WAVEGUIDE FEED FOR STEERABLE BEAM ANTENNA

A steerable beam antenna includes a rotatable drum having a diffraction grating surface, and a waveguide feed including first and second conductive metal bases extending axially along the length of the drum, each of the bases having an inner surface spaced from and opposed to the inner surface of the other base, and a proximal surface spaced from the drum surface by a gap. First and second parallel conductive metal plates extend distally from the first and second bases, respectively, the first and second plates having respective inner surfaces separated by an inter-plate space. First and second dielectric strips are flush-mounted on the inner surfaces of the first and second conductive metal bases, respectively, the first dielectric strip extending longitudinally along the inner surface of the first base, and the second dielectric strip extending longitudinally along the inner surface of the second base, opposite the first dielectric strip.