S. Manzari

Polymer-doped UHF RFID tag for wireless-sensing of humidity

Passive UHF RFID tags, beside item labelling, are also able to exploit capability of sensing the physical state of the tagged object as well as of the surrounding environment. Here a family of polymer-doped tags are proposed and fully characterized for the detection of ambient humidity. A sensitive chemical species based on PEDOT:PSS is used to dope a properly shaped slot carved into a folded-like patch tag. The communication and sensing capabilities of the radio-sensor are investigated by means of simulation and measurements showing how to control and balance above opposite requirements by dosing the quantity of sensitive material. The device could have interesting application in the assessment of the air quality in living and controlled rooms, in the monitoring of the conservation state of foods, in the preservation of walls, and even to monitor the healing degree of wounds.

Miniaturized and tunable wearable RFID tag for body-centric applications

A planar “square-smile” like layout is proposed to achieve miniaturized wearable UHF RFID tags. The geometry hosts different slots which contribute to produce size reduction and a two-steps friendly impedance tuning. The resulting antenna surface is half the size of a credit card and permits to be read up to 5m when attached onto the body. Thanks to the flexible and lightweight EPDM foam used as substrate, the tag is suited to be integrated in badges, wallets, pockets, plasters, wristbands and various garments. The particular slotted geometry moreover simplifies the interconnection of chemical or mechanical sensors. An example is given concerning a passive motion detector for the live tracking of human movements and pathological/vital signs in a conventional room.

Development of an UHF RFID Chemical Sensor Array for Battery-Less Ambient Sensing

Battery-less ultrahigh frequency (UHF) radio frequency identification (RFID) tags coated by proper sensitive layers have been recently demonstrated capable to play as low-cost sensors of some volatile compounds. The issue of cross-sensitivity and the possibility to develop an array of differently coated sensors are, however, still completely open. This paper investigates, through an experimental campaign involving a general-purpose sensor-antenna transducer, the potentiality of functionalized tags in the UHF RFID band to sense a multiplicity of volatile compounds, as well as the cross-sensitivity effects of different coatings in array configuration. Four effective materials, such as Pedot:PSS, doped PSS, SWCNT, and PDAC, revealed a remarkable sensitivity to ammonia, ethanol, octane, and water. Wireless sensing may be hence performed by narrowband processing of the power response of the RFID tags as well as by the broadband extraction of features related to the resonance shift. It was finally observed how the inter-antenna coupling may affect the sensor capability of an array of UHF tags in term of increased cross-sensitivity.

Feasibility of wireless temperature sensing by passive UHF-RFID tags in ground satellite test beds

Satellite ground testing is nowadays suffering from long and complicated measurement procedures, where cabled sensors are involved: as such, it could strongly benefit from wireless sensing capabilities, enabling simplified measurement setup procedures and substantial cost reduction. Passive RFID wireless sensors are improving in maturity and robustness for Earth use and could be optimal candidates also for Space-related applications. The present work shows a first attempt to evaluate the performance of newly developed temperature-monitoring RFID sensor tags for satellite ground testing, both from a sensor point of view and from a EMC/EMI perspective.

Phase-oriented chemical sensing by passive UHF-RFID

Most of up to day efforts to extract physical information from an object where an RFID tag is attached on are based on the processing of the backscattered power reflected by the tag and collected by the reader. This contribute investigates, for the first time, the use of the phase of the reflected field to derive quantitative information about chemical variations of the environment, nearby the tag. The proposed methodology is described throughout a controlled laboratory experiment involving a chemical doped RFID tag for humidity sensing.

Multi-channel processing of RFID backscattering for monitoring of overnight living

Movement detection of human body is a fertile research field in human-computer interaction, as well as in medical and entertainment applications. Moving limbs within an electromagnetic field radiated by an interrogating antenna will generate a modulation of the backscattered field detected by a receiver. The measured signals may therefore carry raw information about the human motion and behavior. Moreover, the proper placement of UHF passive Radiofrequency Identification (RFID) tags over body segments will increase the amount of collected signals. This paper investigates the possibility to detect the quality and phenomenology of the sleep by processing the multichannel power data coming from a set of wearable passive radio-sensors placed onto the sleepers clothes as well as over the bed and onto the nearby carpets. The resulting ambient-intelligence system is characterized by numerical electromagnetic models as well as by extensive experimentations.

Body-centric RFID systems

Recent progresses in the design of wearable RFID tag antennas stimulate the idea of passive body centric systems wherein the required power to drive the wearable tags is directly scavenged from the interrogation signal emitted by the reader unit. While active body-centric links have been extensively investigated, the feasibility of passive systems is still questionable due to the poor sensitivity of the tags and to the modest read distances. This paper describes an articulated measurement campaign with textile wearable low-profile tags in the UHF RFID band. It is demonstrated that both on-body and off-body links are feasible with a power budget fully compliant with the available technology. The experiments permits to identify the most efficient tag placements and to propose some quantitative and general guidelines useful to characterize and design this kind of new systems.

RFID sensing breadboard for industrial IoT

A fully reconfigurable RFID Sensing breadboard for Industrial Internet of Things is here proposed. The board is completely tunable such to offer the best communication performances in different industrial operative scenario. Furthermore, thanks to the customizable expansion traces and the A/D frontend, the radio-board is capable to interface up to two external sensors and to work in both passive and BAP mode.

Experimental characterization of bodycentric passive RFID systems

Recent progresses in the design of wearable RFID tag antennas stimulate the idea of passive bodycentric systems wherein the required power to drive the wearable tags is directly scavenged from the interrogation signal emitted by the reader unit. While active bodycentric links have been extensively investigated, the feasibility of passive systems is still questionable due to the poor sensitivity of the tags and to the modest read distances. This paper describes an articulated measurement campaign with textile wearable low-profile tags in the UHF RFID band. It is demonstrated that both on-body and off-body links are feasible with a power budget fully compliant with the available technology. The experiments permits to identify the most efficient tag placements and to propose some quantitative and general guidelines useful to characterize and design this kind of new systems.