Issue link: https://resources.pcb.cadence.com/i/1541046
22. Building Ground Via Fences and Edge Stitching Ground via fences (closely spaced rows of ground vias along PCB edges, can shield perimeters or block noisy boundaries) help contain electromagnetic fields, suppress edge radiation, and provide robust return paths for high-frequency currents. Without dense via stitching, copper pours or shield cans are less effective, and fringing fields can escape at board edges, connectors, or slots, causing EMI failures. Via fences are a key technique for meeting EMC standards and ensuring consistent high-frequency behavior. When And Where To Apply Apply ground via fences wherever strong shielding is needed: around board edges, RF modules, high-speed blocks, shield can outlines, sensitive analog regions, and along critical power or signal partitions. Especially critical in designs subject to FCC, CE, CISPR, automotive, or medical EMC requirements. A simplified cross-section shows a via passing through multiple plane layers at the PCB edge, with all planes stitched to ground. Placing ground vias around the perimeter at λ/8 spacing forms a via fence, creating a short boundary that reflects high-frequency noise back to the source.