Radar assembly with ultra wide band waveguide to substrate integrated waveguide transition

1. An assembly comprising:

a rectangular-waveguide (RWG) that propagates electromagnetic energy in a transverse electric mode TE 10 and in a first direction; and

a printed-circuit-board that includes a plurality of conductor-layers oriented parallel to each other, said printed-circuit-board defines a substrate-integrated-waveguide (SIW) that propagates electromagnetic energy in a transverse electric mode TE 10 and in a second direction perpendicular to the first direction, and defines a transition that propagates the electromagnetic energy between the rectangular-wave-guide and the substrate-integrated-waveguide, wherein the transition includes apertures defined by at least three of the plurality of conductor-layers.

2. The assembly in accordance with claim 1 , wherein a first layer of the plurality of conductor-layers is adjacent the rectangular-waveguide, said first layer defines a first aperture characterized by a first-size, and a last layer of the plurality of conductor-layers is adjacent to the substrate-integrated-waveguide and defines a horizontal-boundary of the substrate-integrated-waveguide, said last layer defines a last aperture characterized by a last-size greater than the first-size.

3. The assembly in accordance with claim 2 , wherein an intermediate layer of the plurality of conductor-layers is located between the first layer and the last layer of the transition, said intermediate layer defines an intermediate aperture characterized by an intermediate-size between the last-size and the first-size.

4. The assembly in accordance with claim 1 , wherein the transition includes a short-wall that defines a vertical-boundary of the transition.