The coaxial cable, or coax cable, is a shielded cable that is bipolar and concentric by design. It has an internal conductor (core), which is evenly spaced from a hollow cylindrical external conductor (see Cable shield). The two conductors are separated by an insulator or a dielectric, which can consist entirely of air.
Coaxial cables are used to transmit signals (e. g. laboratory and measuring instruments) and for broadband communication (e. g. transmitters, antennas). See Fig. 1 Shielded cable