The coaxial cable is divided into four layers from the inside to the outside: the Central copper wire (the single strand of solid or stranded strands), the plastic insulator, the reticular conductive layer and the wire skin. The central copper wire and the reticular conductive layer form a current loop. Because the central copper wire and the reticular conductive layer are named for the coaxial relation.
The coaxial cable conducts alternating currents rather than direct current, which means that several times a second are reversed.
If you use a general wire to transmit high frequency currents, the wire will be equivalent to an antenna that emits a radio outward, which loses the power of the signal and reduces the strength of the signal received.
The coaxial cable is designed to solve this problem. The radio emitted by the center wire is isolated by the reticular conductive layer, and the reticular conductive layer can control the emitted radio through grounding.
There is also a problem with coaxial cable, that is, if a certain section of cable has a large extrusion or distortion, then the distance between the center wire and the reticular conductive layer is not consistent, which causes the internal radio waves to be reflected back to the signal sending source. This effect reduces the signal power that can be received. To overcome this problem, a layer of plastic insulation is added between the center wire and the reticular conductive layer to ensure that the distance between them is consistent. This also caused the cable to be relatively stiff and not easy to bend the characteristics.