RIDGE SCAN ANTENNA

An elongated horizontally disposed waveguide has a series of holes in one longitudinal side wall dimensioned below cut-off so as to be non-resonant and insensitive to wave length variations. The dimensioning and spacing of the holes on the one longitudinal side wall provides for radiation of a fan shaped beam in a vertical plane having a fairly broad elevational angle and an extremely narrow azimuth angle. The fan shaped beam itself is caused to scan through a given angle in azimuth by means of a ridge member reciprocated wholly within a new waveguide structure T shaped in cross section. In addition to the unique waveguide shape and hole design for coupling energy from the waveguide, novel input and output transition structures are provided. The waveguide is typically used in the leading edge of an aircraft wing as a radar antenna.