Structural Classification Of RF Cables

- Dec 20 2017 - (1) coaxial radio frequency cable

Coaxial radio frequency cable is the most commonly used structure type. Due to the concentric position of its inner and outer conductors, the electromagnetic energy is limited to the medium between the inner conductor and the outer conductor, so it has the advantages of small attenuation, high shielding performance, wide frequency band and stable performance. It is usually used to transmit radiofrequency energy from 500 kHz to 18 thousand MHz.

At present, there are two types of RF coaxial cables: 50 omega and 75 Omega RF coaxial cables. The characteristic impedance 75 Omega RF coaxial cable is commonly used in CATV network, so it is called CATV cable, the transmission bandwidth can reach 1GHz, and the transmission bandwidth of CATV cable is 750MHz at present.
(2) symmetrical radio frequency cable

The electromagnetic field of the symmetrical radio frequency cable circuit is open. Because of the radiated electromagnetic energy at high frequency, the attenuation is increased, resulting in poor shielding performance, coupled with the influence of atmospheric conditions. Symmetric radio frequency cables are mainly used in the case of low RF or symmetrical feed.

(3) spiral radio frequency cable

Conductors in coaxial or symmetrical cables can sometimes be made into spiral coils so as to increase the inductance of cables, thereby increasing the wave impedance of cables and the transmission time of delayed electromagnetic energy. The former is called high resistance cable, and the latter is called delayed cable. If the coil's density is different in the direction of the length, a variable resistance cable can be made.