There are two concentric coaxial cable is a conductor, and conductor and a shield but also share the same axis of the cable. The most common coaxial cable isolated by the insulating material composed of copper conductor, insulation material in the inner layer is a layer of circular external conductor and an insulator, then the cable is made from PVC or Teflon wrap jacket material. Currently, there are two types of coaxial cable used: 50Ω and 75Ω coaxial cable . 75Ω coaxial cable used in CATV network, it is known as CATV cable, transmission bandwidth of up to 1GHz, the most commonly used CATV cable transmission bandwidth of 750MHz. 50Ω coaxial cable is mainly used for base-band signal transmission, the transmission bandwidth of 1 ~ 2OMHz, bus, Ethernet is the use of 50Ω coaxial cable in the Ethernet, 50Ω thin coaxial cable with a maximum distance of 185 meters, thick coaxial cable up to 1000 meters.
