A novel Interconnected Patch-Ring (IPR) structure for noise isolation

Electromagnetic bandgap (EBG) structures are currently the most effective means to suppress noise coupling in microelectronic packages and boards. Since EBGs are periodic structures, they require periodically arranged patches, vias and in some cases, surface mount capacitors and inductors, to suppress noise within a desired frequency range. However, all these components take up much of the board/package space and very little space is left for the placement and routing of the ldquoactualrdquo components needed for system functionality. EBGs therefore, reduce the integration density of electronic packages and boards. Furthermore, due to the periodicity of the patches, transmission lines referenced to the patterned layer(s) of EBGs suffer from return-path discontinuity (RPD) problems, which severely degrade their electrical performance. In this work, we quantify some of the electromagnetic reliability (EMR) problems caused by EBGs. We then propose a novel planar noise isolation structure, the interconnected patch-ring (IPR) structure, which is just as effective as EBGs in noise isolation, but overcomes some of the limitations of EBGs.