| 摘要 |
<p>An improved foam dielectric coaxial cable in which the foam dielectric composition comprises a foamed melt extrudable fluorinated ethylene-propylene (FEP) polymer containing therein a PTFE nucleating agent and blown to a foamed structure by means of a volatile fluid -- e.g., a lower fluorocarbon such as fluoromethane or, preferably, fluoroethane. The foam dielectric is characterized by its thermal stability, file resistance, small closed cell structure, low density, and low insulating loss characteristics. In a preferred embodiment, the foam dielectric has cells ranging from 10 to 40 mils., a density at least as low as 1.0 g. cc., and an insulation loss of less than 1.8 db/100 ft. at 1000 MHz.</p> |
