Coaxial rf cable is the most commonly used structure. Due to the concentric position of the inner and outer conductors, electromagnetic energy is confined to the medium between the inner and outer conductors. Therefore, it has significant advantages such as small attenuation, high shielding performance, wide frequency band and stable performance. It is usually used to transmit radio frequency energy from 500 KHZ to 18 gigahertz.
Commonly used at present, there are two types of coaxial cable of the radio: 50 Ω and 75 Ω coaxial cable of the radio. Characteristic impedance of 75 Ω rf coaxial cable used in CATV network, so called CATV cable, transmission bandwidth can reach 1 GHZ, current CATV cable transmission bandwidth of 750 MHZ.
