Sectoral hoghorn: a new form of line feed for spherical reflector aerials

A sectoral hoghorn may be used as a line feed to correct spherical aberration in an offset spherical reflector. The bandwidth of this type of feed is considerably greater than that of other line feeds, and the construction is simple. The results of measurements on a prototype X band hoghorn are reported, and a technique for reducing the area of spherical reflector required for a given scan angle is described.