Coaxial Cable

Anatomy of Coaxial Cable

Posted on Wednesday, February 3, 2016 by Paige DiAntonio

As defined by Merriam-Webster, coaxial cable is a transition line that consists of a tube of electrically conducting material surrounding a central conductor held in place by insulators and that is used to transmit telegraph, telephone, and television signals.  They are most well-known for applications such as broadband Ethernet, home-video equipment, commercial radio, and closed-circuit television. Coaxial cable is capable of protecting television and other signal systems from interference, providing high quality picture, and static prevention.

Coaxial cable construction includes 4 parts:

  1. Inner conductor
  2. Outer conductor, typically a shield (an optional second shield can be present as well)
  3. Dielectric material to separate the inner and outer conductors
  4. Jacket

Below are 5 of the most common types of coaxial cable.

Triaxial Cable (Triax): Triax has two outer conductors separated by a dielectric layer. One outer conductor serves as a signal ground, and the second serves as earth ground. Having two outer conductors provides better noise immunity and shielding.

Flexible Coax: This is the most common type of coaxial cable. Flexible coax has a braided outer conductor, allowing the cable to be flexible but does not provide complete shielding. In order to provide better coverage, may coax cables have several layers in the outer conductor and thin foils may be used to enhance shield effectiveness.

Semi-rigid Coax: Similar to the shape of a pipe, Semi-rigid Coax has a solid, tubular outer conductor. This construction lacks flexibility but gives the cable uniform characteristic impedance.

Dual Coax: Cable containing two individual coaxial cable surrounded by one common jacket.

Twinaxial (Twinax): Unlike the original construction of coaxial cable, Twinax encompasses a twisted or parallel pair of conductors rather than just a single inner conductor.


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