Waveguide is a special metallic channel through which radio waves are transmitted (RF is a common label for Radio Frequency signals). They provide low loss transmission and the ability to combine, filter, mix, phase shift, and otherwise manipulate the radio signals by virtue of their geometry.
Typical state-of-the-art for waveguide invovles assembly and brazement of multiple off-the-shelf parts to create complex, large assemblies. Another option is to use precision machining and EDM to get these geometries. The result is high-cost, large assemblies with a long lead time. There is a lot of precision mechanical inspection needed on each component to ensure that when you get it all together, it meets the RF requirements.
This is an ideal application for metal additive manufacturing– especially for signals below 20 GHz. However, we at QRP have had success with waveguide applications as high as 45 GHz. The application shown above was developed with Optisys and involves a labyrinth of rectangular channels encased in a protective cover. This part was designed to operate at 20 GHz and it was designed so that no support structure was needed anywhere within the interior of the channels.
The inspection of this component is more straight forward than it is for assemblies with more operation steps. In this case, you test the part for RF performance and if it meets those needs, it passes. We did RF testing on this part and found that it performed very closely to the analytical predictions and is highly functional as is.
The gains for this approach are significant. The size at least 30% of the size of competing assemblies. The weight is an order of magnitude lighter. This part took less time to design because it is a single piece and it takes less time to verify the final product because you just perform the RF testing. Finally, this part can be built and delivered in a matter of days instead of months.