CADFEKO supports two methods to specify the size of
the apertures for a braided shield layer.
The optical coverage for a braid indicates how visible the apertures
are, where 0% is completely open (no shielding) and 100% is a completely filled
(approximating a solid shield). The optical coverage and weave angle are coupled by the
fill factor (F) for a braid, which is a quantity between 0 and 1.
Figure 1. Illustration of the braid parameters for a braided shield layer.
The fill factor (F) is calculated from the optical coverage using the following
equation:
(1)
where the optical coverage is between 0% and 100%.
The coupled equation for the fill factor from the braid parameters is:
(2)
where D is the mean braid diameter (outer radius of the
shield minus half the thickness of the braided layer).
Optical Coverage
For the optical coverage definition, a minimum optical coverage is specified. The
minimum optical coverage relates to the largest aperture size or minimum shielding
that CADFEKO tries to achieve when optimising the
braid for maximum coverage, by varying the weave angle.
Weave Angle
A nominal weave angle and deviation is specified for the weave
angle definition. The optical coverage is calculated for the range of weave angles
to represent the size of the apertures (using the braid parameters defined for a
braided layer).
Note: As the weave angle changes, the shield diameter also changes
depending on the weave angle and other braid parameters.
