Coaxial cables are higher-grade cables designed to meet specific impedances and transmit higher-quality signals, which can work at higher frequencies and data rates. A coaxial cable contains two conductors located in the center of the same axis. The coaxial cable contains an internal signal wire, which is usually made of copper and wrapped with a dielectric material. The central conductor and insulator wrap the shielding layer or grounding conductor and the insulating shell or sheath.
The gap between the external ground conductor and the internal conductor is very important, and this gap must be maintained throughout the cable. The ratio between the diameter of the inner wire and the outer ground shielding layer and dielectric material is the parameter and characteristic that determines the specific impedance of the cable. The specific impedance determines whether high-frequency signals can be effectively transmitted through the cable without or almost no degradation.
Coaxial cables are often used for radio frequency and radio transmission, antenna feeders, Internet and interconnect cables. Currently, they are also used in high-end electronic test equipment for detecting high frequency signals. They are often used for network analysis, connecting with vector network analyzers and related networks.
From: https://www.dosinconn.com/use-coaxial-cable/
