Radio frequency circuit board with microstrip-to-waveguide transition

A method of fabricating a radio frequency (RF) printed circuit board (PCB), comprising:

• disposing a patch antenna element on a first dielectric layer, the patch antenna element including a slot aperture;
• disposing a microstrip transmission line on a second dielectric layer;
• disposing a ground plane on a third dielectric layer;
• laminating, sequentially, at least the first dielectric layer, the second dielectric layer, and the third dielectric layer into a board assembly such that the microstrip transmission line is configured to be electromagnetically coupled to the ground plane and electromagnetically coupled to the patch antenna element through the slot aperture;
• disposing a dielectric lens on the patch antenna element;
• and
• attaching an aperture of a waveguide to a top surface of the first dielectric layer and enclosing the patch antenna element such that the dielectric lens extends into the aperture of the waveguide, the waveguide configured to be electromagnetically coupled to the patch antenna element through the dielectric lens.