joint plein

CONT: The waveguide comprises a thin waveguide shim having a substantially rectangular aperture or waveguide opening constructed by milling, reaming, and broaching or by electroforming or by wire electric discharge machining, or by other appropriate precision machining technique (in all cases taking care to ensure dimensional accuracy and that internal corner radii are minimized).
OBS: waveguide shim: term standardized by the International Electrotechnical Commission (IEC).