For example, now commonly used FR-4 material, at some GHz frequency dielectric loss at the time of (dielectric loss) on signal attenuation has a great impact, may not be combined.

• 例如，现在常用的FR-4材质，在几个GHz的频率时的介质损(dielectric loss)会对信号衰减有很大的影响，可能就不合用。