Design of Microwave Components using Direct Metal Laser Sintering

Additive Manufacturing holds significant promise for microwave component design, enabling the production of previously un-manufacturable, complex designs through 3D printing. The research here reports the modelling, simulation, fabrication and testing of several microwave components, including the world’s first ever 3D metal printed Sierpinski gasket antenna, with multiple resonance characteristics. One concern of 3D metal printing relates to surface finish. The impact of inherent surface roughness on the performance of the printed antenna has also been evaluated. Further, two different surface treatment techniques have been used and the RF improvement has been assessed. Considering the fact that these treatments may not be available to the wider RF community, two other possible ways to limit the surface roughness have also been highlighted and tested. 3D printing, being a layer-by-layer process, enables the designing of self-supportive structures through topological design optimization. This property has been utilized to design self-supportive, non-solid interior microwave components, to reduce their weight. The results showed the weight of the metal printed inner lattice antenna to be even lighter than a similar metal-coated (solid) polymer antenna, fabricated with comparatively similar RF performance. In another exploitation, an alternative approach to mounting an antenna to its feeding circuitry has been developed, by printing an intricate, N-type female feed together with the microwave component, as a single monolithic component. A final development related to enhancing the performance of existing antennas, including the fabrication of a novel horn antenna, with in-built periodic structures positioned at bespoke positions for side-lobe reduction and the first ever attempt at 3D printing an artificial dielectric lens, for possible 5G and power applicator applications.