I am trying to figure out Ku-band antenna consisting
a prime focus parabolic reflector à sub-reflector-->circular
outer corrugated waveguide à omt. It is backfire
feed so that feed assembly ( OMT) is located behind
of reflector. I am having a hard time to understand
what is function of outer corrugation of waveguide.
The corrugation looks like rings.
has any clue of the function of outer corrugation
of waveguide ?