Abstract: A broadband turnstile waveguide junction has four rectangular side ports that lie in a common plane, symmetrically about and orthogonal to a longitudinal axis of a circular port. The turnstile waveguide junction comprises a circular to quad-ridged waveguide transition disposed between the circular port and the four rectangular side ports. Quad-ridged waveguide ridges are provided that transition to a single ridged waveguide in the four rectangular side ports. A transition is provided from the single ridged waveguide to rectangular waveguide in the side ports. A center matching post, or pedestal, extends from the rear of the junction a predetermined distance toward the circular port. Another embodiment may use a quad-ridged waveguide having a port at the input in lieu of a circular to quad-ridged transition. Another embodiment may use single ridged waveguides at each side port instead of transitioning from single ridged waveguide to rectangular waveguide.

Abstract: A broadband turnstile waveguide junction has four rectangular side ports that lie in a common plane, symmetrically about and orthogonal to a longitudinal axis of a circular port. The turnstile waveguide junction comprises a circular to quad-ridged waveguide transition disposed between the circular port and the four rectangular side ports. Quad-ridged waveguide ridges are provided that transition to a single ridged waveguide in the four rectangular side ports. A transition is provided from the single ridged waveguide to rectangular waveguide in the side ports. A center matching post, or pedestal, extends from the rear of the junction a predetermined distance toward the circular port. Another embodiment may use a quad-ridged waveguide having a port at the input in lieu of a circular to quad-ridged transition. Another embodiment may use single ridged waveguides at each side port instead of transitioning from single ridged waveguide to rectangular waveguide.

Abstract: An antenna for providing a broadband omnidirectional circumferential radion pattern is formed by an array of arcuate waveguide radiators arranged to form a cylindrical antenna. Each waveguide radiator has a ridged waveguide cavity and a plurality of longitudinally-oriented slots communicating with the waveguide cavity. The slots are arranged in two parallel rows on either side of the longitudinal centerline in a staggered relationship along the outside surface of the radiator. Each radiator is fed from the interior of the cylindrical array at a feed point located at the center of the radiator.