An EMI-attenuating air ventilation panel (10, 30) for an electronic device enclosure (100) in accordance with present invention includes an electronically conductive base plate (16) and a plurality of vents (12, 14, 32) defined in the base plate for forming a vents array. Each vent has extruded sidewalls (120, 140, 31) extending from sides therein. In use, the EMI from electronic components within the electronic device enclosure is efficiently attenuated by the sidewalls.