How much does a gap in a data center switch chassis affect RE shielding?

Gaps in data center switch chassis are the main path for radiation leakage. A gap length > λ/20 (λ/20 = 50mm at 300MHz) constitutes an equivalent slot antenna. Actual measurements showed that reducing the screw spacing on the chassis cover from 50mm to 25mm reduced the average radiated field strength from 30MHz to 1GHz by 8-12dB. Adding conductive foam or springs to reduce the gap impedance to <10mΩ further reduced radiation at 500MHz by 6dB. Design requirements: screw spacing ≤ λ/20 (≤ 15mm based on the highest operating frequency of 1GHz); conductive oxidation treatment at joint surfaces, contact resistance < 2.5mΩ; ventilation holes using waveguide window honeycomb structure with a aperture < 3mm. Actual measurements showed that after optimization, the overall radiation margin is > 6dB, meeting Class A standards.