This standard gives specifications for the waveguide (including aperture dimensions@ frequency range@ cut-off frequency@ etc.). This standard considers the tolerances of the waveguide aperture dimensions and the effect these have on the electrical properties (in terms of return loss@ transmission loss@ etc.) of the waveguide. Purpose The purpose of this standard is to provide the agreed reference for all organizations using rectangular waveguides at these frequencies. This will enable efficient trade between customers and suppliers@ and common design criteria and practices for component@ systems@ and design engineers.