Performance of SLA and DMLS 3D Printed Ka-Band Resonators with Integrated Coaxial Launchers

A design and two different manufactured and measured components of a cavity resonator are discussed. The design process focuses on rapid prototyping in monolithic printing technologies in Direct Metal Laser Sintering (DMLS) and Stereolithography (SLA) with post-finished copper plating, and highlights the current size constraints and limitations of these two methods. The designs utilize self-supporting air-filled 3D printed rectangular coaxial lines, and a large number of release holes. These holes, also referred to as escape holes, are positioned and sized to allow for un-sintered material in DMLS to be released, while keeping spurious radiation low. For SLA devices, they aid flow of the copper and therefore more uniform plating. The unloaded quality factor (Q
0
) of the final designs in DMLS and SLA are compared, with SLA maintaining a high Q
0
of >2000. The comparative behaviours in multiple fabricated models are used to examine the manufacturing impact of copper plating, and the surface quality of copper plated SLA and current commercially available copper alloy DMLS.