3-D Printed Waveguide Filters: Manufacturing Process and Surface Mounted Assembly

Abstract

This article presents a new approach to manufacturing and assembling inexpensive, lightweight devices using 3-D-printed waveguides, and surface-mount technology (SMT). Specifically, we have employed stereolithography (SLA) and a combination of electroless and electroplating processes to develop cavity filters in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C$ </tex-math></inline-formula> -bands. The filters can be efficiently integrated into planar circuits via a reliable and simple transition that enables surface-mount assembly. Two resonator topologies, circular and rectangular, were examined and compared to develop <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula> -band filters, and a triplet topology has been developed for the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C$ </tex-math></inline-formula> -band. The measured frequency responses were consistent with simulations, with insertion losses below 2 and 1.43 dB for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C$ </tex-math></inline-formula> -bands, respectively. We have conducted several Monte Carlo analyses and a dimensional study to assess the impact of manufacturing tolerances on filter performance. Furthermore, a rectangular cavity resonator has been used to approximate the effective conductivity of the deposited copper coating, considering the detrimental effects of oxidation and surface roughness. The resulting effective conductivity of 17.7 MS/m was found to be higher than the current state-of-the-art values. Finally, SMT assembly offers several advantages over traditional methods, including reduced size, simplified assembly, and integration with planar systems. The results presented in this work indicate that combining 3-D printing and SMT provides a simple and efficient solution for developing lightweight and highly integrated components with superior performance.

Topics & Concepts