Flared trough waveguide antenna

Abstract

A flared trough waveguide antenna capable of being used at high microwave and millimeter wave frequencies is disclosed herein. The antenna includes a conductive trough having first and second ends, a bottom surface, and first and second opposing side surfaces electrically coupled to the bottom surface. A conductive fin is electrically coupled to the bottom surface between the first and second opposing side surfaces. The bottom surface includes a first planar portion between the conductive fin and the first side surface, and a second planar portion between the conductive fin and the second side surface. The conductive trough may be induced to radiate electromagnetic energy by introducing an offset between the first and second planar portions with respect to the plane of the conductive fin. The antenna further includes first and second flared surfaces, respectively coupled to the first and second side surfaces, for directing electromagnetic energy radiated by the flared trough waveguide antenna. The first and second flared surfaces each optionally define a plurality of corrugations for attenuating sidelobes of the radiated electromagnetic beam pattern. A planar array may be realized by placing a plurality of flared trough waveguide antennas adjacent each other. Each antenna within the array includes first and second planar bottom portions arranged asymmetrically relative to the vertical plane of a conductive fin therebetween. Electromagnetic energy is coupled into one end of each of the antennas within the array by way of a feed system.