Waveguide directional coupler with multiple coupled outputs

A directional coupler apparatus, comprising:

• an elongated rectangular first waveguide including first and second conductive broad walls spaced apart by third and fourth conductive narrow walls, all centered on a longitudinal axis;
• a thin, elongated conductive septum, said septum extending from said first to said second narrow walls, for dividing energy propagating in said first waveguide into at least first and second signal portions flowing in first and second channels, respectively, said septum being elongated generally in the direction of said axis and extending from a first transverse plane transverse to said axis to a second transverse plane transverse to said axis within said first waveguide;
• an elongated rectangular second waveguide including first and second conductive broad walls spaced apart by third and fourth conductive narrow walls;
• an elongated rectangular third waveguide including first and second conductive broad walls spaced apart by third and fourth conductive narrow walls;
• first directional coupling aperture means opening into said first broad wall of said first waveguide at locations between said first and second transverse planes, and also opening into said second broad wall of said second waveguide for coupling first signal subportions of said first signal portions between said second waveguide and said first channel of said first waveguide with a first selected coupling factor;
• second directional coupling aperture means opening into said second broad wall of said first waveguide at locations lying between said first and second transverse planes, and also opening into said first broad wall of said third waveguide for coupling second signal subportions of said second signal portions between said third waveguide and said second channel of said first waveguide with a second selected coupling factor,
• whereby a signal entering said first waveguide near said first transverse plane is divided into said first and second signal portions, flowing in said first and second channels of said first waveguide, respectively, and said first and second coupling aperture means directionally couple said first and second signal subportions, respectively, to said second and third waveguides respectively, with said first and second coupling factors, respectively, and the remaining energy of said first and second signal portions recombines at said second transverse plane of said first waveguide.