In-House Fabrication of Solenoid Inductor and Multilayer Metal Core Using 3D Printing, Selective Electroless Plating, Electroplating, and Pressing

This paper presents a simple in-house fabrication of a solenoid inductor using 3D printing, selective electroless plating, and electroplating for the inductor, and pressing for a highly laminated metal core. The frame of the solenoid inductor was 3D printed, where the design of the frame has a solenoid trench and ridge for wiring and insulator, respectively. The ridge of the frame was selectively coated with a novolac resin by dipping and rolling. The unique selective electroless plating showed the direct patterning to form a solenoid conductive path that came from the different surface activation. Electroplating to thicken the solenoid wire completes the inductor fabrication. A pressing and stacking of a nickel film form the highly laminated magnetic core for the inductor. A 10-turn solenoid inductor with a wire thickness of was successfully fabricated. An average inductance of 133 nH was measured in air-core condition. A 120 nickel layer cores were integrated into the inductor and showed the boosted inductance of 252 nH. The proposed simple fabrication has a great potential for various RF passive 3D devices including antennas, filters, and waveguides.