OEVE/OENORM EN 61249-2-31
Materials for printed boards and other interconnecting structures - Part 2-31: Reinforced base materials clad and unclad for high frequency application - Halogenated modified or unmodified resin system, woven E-glass laminated sheets of defined relative permittivity (equal or less than 4,1 at 1 GHz) and flammability (vertical burning test), copper-clad (IEC 91/671/CDV)