Microelectronic package with antenna waveguide

A method of forming a microelectronic package, comprising:

• forming a waveguide radiation receiver in a first conductor layer on a first surface of a multilayer package substrate;
• forming a second conductor layer on a second surface of the multilayer package substrate spaced from the first conductor layer by a dielectric layer;
• forming a transmitter-receiver on the second surface of the multilayer package substrate;
• forming a feed line coupling the waveguide radiation receiver to the transmitter-receiver, the feed line including a conductive via traversing the dielectric layer coupling a first portion of the feed line in the first conductor layer to a second portion of the feed line in the second conductor layer;
• and
• mounting a tubular waveguide to the multilayer package substrate such that a central aperture of the tubular waveguide is over the waveguide radiation receiver, wherein mounting the tubular waveguide to the multilayer package substrate includes soldering the tubular waveguide to the first conductor layer at a ground plane around a profile of the central aperture.