Waveguide adapter plate to facilitate accurate alignment of sectioned waveguide channel in microwave antenna assembly

A method of fabricating an antenna apparatus, the method comprising:

• fabricating a waveguide adapter plate comprising:
• a metal plate comprising:
• a first surface and an opposing second surface;
• a waveguide flange interface comprising:
• a first waveguide channel section extending between the first surface and the second surface;
• and
• a first set of flange mounting holes extending from the first surface to the second surface;
• and
• a slot extending from an edge of the metal plate to a location proximate to a perimeter of the first waveguide channel section and extending from the first surface to the second surface;
• and
• a plurality of substrate alignment pins extending substantially perpendicular from the second surface;
• mounting an integrated circuit (IC) package at the second surface of the waveguide adapter plate, the IC package having a third surface facing the second surface and an opposing fourth surface, the IC package further comprising:
• a set of alignment holes compatable with the plurality of substrate alignment pins;
• a second set of flange mounting holes extending from the third surface to the fourth surface and compatible with the first set of flange mounting holes;
• a first metal layer proximate to the third surface, the first metal layer comprising a launcher element and a first ground plane coplanar to the launcher element;
• a second metal layer proximate to the fourth surface, the second metal layer comprising a second ground plane;
• a waveguide channel aperture comprising a first region surrounding the launcher element, the first region being substantially devoid of conductive material;
• and
• a via fence comprising metal vias disposed at a perimeter of the first region and extending from the first ground plane to the second ground plane;
• and
• wherein the waveguide channel aperture is aligned with the first waveguide channel section;
• providing an antenna flange having a fifth surface and an opposing sixth surface, the antenna flange further comprising:
• a second waveguide channel section extending from the fifth surface;
• and
• a third set of flange mounting holes extending from the fifth surface to the sixth surface and compatible with the first and second sets of flange mounting holes;
• and
• providing an antenna subassembly by mounting the antenna flange to the waveguide adapter plate and the IC package using a first set of bolts so that the fifth surface faces the first surface, wherein each bolt extends from the fourth surface to the sixth surface via corresponding flange mounting holes in each of the first, second, and third sets of flange mounting holes.