A component of the beam of an individual antenna, or of the synthesized beam of an antenna array, away from the main response, representing an unwanted response to radiation from a direction in which the antenna or array would ideally be insensitive
A local maximum off the center peak on a graph of antenna gain in dBi against the angle from the center of the reflector The graph is three dimensional, and theoretically symmetrical in two dimensions, about the center of the reflector Large sidelobes for Earth Stations cause interference with Satellites adjacent to the receiving Satellite
Part of an antenna's radiation pattern which can detect or radiate signals in an unwanted direction (i e off-axis), which can produce interference into other systems or susceptibility to interference from other systems The larger the side lobes, the more noise and interference an antenna can detect Sidelobe levels are determined by the design of the antenna