coma lobe

coma lobe

[′kō·mə ‚lōb]
(electromagnetism)
Side lobe that occurs in the radiation pattern of a microwave antenna when the reflector alone is tilted back and forth to sweep the beam through space because the feed is no longer always at the center of the reflector; used to eliminate the need for a rotary joint in the feed waveguide.
References in periodicals archive ?
Coma produces a large first sidelobe, the coma lobe, which quickly grows to within a few dB of the gain peak.
95 for a comparably sized paraboloid, gain at 30 [degrees] falls by more than 2 dB, and the coma lobe is as high as 7 dB down from peak gain.