Question

When a small electrical signal must travel a distance, a shield cable is used in which the signal wire is surrounded by an insulator and the enclosed by a cylindrical conductor that carries a return current. What is the advantage of this coaxial cable design?  

Answer 1

Coaxial cable is a type of transmission line, used to carry high frequency electrical signals with low losses. It is used in such applications as telephone trunklines, broadband internet networking cables, high speed computer data busses, carrying cable television signals, and connecting radio transmitters and receivers to their antennas. It differs from other shielded cables because the dimensions of the cable and connectors are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a transmission line.

Due to skin effect, coaxial cable is used in high frequency applications (> 50 MHz) using copper clad materials for center conductor. Skin effect is result of high frequency signals propagating along outer surface of the conductor. It increases tensile strength of the cable and reduces weight.
➨The cost of coaxial cable is less.
➨The outer conductor in coaxial cable is used to improve attenuation and shield effectiveness. This can be further enhanced with the use of second foil or braid known as jacket (C2 as designated). The jacket is used as protective cover from the environment and makes overall coaxial cable as flame retardant.
➨It is less susceptible to noise or interference (EMI or RFI) compare to twisted pair cable.

➨It supports high bandwidth signal transmission compare to twisted pair.
➨It is easy to wire and easy to expand due to flexibility.
➨It allows high transfer rates with coaxial cable having better shielding materials.