Base Material
Insulating structural foundations in electronic assemblies support the conductive copper traces that connect components. Choosing a suitable pcb substrate requires evaluating both mechanical strength and electrical isolation properties at the operating frequency of the circuit. Glass-reinforced epoxy and ceramic materials are common choices for these boards.
Dielectric Constant
Signal propagation speed and impedance control are directly affected by the electrical permittivity of the board material. The choice of pcb substrate dictates the spacing and width of high-speed transmission lines to ensure signal integrity. This constant must remain stable across the intended temperature and humidity range.
Mechanical Support
Rigidity and dimensional stability are needed to prevent solder joint cracking during thermal expansion and contraction. A low thermal expansion coefficient of the pcb substrate prevents delamination and trace breakage during high-temperature reflow soldering. This physical integrity is verified through standard deflection and peel strength testing.
Thermal Conductivity
Dissipating heat from high-power active components to the ambient environment requires high thermal performance from the core layers. Metal-clad or ceramic-based pcb substrate options are used when standard epoxy cannot meet the heat dissipation requirements. This selection ensures that the junction temperature of critical components remains within safe operating limits.
