Specialized Filament
Advanced fiberglass yarns with a low dielectric constant improve the speed and clarity of signals in high performance electronics. The low-dk l-glass uses a different chemical composition than standard e-glass to reduce the amount of energy absorbed by the board material. This material is typically found in servers, network switches and high speed computing applications.
Permittivity Reduction
Specialized designs select these glass fibers to minimize the delay and distortion of digital signals as they travel through the board. A low-dk l-glass provides a more consistent electrical environment because its properties are closer to those of the epoxy resin. This compatibility reduces the signal skew that occurs when a trace passes over the alternating regions of glass and resin in the weave.
The lower permittivity also allows for thinner dielectrics without increasing the risk of electrical loss.
Signal Propagation
Using these fibers increases the overall cost of the board but provides the headroom needed for future data rates. The low-dk l-glass is often paired with high performance resins to create a laminate that works at frequencies where standard materials fail. Fabricators must handle these materials carefully during the drilling and plating stages because the glass can have different mechanical properties than the common alternatives.
