Coaxial to waveguide adapter. Manufactured model needs metal plating before use. SMA connector dimensions for Amphenol SV Microwave SF2950-6061. EM-simulations for copper version give matching <-15dB (WR112-WR62). Waveguide surface roughness seems a bit too high for a waveguide. Possible workaround ABS and acetone? Needs measurements to verify performance. Otherwise just nice decoration.