Coaxial cable is mainly a cable with two concentric conductors, while the conductor and the shield share the same axis of cable. The most common coaxial cable consists of insulated copper conductor. Inside the insulating layer is another layer of ring conductor and its insulator. Then the whole cable is covered by PVC/PE or Teflon sheath.
Coaxial cable can be divided into two basic types, baseband coaxial cable and broadband coaxial cable. Baseband coaxial cable is the longest cable use, it has high bandwidth and excellent noise suppression, so is widely used in digital transmission and analog transmission. As a result, broadband coaxial system is widely used because of its wide coverage area.
The advantages of the coaxial cable can support high bandwidth communication in relatively long without repeater on the line, but the drawback is obviously: It is a large volume, the cable is thick and big, occupies a lot of space; Two is it cannot withstand the entanglement, pressure and serious bending, which will damage to the cable structure, stop signal transmission; the last is the high cost. But the twisted pair can be overcome all those shortcomings, so now in the LAN environment, it has been based on Ethernet physical layer specification of twisted pair instead.
Because coaxial cable has many advantages, such as easy installation, low cost, strong anti-interference ability and reliability, it is widely used in network transmission of signal transmission.