Design and Development of Sensing RFID Tags on Flexible Foil Compatible With EPC Gen 2

Fully Printed Flexible Single-Chip RFID Tag with Light Detection Capabilities

“…The antenna impedance must be a complex conjugate of the chip impedance to maximize the power transfer between the antenna and the chip [20]. The RFID chip input impedance was taken from our previous work [11] and its value is (31 − j286) Ω. A dipole antenna resonating at the European UHF RFID band defines the radiofrequency interface.…”

“…Finally, as a matching network, one RF Surface Mount Device (SMD) inductor in series on one of the dipole arms was needed to provide the necessary large inductive part [20]. This SMD inductor could be avoided by changing the antenna layout (i.e., bow-tie antenna [11]), but we decided to include it in order to reduced area and materials. The tag has been designed to occupy a total area of 5 × 5 cm 2 .…”

“…Different techniques can be used to fabricate RFID tags with PE, from screen-printing to inkjet printing or gravure; furthermore, the tag can be fabricated directly on the desired substrate, such as paper or plastic substrate. Not only the antenna and the connections can be manufactured by PE [11,12], but also the sensor capabilities can be developed with these techniques [13,14,15]. Many sensors useful for packaging monitoring have been already developed [16].…”

Printed single-chip UHF passive radio frequency identification tags with sensing capability

“…The only element more expensive is the selected chip but its price is in the order of other UHF chips. Regarding SMD components, RF inductor could be avoided including the matching network in antenna's layout as presented by Salmerón et al [20]. In this particular solution, a reference capacitor is required, so this element could not be avoided but its cost is insignificant compared to the cost of the RFID chip.…”

“…In this regard, several RFID tags with sensing capabilities, sometimes referred as to smart RFID tags, have been already developed following different strategies [20]. Some authors have associated a change in the analogue response of the sensing RFID tag, such as read range or shift of the antenna resonance frequency, to the variation of the monitored magnitude [4,19,[21][22][23][24][25][26][27][28][29][30].…”