Design of Implanted RFID Tags for Passive Sensing of Human Body: The STENTag

Abstract

Abstract-Numerical processing of passive UHF-RFID tags' response may provide physical insight about the hosting object or about the nearby environment. This idea is here extended to implanted antennas with the purpose to sense the evolution of some human physiological and pathological process involving a local change of effective permittivity inside the body. The goal is to understand how master the design of this class of devices taking into account both communication and sensing capabilities. An ad hoc design methodology is here presented and discussed by means of a realistic medical case concerning the modification of an endo-vascular device to achieve a STENTag able to sense the state of the vessel wherein it has been implanted.Index Terms-Biosensor, implantable biomedical device, passive sensing, RFID.

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

“…Their application is less effective in Europe due to the very modest allowed bandwidth. [18]; c) Analog identifier measured at different observation angles [12]; d) Integral metrics: scale factor [19]; e) Integral metrics: frequency shift [20] f) Binary detection of temperature threshold [21] As for usual sensors, the response of the S-tag can be quantified by the dynamic range, e.g. the overall change of the measured parameters between the extreme interesting realizations of the process, Ψ min , Ψ max , conveniently expressed in decibel (10) and by means of the Sensitivity…”

“…Hence the true effectiveness of an S-tag results from the trade-off between sensing and communication [19]. Sensing requirements induce a constraint over the dynamic range:…”

“…Examples of Effective-permittivity S-tags. a) Low-permittivity filling level sensor [15]; b) High-permittivity filling level sensor [27]; c) Highpermittivity discrete filling level sensor [28]; d) Concrete water infiltration sensor [29]; Biological process sensors: e) the STENTag [19], f) Cerebral Edema monitoring [30].…”

“…By adding the RFID IC, it is possible to transform the cardiovascular device into a radio-sensor able to monitor the restenosis process which induces a change in the properties of the tissues surrounding the tag [19].…”

Next generation RFID telemetry design for biomedical implants.

“…Since then, the use of RFID has become pervasive in modern society. Radio Frequency Identification is widely used today in diverse applications such as inventory control, theft prevention, road toll collection, animal identification and recently as implantable medical devices [25].…”