Horn antenna is an antenna used for transmission and reception of signals at microwave frequencies. There are several configurations; most have a square or rectangular cross section. The antenna provides a unidirectional radiation and response pattern, with the favored direction coincident with the opening of the horn. The feed line consists of a waveguide that joins the antenna at the narrowest point (throat) of the horn. This type of device is used alone in microwave transmitters known as Gunnplexers. The device works well in the feed systems of large dish antennas; the horn is pointed toward the center of the dish, in the opposite direction from the favored direction of the dish.
See also DISH ANTENNA, GUNNPLEXER.