A Pen-Writable Electroless Plating Method for Large-Area RF Circuit Applications

This paper proposes a novel, large area, low temperature compatible approach to the fabrication of RF electronics through a combination of AM methods and electroless plating. A silver nanoparticle based ink containing particles averaging ~35 nm in size was loaded into ballpoint pens which were used to directly write 868 MHz RFID antennas upon a waterproof inkjet positive film with a microporous coating. After curing, the components were subjected to Cu electroless plating to increase conductivity, resulting in fully functional, flexible and water-resistant devices demonstrating read ranges up to 0.85 m. The effects of the Cu electroplating upon the morphology of the conductive surface and RFID antenna performance were examined. It was found that the addition of the electroless plating provided a notable enhancement to device performance without significantly impacting the advantages of high-throughput, simplicity and low cost offered by AM methods.