In both work and personal life, consumers have come to expect instant data. Whether browsing the internet for recipes, watching YouTube videos, streaming movies on TV, or conducting a video conference call, the devices we use today call for data communications cables (twisted pair and coaxial) that support high transmission speeds with no interruption in service.
Cable manufactures seek material producers who supply compounds—for both insulation and jacketing— designed to support higher carrier frequency without essential losses. These specialized materials contribute to the overall design and performance of the cable in supporting high, uninterrupted data transmission.
The speed of data transfer for both wired and wireless systems relies on the electrical carrier frequency of the signal. Coaxial and twisted pair data communications cables, up to Category 8 (2 GHz), are designed to support increased transmission speed.
Along with specialized core components, the outer jacket and the insulation material chosen will play a role in supporting faster speeds without data loss or interference, as explained in the following discussion.
What types of cable are used for data transfer?
Data communications cables include twisted pair cable, which can be either unshielded or shielded and coaxial cable.
Although various constructions are used, in general, the copper conducting wires are covered with a polymer compound material that is an insulator, and the whole cable is covered with a polymer jacket.
The jacket both holds the core together and protects the cable from the environment, including keeping water out of the cable and slowing down burning of the cable if there were a fire.
How do jacketing and insulation materials affect data speed?
As electrical signals move from their source to their destination (either short or long distances, whether through a cable or through air) they experience signal loss, which is measured by attenuation (expressed in decibels [Db]).
When building a cable, manufacturers must choose jacket and insulation compounds that support minimized electrical loss.
Insulation materials are designed to have good electrical properties that minimize attenuation and provide proper, uniform impedance.
For best performance, insulation compounds are designed to have a low dielectric constant and a low dissipation factor.
The dielectric constant of a compound defines its electrical properties, such as impedance, and is affected by the polymer and other components in the formula. The dissipation factor is another electrical property that relates to attenuation and other types of signal loss.
The higher frequency used for faster data transmission creates a higher electromagnetic field, which can penetrate through insulation into jacketing; this dissipation of the signal causes data loss. Thus, for these higher category cables with faster data transmission, jacketing materials with a lower dissipation factor should be used.
Signal dissipation could also be reduced by increasing the diameter of the cable and the thickness of the insulation. In most situations, however, the outer diameters of cables are limited because the cables must fit with existing connectors.
Thus, instead of changing thickness, cable designers can choose insulation and jacketing materials with better dielectric properties. Material producers can provide data for dielectric constant and dissipation factor values on both insulation and jacket materials.
What other properties are important?
In addition to data speed, the flame retardancy and smoke suppression values are critical when designing data cables.
Depending on the country and application (whether in a public building, train, airplane, etc.), cables must pass certain flame and smoke tests.
Various types of flame retardants are added to jacketing and insulation compounds to help cables pass these tests.
Some flame retardants, however, have a detrimental effect on dielectric properties as well as on physical properties such as elongation and low-temperature brittleness.
Other ingredients can be added to the formula to improve these properties. Plastic Compounders with expertise in how polymers, fillers, and additives interact can formulate a cable compound to balance data speed, flame retardancy, and physical properties.