A Coaxial cable is a type of cable that is used to make transfer RF/Microwave signals. These cables usually consists of an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield and an outer covering. Over time properties of standard coaxial type cables have been standardized. Standardization makes the selection of cables much easier as now you do not need to depend on any single manufacturer for cables, you can get cables for a particular standard from different manufacturers - through the electrical properties might vary slightly based on the quality and production procedures of a manufacturer.
| Properties of Coaxial Cable Dielectrics
(c = speed of light in a vacuum) | ||
| Dielectric Type | Time Delay (ns/ft) | Propagation Velocity |
|---|---|---|
| Solid Polyethylene (PE) | 1.54 | 0.659c |
| Foam Polyethylene (FE) | 1.27 | 0.800c |
| Foam Polystyrene (FS) | 1.12 | 0.910c |
| Air Space Polyethylene (ASP) | 1.15-1.21 | 0.840c-0.880c |
| Solid Teflon (ST) | 1.46 | 0.694c |
| Air Space Teflon (AST) | 1.13-1.20 | 0.850c-0.900c |