Derivation of Rectangular Metallic Waveguide Attenuation Constant for IEC 60153-2 and IEEE 1785.1 International Standards

The IEC 60153-2 and IEEE 1785.1 international standards for rectangular metallic waveguides are currently undergoing revision. Textbook derivations of the associated equations for the metal-pipe rectangular waveguide attenuation constant to be given in the revised standards are presented. These derivations provide important mathematical traceability for these equations, which has previously not been proven in the open literature for these standards. Furthermore, the historical approximations used in the original equations are identified and now corrected here. Results using the newly derived equations are demonstrated, with comparison to experimental results in the WM-380 (500 GHz to 750 GHz) band.