Top-Wall and Branch-Waveguide Hybrids for Millimeter Wavelengths (Correspondence)

Top-wall and multiple-branch waveguide couplers were developed as hybrid junctions for millimeter wavelengths, and their electrical characteristics were measured. For construction of the 55-GHz top-wall coupler, electroforming techniques were used; for the 94-GHz branch-guide coupler, the branch lines were cut directly into the wall of the main guide. Copper losses were less than 0.2 dB for the two types of couplers.