Abstract

A waveguide to microstrip transition (124) formed in a multi-layer substrate (208) is disclosed. The waveguide to microstrip transition (124) may be incorporated into a hermetically sealed package including a metal base (202), a multi-layer circuit (208), a metal ring (206), and a metal cover (204). The multi-layer circuit (208) has at least a first dielectric layer (230), a second dielectric layer (222), and a first conductive layer (218) disposed between the bottom side of the first dielectric layer (230) and the top side of the second dielectric layer (222). The multi-layer circuit (208) includes a waveguide (234). An electromagnetically reflective material (236) coats the walls of the waveguide (234) to allow signals to propagate by reflection through the waveguide (234) toward the first dielectric layer (230). Plated through vias (126) are located in at least the first dielectric layer (230). The plated through vias (126) are arranged to form an approximate outline around the land region on the first dielectric layer (230). The plated through vias (126) form a waveguide extension to the waveguide (234) that guides signals through the first dielectric layer. A microstrip (112) is located on the top side of the first dielectric layer (230). The microstrip (112) connects to an E-plane probe (113) located over the waveguide (234) and inside the waveguide extension.