FR-4
FR-4 is an abbreviation for Flame Resistant 4. It is an epoxy material reinforced with a woven fiberglass mat, used in the manufacture of printed circuit boards. FR-4 is widely used to build high-end consumer and industrial electronic equipment.
| Property | Value |
| Dielectric Constant (Permittivity) | 4.60 @1 MHz |
| Dissipation Factor | 0.020 @1 MHz |
| Dielectric Strength | 500 V/mil |
Acceptable for signals up to around 10Gbs