Air Gap Corrections in Clamped Stripline in Plane Permittivity Extraction
Air gap corrections eliminate systematic two to six percent dielectric underestimation in clamped stripline tests, preventing finished board impedance failures.
Ceramic Filled Thermoset
Composite Formulation
Polymeric materials engineered with inorganic micro-particles provide the high thermal stability and low electrical loss required for demanding high-frequency printed circuit board substrates. A ceramic filled thermoset combines a polymer matrix with ceramic fillers to achieve a low coefficient of thermal expansion and highly stable electrical properties. This combination resists the softening and flow that typically occurs in unfilled polymers during soldering and assembly.
Material Performance
The integration of ceramic particles increases the density of the compound and reduces its rate of dimensional change under thermal stress. This stability prevents microvia cracking and minimizes delamination between the copper foil and the dielectric during lead-free assembly cycles. It also helps to maintain a consistent dielectric constant across a wide range of temperatures.
Fabrication Characteristic
Substrates utilizing this composite matrix are generally harder to drill, which increases drill bit wear and requires carefully optimized feed rates during mechanical fabrication. This hardness is compensated for by the excellent dimensional stability and reliability the material provides in harsh environments. Consequently, the material is frequently selected for aerospace and defense electronics where thermal endurance is a primary engineering requirement.
The uniform distribution of the ceramic phase also prevents localized variations in trace impedance, providing highly predictable signal propagation times for microwave circuitry.