To be a valuable global supplier
for metallic honeycombs and turbine parts
By that point, the enclosure layout is mostly fixed, and the ventilation opening ends up being added wherever space allows. This is often where airflow and shielding start to work against each other.
From an airflow perspective, the solution seems obvious. More open area means less resistance. Shorter flow paths make fans work easier. The trouble is that these same changes reduce shielding margin almost immediately.
Shielding, on the other hand, benefits from smaller openings and longer paths. Once the opening begins to behave like a waveguide, electromagnetic energy below a certain frequency is attenuated instead of passing straight through. That principle is simple enough. Making it work reliably in an enclosure is not.
Most ventilation window designs fail not because the waveguide concept is wrong, but because the balance is pushed too far in one direction. Increasing aperture size to gain a small airflow improvement can move the structure close to its shielding limit. Shortening waveguide depth to save space often removes the margin that absorbs manufacturing and assembly variation.
Airflow itself is rarely as stable as the original calculation suggests. Fan performance changes with time. Filters load up. Temperature rises shift operating points. Designs that rely on tight airflow margins often end up being modified in the field, and those modifications usually compromise shielding more than expected.
At the same time, not all shielding problems originate inside the ventilation window. Gaps around the frame, uneven clamping, or poor electrical contact can create leakage paths that bypass the waveguide structure entirely. When this happens, adjusting aperture geometry does very little to improve performance.
Surface condition inside the ventilation path adds another layer of uncertainty. Coatings, oxidation, or contamination can change attenuation near the cutoff region. These effects are subtle, but they tend to show up over time rather than during initial testing.
In practice, the ventilation windows that perform most consistently are not highly optimized designs. They use conservative geometry, leave margin on both airflow and shielding, and assume that installation and operating conditions will never be perfect.
Balancing airflow and shielding is not solved by a single calculation or parameter. It is a series of decisions made across design, manufacturing, and installation. When those decisions are made with realistic expectations, ventilation windows tend to behave as intended long after they are installed.