in the literature. 2,3,17 In contrast we propose a disposable passive RFID sensor system in the UHF band for a long read range, typically several metres, which is sensitive to a broad range of vapours utilizing a stimuli-responsive polymer substrate but where the stimuliresponse is mechanical. This is similar in principle to the sensor mechanism as described by Fiddes and Yan 16 but rather than measuring small differences in conductivity, the system we describe behaves as an on-off switch where electrical conductivity in an antenna component is essentially stopped by a mechanical response from the substrate.…”

Chipless RFID Tag Exploiting Multifrequency Delta-Phase Quantization Encoding

“…T RACKING of goods, people localization, remote identification, and access control are only some of the multiple applications in which radio frequency identification (RFID) has been exploited in the recent years [1], [2]. Commercialized RFID tags are mainly passive and consist of an antenna connected to a chip.…”

Wireless Crack Monitoring by Stationary Phase Measurements from Coupled RFID Tags

“…It would be instead beneficial to have wireless, low-cost and passive sensors able to remotely provide the information about the state of the crack in a structure at a given time. Among the many possible technological options, sensors based on radiofrequency identification (RFID) [3] appear to be promising thanks to the maturity of commercial off-the-shelf (COTS) components, the virtually infinite lifetime of passive transponders and the overall low cost that would enable a widespread distribution over large areas, that is instead prevented by the high cost of active devices. The recent attempts to use RFIDs to record and monitor the evolution of cracks in civil or mechanical structures may be categorized into two main families concerning deforming antennas and two-parts sensors.…”

“…The present paper introduces instead a completely different approach, since it exploits the phase of the backscattered signal as carrier of the sensing information, while minimizing the degradation of communication performance by means of an ad-hoc design procedure. Working with phase turns out to be attractive, especially if using a COTS reader to collect measurements, thanks to: i) the large dynamic range of phase measurements (between 0 and 180 ); ii) the possibility, as shown later on, to overcome or at least mitigate, the degradation of the communication performances typical of amplitude-oriented sensing method (see [3] and [11] for a detailed review). The phase change is achieved by letting the crack's displacement modify the electromagnetic coupling among two facing tags under couplet-mode radiation.…”