Integrated Honeycomb Shielding Fan for EMI applications
Publication Date: 2010-May-13
The IP.com Prior Art Database
Integrated honeycomb shielding fan for EMI applications is described.
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For some applications, it is essential to provide higher levels of shielding effectiveness to contain electromagnetic emissions. One of the weaker points in the packaging design involves an EMC and thermal trade-off at the air mover. The fan needs to move large amounts of cooling air for system requirements. The following figures and discussion describes a hardened fan structure for better shielding effectiveness (see Figure 1).
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High shielding and high percent open can be established with honeycomb between the overlapping blades. Although resistance will be increased, the angle of the honeycomb is optimized to pass air flow. The size of the honeycomb aperture as well as its length establishes the shielding effectiveness obtained. The honeycomb placed between the blades allows the fan to maintain a height profile lower than that possible with just honeycomb placed over the entire fan (see Figure 2).
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The simplified view in Figure 3 below does not show the final angle of the honeycomb optimized for efficient air flow. The honeycomb length would be rotated about the center hub as well as angled parallel to the blades.
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Shown below in Figure 4 is the honeycomb placed between overlapping blades of a 5-blade fan (shown without the hub).
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The bands and rings along the outside edge of the fan blades to maintain an RF tight enclosure is...