Coaxial cables, often referred to as “coax”, are a type of electrical cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. They are used as a transmission line for radio frequency signals, with applications including feedlines connecting radio transmitters and receivers to their antennas, computer network connections, digital audio, and distribution of cable television signals.
Structure of Coaxial Cables
Coaxial cables are composed of an inner core, an insulating layer, a conductive shielding, and an outer cover[^2^].
The copper conductor is the central part of the cable where the data transmits.
The insulator is a dielectric plastic insulation around the copper conductor. It is used to maintain the spacing between the center conductor and shield.
The braided mesh of copper helps to shield from electromagnetic interference. The braid provides a barrier against EMI moving into and out of the coaxial cable.
Protective Plastic Layer
The protective plastic layer is an external polymer layer, which has a plastic coating. It is used to protect internal layers from damages.
Types of Coaxial Cables
There are several types of coaxial cables, each designed for specific applications[^4^].
Hardline Coaxial Cable
Hardline coaxial cables have a center conductor made of copper, silver, and have a larger diameter when compared to other coaxial cables.
Flexible Coaxial Cable
Flexible coaxial cables are very flexible and the inner conductor is surrounded by a flexible polymer.
Semi-Rigid Coaxial Cable
Semi-rigid coaxial cables use a solid copper outer sheath with a dielectric of Polytetrafluoroethylene.
Formable Coaxial Cable
Formable coaxial cables are an alternative to semi-rigid cable, instead of a rigid copper outer sheath a flexible metal sheath is utilized.
Twinaxial cables have two central conductors in the core and a single outer core and dielectric. These cables are best for low-frequency digital and video transmission.
Triaxial cables, also known as Triax, are similar to a coaxial cable but with an additional copper braid added to it. The braid works as a shield and protects from noise. Triaxial cables offer more bandwidth.
Rigid Coaxial Cable
Rigid coaxial cables are made up of two copper tubes supported at cable ends and fixed intervals across the length of the cable using PTFE supports or disk insulators. The rigid coaxial cable cannot be bent. It is mainly used in TV and FM broadcasting systems.
Applications of Coaxial Cables
Coaxial cables are used in a variety of applications, including:
- Ethernet LANs and MANs: Coaxial cables are used in Ethernet Local Area Networks (LANs) and Metropolitan Area Networks (MANs).
- Television: Coaxial cable used for television would be 75 Ohm and RG-6 coaxial cable.
- Internet: Coaxial cables are also used for carrying internet signals, RG-6 cables are used for this.
- CCTV: The coaxial cables are also used in CCTV systems and both RG-59 AND RG-6 cables can be used.
- Video Transmission: The coaxial cables are also used in video Transmission the RG-6 is used for better digital signals and RG-59 for lossless transmission of video signals.
- HDTV: The HDTV uses RG-11 as it provides more space for signals to transfer.
Advantages of Coaxial Cables
Coaxial cables offer several advantages, including:
- High Bandwidth: Coaxial cables support high bandwidth.
- Easy Installation: It is easy to install coaxial cables.
- Reliability and Durability: Coaxial cables have better cut-through resistance so they are more reliable and durable.
- Less Noise Interference: They are less affected by noise or cross-talk or electromagnetic inference.
- Support for Multiple Channels: Coaxial cables support multiple channels.
Disadvantages of Coaxial Cables
Despite their advantages, coaxial cables also have some disadvantages:
- Cost: Coaxial cables are more expensive than other types of cables.
- Bulky: Due to their multiple layers, coaxial cables are very bulky.
- Security Risks: There is a chance of breaking the coaxial cable and attaching a “t-joint” by hackers, this compromises the security of the data.
Coaxial Cables vs. Other Cables
Coaxial cables are often compared to other types of cables, such as twisted pair cables and fiber optic cables. For example, coaxial cable can be cabled over longer distances than twisted-pair cable. For instance, Ethernet can run approximately 100 meters (328 feet) using twisted-pair cabling. Using coaxial cable increases this distance to 500m (1640.4 feet).
In conclusion, coaxial cables are a versatile and widely used type of cable for transmitting radio frequency signals. They offer several advantages, such as high bandwidth, easy installation, and less noise interference. However, they also have some disadvantages, including higher cost and potential security risks. Despite these drawbacks, their wide range of applications and superior performance make them a popular choice for many types of communication links.