The effect of standing waves on the attenuation constant for a low‐loss rectangular waveguide

When standing waves are present in a rectangular waveguide, the resistive losses in the walls are not uniformly distributed. This affects the measurement of the attenuation constant. Here the phenomenon for the TE10 mode in air‐filled waveguide, where the deviation from the normal travelling wave attenuation constant is only about ±1% over the conventional bandwidth, is discussed. However, the paper also shows that nearer the cut‐off frequency for the waveguide, the deviation could be as high as ±100%.