Broadside Array

an antenna in the form of an array of radiators, most often balanced dipoles or slot radiators, that are excited in the same phase by high-frequency currents. The maximum radiation intensity is in the direction perpendicular to the plane of the array because the fields of all the radiators are in phase in that direction. The directional pattern of a broadside array in any plane perpendicular to the plane of the array consists of a main lobe and many side lobes with widths that depend on the linear dimensions of the array (seeANTENNA, Figure 8). In order to obtain unidirectional radiation from a broadside array, the array is supplemented with a tuned or aperiodic reflector. In cases where it is necessary to simplify the feed system of a broadside array, a unidirectional traveling-wave antenna having a small gain is used as a radiator; a director antenna, helical antenna, or log-periodic antenna may be used in such cases, obviating the need for a reflector. Broadside arrays are used for a wide range of radio waves. At decameter (short) wavelengths, they are used chiefly for radio broadcasting over long distances.