Quasi-Optical Transmission Loss Extraction for High-Frequency Stackup Design
Quasi-optical extraction isolates intrinsic substrate loss from copper roughness, requiring explicit z-axis anisotropy conversion for accurate mmWave stackup design.
Woven Glass Reinforcement
Mechanical Skeleton
Structural substrate component provides the mechanical strength and dimensional stability required for rigid printed circuit boards. Woven glass reinforcement consists of bundles of fine glass filaments interlaced at right angles to form a fabric. This fabric is impregnated with resin to create prepreg or core materials.
The density and thickness of the weave determine the mechanical and electrical properties of the resulting laminate.
Resistance to Expansion
Stability against thermal expansion and mechanical warping depends on the orientation of the glass fibers within the resin matrix. Woven glass reinforcement constrains the resin as it heats up, preventing excessive movement in the X and Y axes. This stability is critical during the high temperature cycles of lead-free soldering.
Without this reinforcement, the board would lack the rigidity needed to support heavy components.
Dielectric Uniformity
Variations in the distribution of glass and resin across the surface of the board can lead to localized changes in the dielectric constant. Because woven glass reinforcement has a higher permittivity than the epoxy resin, signals passing over a glass bundle travel slower than those passing over a resin-rich area. This effect, known as the fiber weave effect, can cause timing jitter and signal skew in high speed digital circuits.
Manufacturers address this by using spread-glass fabrics or non-woven alternatives for the most sensitive applications.