lobe
From Glossary of Meteorology
In an antenna pattern, a region of local maximum in the emitted intensity. The strongest lobe is in the pointing direction of a directional antenna and is called the main lobe.
The configuration of lobes is determined by three factors: 1) wavelength; 2) geometrical properties of the antenna and feed system; and 3) mutual interference between the direct and reflected rays for an antenna situated above a reflecting surface. The sidelobes or minor lobes are an unavoidable consequence of the finite size of the antenna. Though undesirable, they ordinarily contain much less power than the main lobe.
See antenna pattern.