Classification method of RF coaxial cable

The structure of RF cables is varied and can be categorized according to different methods and types.

First, according to cable structure classification

(1) Coaxial RF cable

Coaxial RF cables are the most common type of construction. Since the inner and outer conductors are in a concentric position, the electromagnetic energy is confined to propagate in the medium between the inner and outer conductors, so that it has the advantages of small attenuation, high shielding performance, use frequency bandwidth and stable performance. Usually used to transmit RF energy from 500 kHz to 18 GHz.

Currently, there are two types of commonly used RF coaxial cables: 50Ω and 75Ω RF coaxial cables. The characteristic impedance 75Ω RF coaxial cable is commonly used in CATV networks, so it is called CATV cable, and the transmission bandwidth can reach 1GHz. Currently, the transmission bandwidth of common CATV cable is 750MHz.

(2) Symmetrical RF cable

Symmetrical RF cable circuits have an open electromagnetic field. Due to the radiant electromagnetic energy at high frequencies, the attenuation is increased and the shielding performance is poor. In addition, the influence of atmospheric conditions is often used. Symmetrical RF cables are primarily used in the case of low RF or symmetric feeds.

(3) Spiral RF cable

The conductor in the coaxial or symmetrical cable can sometimes be made into a spiral coil shape, thereby increasing the inductance of the cable, thereby increasing the wave impedance of the cable and delaying the transmission time of the electromagnetic energy. The former is called a high resistance cable, and the latter is called a high resistance cable. For delay cables. If the spiral coils are wound at different densities in the length direction, a varistor cable can be made.

Second, according to insulation type classification

(1) Solid insulated cable

The solid high frequency dielectric is filled between the inner and outer conductors of such a cable, and most of the soft coaxial RF cables use this type of insulation.

(2) Air insulated cable

In the insulation layer of the cable, most of the volume is air except for a part of the solid medium supporting the inner and outer conductors. Its structural feature is that it does not pass through the dielectric layer from one conductor to the other. Air insulated cables have very low attenuation and are a common type of structure used at ultra high frequencies.

(3) Semi-air insulated cable

This type of construction is an insulation type between the two, the insulation is also a combination of air and solid medium, but from one conductor to the other through the solid medium layer.

Third, according to insulation materials classification

Plastic insulated cable, rubber insulated cable and inorganic mineral insulated cable.

Fourth, according to softness classification

Divided into soft cable, flat cable and rigid cable.

V. Classification by transmission power

It is divided into low power of 0.5 kW or less, high power cable of 0.5~5 kW medium power and 5 kW or more.

6. Classification according to product use characteristics

Divided into low attenuation, low noise, micro-small and stable phase cable.