SLA-Printed 3-D Waveguide Paths for E-Band Using Electroless Silver Plating

Abstract

This paper proposes a fabrication approach for 3-D printed waveguide paths based on a combination of an optimized electroless silver plating process with a waveguide-specific design rule for general metal plating by introducing large-scale non-radiating slots into the broad and narrow waveguide walls with a periodicity shorter than a quarter of the guided wavelength. Experimental fabrication of straight sections of the proposed slotted waveguide with various gap dimensions yields an optimum gap size as a result of a tradeoff between silver plating quality and leakage losses through the sidewall gaps. Moreover, a successful practical application of the proposed approach is presented in terms of a 3-D printed multiple bend waveguide interconnect in three different space dimensions, which imposes a complex task for conventional manufacturing techniques due to the need of multiple cutting planes for split block assembly. The proposed approach has the benefits of low cost, moderate handling effort, and independence of the concrete geometry to manufacture, making it, therefore, especially interesting for distribution and feeding networks in the context of rapid prototyping, automotive, and space-related applications.