Comparison of Fabrication Techniques for Flexible UHF RFID Tag Antennas

The astonishing boom of radio-frequency identification (RFID) technology is stimulating plenty of new RFID-based industrial applications. Consequently, in the very near future, an almost unlimited number of RFID tags could be embedded into manufactured goods of various shapes, assets, and machineries to enable their communication abilities. As a result, prototyping techniques of RFID tags on flexible substrates are becoming more crucial. In this article, four different techniques suitable for prototyping flexible tags are briefly explained and tested from many points of view: Ease of use, processing time, cost, tag sensitivity, radiation pattern, impedance, and robustness of the realized prototype. Characterization methods and experimental setups are presented, and two tag layouts, one commercial and one appositely designed, are used to compare the different techniques. © 2017 IEEE

Fully 3D-Printed RFID Tags based on Printable Metallic Filament: Performance Comparison with other Fabrication Techniques

FDM (Fused Deposition Modelling) 3D printing emerged in the last few years as one of the most promising additive manufacturing techniques for fast prototyping. In this work, this technique is used to fabricate UHF (Ultra High Frequency) RFID (Radiofrequency Identification) flexible tag antennas, using a plastic-based conductive filament with copper inclusions, called Electrifi. A comparison with other prototypes with similar shape but fabricated through different and already investigated techniques [1] has been performed in terms of ease of use, processing time, cost, tag sensitivity, radiation pattern, and impedance. More specifically, 3D-printing technology for RFID tag fabrication is compared with inkjet printing, screen printing, wax-based deposition, and cutting plotter. The conductive properties of the antennas realized with the Electrifi filament, as expected, are lower than those of the antennas realized with the other techniques. Nevertheless, a slight degradation in terms of tag performances, is balanced by the extremely high versatility of the fabrication technique. Moreover, the capability to easily fabricate a fully 3D printable antenna, together with the possibility to print complex and not only planar geometries, pave the way to interesting and meaningful future developments. © 2019 IEEE

Screen Printed Flexible Radiofrequency Identification Tag for Oxygen Monitoring

In this work, a radiofrequency identification (RFID) tag with an optical indicator for the measurement of gaseous oxygen is described. It consists of an O2 sensing membrane of PtOEP together with a full electronic system for RFID communication, all printed on a flexible substrate. The membrane is excited by an LED at 385 nm wavelength and the intensity of the luminescence generated is registered by means of a digital color detector. The output data corresponding to the red coordinate of the RGB color space is directly related to the concentration of O2, and it is sent to a microcontroller. The RFID tag is designed and implemented by screen printing on a flexible substrate for the wireless transmission of the measurement to a remote reader. It can operate in both active and passive mode, obtaining the power supply from the electromagnetic waves of the RFID reader or from a small battery, respectively. This system has been fully characterized and calibrated including temperature drifts, showing a high-resolution performance that allows measurement of very low values of oxygen content. Therefore this system is perfectly suitable for its use in modified atmosphere packaging where the oxygen concentration is reduced below 2%. As the reading of the O2 concentration inside the envelope is carried out with an external RFID reader using wireless communication, there is no need for perforations for probes or wires, so the packaging remains completely closed. With the presented device, a limit of detection of 40 ppm and a resolution as low as 0.1 ppm of O2 can be reached with a low power consumption of 3.55 mA.Junta de Andalucía (Proyecto de Excelencia P10-TIC-5997 and P10-FQM-5974)Project PYR-2012-12, CEI BioTIC (CEB09-0010 and CEI2013-P-2) from CEI program of MICINNEuropean Regional Development Funds (ERDF