>>10307792No, because it is not dispersing through a volume but it is following the waveguide in a path. The energy is dissapated as it is absorbed by the waveguide. It also loses coherence as it travels down the waveguide for other reasons.
Microwaves don't use waveguides, the interior is metal and the front grating is too small for the large wavelength to travel through. So the EM waves just bounce around inside because metal reflects microwaves.
