A 920 MHz UHF RFID Tag Antenna Produced by Drop Casting Ti₃C₂T_x MXene

The continuous growth of RFID technology due to the increasing demands in healthcare and manufacturing industries has prompted the adoption and integration of novel materials in the structure of RFID identifiers. This work presents a 920 MHz UHF RFID identifier (tag) antenna, fabricated by drop-casting of MXene (Ti <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> C <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> ) on acetate substrates at ambient conditions. RFID tags with similar geometries and different thickness of MXene layers (0.4 µm and 0.85 µm) were fabricated and experimentally investigated via measuring the input impedance through scattering parameters (reflection coefficients). At 920 MHz, tags with one and two coating cycles demonstrated an impedance of Z <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> =73+j105, and Z <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> =27+j54, respectively. Drop casting and drying cycles significantly affected the input impedance of the tags, attributed to the variation of bulk conductivity in the strip-line traces. Additionally, the performance of the tags was monitored in cyclic humidity levels from 5% to 65%, which demonstrated negligible performance fluctuation of 0.48%. The initial findings suggest that drop-casting of MXene on flexible substrates has the potential to produce cost-effective and flexible RFID tags and serve as a viable substitute for conventional metallic tags.