Fabrication of a Flexible RFID Antenna by Using the Novel Environmentally Friendly Additive Process

Abstract

The fabrication of flexible antennas for RFID applications can be divided into subtractive and additive methods. In this study, a low-cost additive method is proposed, which involves printing aluminum paste and utilizing a galvanic replacement reaction. Through a galvanic replacement process, copper sulfate waste effluent was employed to convert the aluminum electrode into a highly conductive copper electrode. The physical characteristics of the Cu electrode, such as surface flatness, thickness, and Al-Cu conversion ratio, were studied. The Cu electrode, produced using an innovative additive technique at a temperature of 75°C for 15 minutes, exhibits the lowest resistivity of 5.89 × 10–8 Ωm. This resistivity is comparable to that of a commercial silver thick film electrode, making it suitable for use in manufacturing RFID antennas for RFID module applications. With an S11 of −40 dB at 1.26 GHz, a maximum gain of 2.87 dBi, a maximum efficiency of 53.63%, and a reading distance of 9 meters, the RFID module demonstrates impressive performance. The reading distance of an RFID module with a copper foil antenna is longer (8.5 meters).