US Patent 7813145 Circuit structure with multifunction circuit cover

A cover assembly may be mounted on a substrate. The cover assembly may have an interior surface spaced from the substrate and may bound a hollow chamber over a circuit assembly. The hollow chamber may be filled with a fluid, such as a gas or a liquid. The cover assembly may also have an edge extending along the substrate around the circuit assembly and may include a dielectric cover, an electromagnetic shield, a conductive assembly, a resistive layer, and an aperture with a gas-permeable membrane. The electromagnetic shield. The dielectric cover may substantially enclose the hollow chamber bounded by the cover assembly. The electromagnetic shield may be attached to the dielectric cover and also substantially enclose the hollow chamber. The conductive assembly may extend along and may be electrically isolated from the electromagnetic shield. The conductive assembly may be conductively coupled to the circuit assembly.