What is Coaxial Cable?

What is Coaxial Cable?

Coaxial cable, often referred to as coax, is a type of electrical cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. Its name derives from the term ‘coaxial’, which refers to the common axis of the two conductors. This unique design allows the cable to carry an electric signal with minimal losses due to electromagnetic interference, making it a popular choice for a wide range of applications.

The Structure of Coaxial Cable

Coaxial cable is a two-conductor transmission line with an outer metal tube or a central conductor surrounded by a mesh shield. The inner conductor is supported by a kind of dielectric insulation, which can be solid, expanded plastic or semi-solid. It supports semi-solid polyethylene discs, helical tapes, or helically wrapped plastic tapes. In some designs, insulating beads, support pins, or periodically bent plastic tubes are used.

The important feature of the coaxial cable is that it has a shielded structure. This means that the inner conductor (or core) and the outer shield share the same geometric axis. The electromagnetic field associated with each Coaxial unit is nominally limited by the space between the inner and outer conductors. This design helps to protect the signal traveling through the cable from external interference, which can degrade the signal quality.

The History of Coaxial Cable

Coaxial cable has a rich history that dates back to the early 20th century. In the 1930s, it served as the transport of high-frequency electrical signals with two concentric conductors, called the central, responsible for carrying information, and the return of a tubular appearance, ground reference, and currents, called lattice or protection.

Between the two is an insulating layer called a dielectric, the properties of which depend mainly on the quality of the cable. The whole set is usually protected by an insulating cover. This design was revolutionary at the time, as it allowed for the efficient transmission of signals over long distances with minimal loss.

The Properties of Coaxial Cable

There are three general types of Coaxial cables, flexible, semi-rigid, and rigid for different applications. In general, the harder the cable, the electrical properties will be more stable and predictable. It is important that the loss in a cable is low, as the loss in a transmission line increases approximately with the frequency rating.

Also, physical and electrical irregularities, especially if they are periodic, should be kept to a minimum or coaxial transmission loss at certain frequencies will be very high. This is why the manufacturing process of coaxial cables is highly controlled to ensure consistent quality and performance.

The Use of Coaxial Cable

The main use of this cable is the transmission of high-frequency broadband signals. These cables use the frequency of sound very little because their protection properties are poor. They are also more expensive than twisted pairs with the same transmission loss.

However, the superior performance of coaxial cables in terms of signal integrity and resistance to interference makes them a preferred choice for applications that require high data rates or long-distance transmission. This includes cable television, internet networks, and radio broadcasts, among others.

The Types of Coaxial Cable

There are multiple types of coaxial cables, each with a different diameter and impedance. The coaxial cable is normally not affected by external interference and can reach high transmission speeds over long distances. Therefore, it is used in Broadband communication networks (television cable) and baseband cables (Ethernet). The type of cable to be used depends on the position of the cable.


Coaxial cable is more resistant to interference and attenuation than twisted-pair cable, so they were more preferred. Wire mesh prevents lost electronic signals, so it does not affect data sent from the internal cable. Therefore, the coaxial cable is a good choice to reliably support large amounts of data with a simple system for long distances.

In conclusion, the coaxial cable is a versatile and reliable solution for transmitting electrical signals. Its unique design and properties make it an ideal choice for a wide range of applications, from home entertainment systems to high-speed data networks. As technology continues to evolve, it is likely that the use of coaxial cable will continue to grow and adapt to meet the needs of future applications.

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