The effect on EMI of stitching multiple ground planes togetheralong the periphery of multi-layer PCB stacks is studied. Power busnoise induced EMI and radiation from the board edges is the majorconcern herein. The EMI at 3 meters for different via stitch spacing andlayer thickness is modeled with FDTD modeling. It is shown that theground plane stitching effectively reduces the radiated EMI that resultsfrom fringing fields at the power bus edges. Two families of curves aregenerated to demonstrate the variation of the radiated EMI as a functionof layer thickness and stitch spacing. Further studies show that thereduction of the EMI from ground plane stitching may be compromised byother radiation mechanisms
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