A graph of the sensitivity or gain of a radio telescope in various directions. A typical antenna pattern shows several sensitivity maxima (lobes) of which the strongest (the main lobe or main beam) defines the direction in which the telescope is most sensitive. An antenna pattern with a narrow main lobe of circular cross-section and negligible side lobes is known as a pencil beam, while a pattern with a wide, flat main lobe is known as fan beam. See also Polar Diagram.
Subjects: Astronomy and Astrophysics.