Practical RF Handbook, 4th Edition

Appendix 5

RF cables

Coaxial cables

These consist of an inner conductor surrounded by insulation, which in turn is surrounded by a metal sheath. The metal sheath may be solid copper (sometimes, especially in cables with a high power rating, this is corrugated), copper braid or tape (sometimes both), and covered with an outer insulating sheath, which may incorporate armouring. The inner conductor is usually copper, sometimes silver plated, or silver plated steel. The inner insulation may solid, or for a low loss cable, a foamed cellular material, e.g. polythene. For the lowest loss cables the inner insulation may consist of a filament of insulating material wound round the inner - with very few turns per centimetre, or the inner may be supported ...