Impact of Shorting Vias Placement on Embedded Planar Electromagnetic BandGap Structures Within Multilayer Printed Circuit Boards

This paper investigates the power integrity behavior of planar electromagnetic bandgap (EBG) structures embedded between two solid layers within the stack-up of a multilayer printed circuit board. The bandgap generation and power integrity performance of the embedded EBG can be achieved only by placing vias shorting the solid planes above and below the patterned layer. The vias inhibit the resonances of the cavity made by the two solid planes, ensuring the designed bandgap, as if the planar EBG was laid out on an outer stack-up layer. The impact of the stitching vias´ number and location is addressed and the concepts of regular, global, random, or local via placement are introduced.