A Fully Inkjet-Printed 3-D Honeycomb-Inspired Patch Antenna

The ability to inkjet print three-dimensional objects with integrated conductive metal provides many opportunities for fabrication of radio frequency electronics and electronics in general. Both a plastic material and silver conductor are deposited by inkjet printing in this work. This is the first demonstration of a fully 3-D multijet printing process with integrated polymer and metal. A 2.4-GHz patch antenna is successfully fabricated with good performance proving the viability of the process. The inkjet-printed plastic surface is very smooth, with less than 100 nm root mean square roughness. The printed silver nanoparticles are laser sintered to achieve adequate conductivity of 1e6 S/m while keeping the process below 80°C and avoiding damage to the polymer. The antenna is designed with a honeycomb substrate that minimizes material consumption. This reduces the weight, dielectric constant, and dielectric loss, which are all around beneficial. The antenna is entirely inkjet-printed including the ground plane conductor and achieves an impressive 81% efficiency. The honeycomb substrate weighs 20 times less than a solid substrate. For comparison, the honeycomb antenna provides an efficiency nearly 15% greater than a similarly fabricated antenna with a solid substrate.