For an etched EMI shield, aperture geometry and electrical continuity at the joints need to be considered together. Hole size alone cannot establish a shielding rating. Frequency, source location, enclosure geometry and assembly condition all affect the result.
Engineering guide to photo-etched EMI shielding sheets, covering materials, design, manufacturing, applications and DFM for electronics shielding components.
DFM guide to custom PCB shielding cans made by photochemical etching, covering flat-pattern design, materials, forming, plating, inspection and EMI enclosure considerations.
Guide to photochemical etching for PCB and electronic EMI shielding parts, including shielding cans, covers, frames, patterned sheets and key DFM considerations.