Overview of Coaxial Cable Design and Variations
Coaxial cables feature a dual-conductor design where two conductors are aligned as concentric cylinders with a shared central axis, separated by an insulating layer. Their broad application across diverse industries has spurred the creation of various types, each differing in material and construction.
Coaxial Cable Construction
Conductor Composition
Coaxial cables are typically made with either solid or seven-stranded conductors. Solid conductors are preferred in applications where flexibility is less of a concern, whereas stranded conductors are chosen for their higher flexibility. These conductors are often made of materials like bare copper, tin-coated, silver-plated, or nickel-plated copper. Additionally, copper-clad steel or aluminum are used, especially in high-frequency applications. Plated copper is particularly useful in contexts requiring soldering or where corrosion resistance is important.
Insulating Materials
The insulation in coaxial cables commonly employs Polyethylene (PE) or Polytetrafluoroethylene (PTFE), chosen for their reliable electrical properties. For instance:
- Polyethylene (PE): This is used in cables like RG8, RG11, RG214, RG223, RG217, RG307, and more.
- Polytetrafluoroethylene (PTFE): Found in cables such as RG142, RG142B, RG178 BU, RG179B, and others.
External Conductor
Coaxial cables typically have an outer conductor layer made up of small aluminum or copper conductors, braided around the insulation. Extra braids may be added to improve shielding.
Shielding Features
Coaxial cables sometimes include a shield, which is crucial for preserving the cable's signal integrity by protecting against electromagnetic interference.
Protective Jacket
The external jacket of coaxial cables is often fashioned from Polyvinylchloride (PVC) or Fluorinated Ethylene Polypropylene (FEP). For example:
- Polyvinylchloride (PVC): Commonly used in RG6, RG174A, RG214, RG223 cables, and others.
- Fluorinated Ethylene Polypropylene (FEP): Employed in RG142B, RG178 BU, RG179B, RG180, RG188A cables, among other RG types.
These jacketing materials not only shield the cable from environmental elements but may also add fire-retardant qualities. Regardless of the variety in their materials and build, the primary role of all coaxial cables remains consistent: to efficiently transmit signals.