Integrated microwave circuit with non-coincident ground signal vias

摘要

An hermetically sealed integrated microwave circuit comprising a coplanar waveguide 6 on a PCB electrically connected on one major surface to an IC, and thermally and electrically connected to a BGA on its opposite major surface, in which the PCB has at least first and second printed layers 7 and 13, a microwave signal path 14 extends from a ball of the BGA (5 figure 9) through a via in both printed layers 7 and 13 to the coplanar wave guide 6, and plural ground paths extend from balls of the BGA 5 through first vias 16 in the first printed layer 7 of the PCB and through second vias 17 of the second printed layer 13 of the PCB, the first and second vias being non-coincident, to allow for an hermetic seal across the PCB whilst introducing a predetermined impedance in the PCB between the signal and ground paths.