Coaxial cable is divided into four layers from inside to outside: central copper wire (single solid wire or multiple stranded wire),
plastic insulator, mesh conductive layer and wire outer skin. The central copper wire and the net conductive layer form a current loop. It is named for the coaxial relationship between the central copper wire and the reticulated conductive layer.
Coaxial cables conduct alternating rather than direct current, which means that the direction of current reverses several times per second.
If high-frequency current is transmitted by ordinary wires, such wires will be equivalent to an antenna that transmits radio outward. This effect loses the power of the signal and reduces the intensity of the received signal.
The design of coaxial cable is to solve this problem. The radio emitted by the central wire is isolated by a network conductive layer, which can control the radio emitted by grounding.
There is also a problem with coaxial cables. If a certain section of the cable is compressed or distorted, the distance between the central wire and the network conductive layer is not always the same, which will cause internal radio waves to be reflected back to the source of the signal. This effect reduces the received signal power. To overcome this problem, a plastic insulator is added between the central wire and the reticulated conductive layer to ensure that the distance between them remains the same. This also causes the cable to be rigid and not easy to bend.