Do the ventilation holes on data center switches reduce the effectiveness of RE shielding?

Improperly designed ventilation holes in data center switch chassis can severely reduce shielding effectiveness. Circular hole arrays have 8-12 dB lower leakage than elongated slotted holes. Theoretically, a slotted antenna is formed when the maximum linear dimension of the hole slot is greater than λ/20. At 1 GHz, λ/20 = 15 mm, so the diameter of the ventilation holes should be ≤3 mm or a waveguide window honeycomb structure (depth-to-diameter ratio ≥4:1) should be used. Actual measurements show that a 5 mm diameter circular hole array (10 mm spacing) has only 8 dB shielding effectiveness at 800 MHz; switching to a 3 mm circular hole array improves the shielding effectiveness to 22 dB; adding a conductive mesh ventilation plate can restore 28 dB. During design, prioritize openings on the sides and rear panel of the chassis, avoiding front openings directly facing the CPU/switch chip.