9.3: Fabrication of solid copper 220 GHz folded waveguide circuits by UV lithography

We report the fabrication results for an all-copper 220 GHz folded waveguide circuit. The fabrication method is based on UV lithography using SU-8 negative photoresist followed by copper electroforming. The method achieved the necessary dimensional accuracy, smooth vertical side walls, low cost of fabrication, and all-copper structure suitable for high power applications.