(1) coaxial RF cable
Coaxial RF cable is the most common type of structure. Because the internal and external conductors are in concentric position, the electromagnetic energy is confined in the medium between the inner and outer conductors, so the utility model has the advantages of small attenuation, high shielding performance, wide frequency band usage and stable performance. Radio frequency energy typically used to transmit 500 kHz to 18 thousand mhz.
At present, the commonly used radio frequency coaxial cable has two kinds: 50 and 75 radio frequency coaxial cable. Characteristic impedance 75, RF coaxial cable is commonly used in CATV networks, so called CATV cable, transmission bandwidth of up to 1GHz, the current CATV cable transmission bandwidth of 750MHz.
(2) symmetrical radio-frequency cable
Symmetrical radio frequency cable loop has an open electromagnetic field. Because of the radiation electromagnetic energy at high frequency, the attenuation is increased, and the shielding performance is poor, and the influence of atmospheric condition is usually less used. Symmetrical radio frequency cables are mainly used in low frequency radio or symmetrical feeding.
(3) helix radio frequency cable
The coaxial cable in the symmetric or, sometimes made of spiral coil, inductance to cable increases, thereby increasing the wave impedance of the cable and the transmission delay time of electromagnetic energy, the former is called high resistance cable, the latter is called delay cable. If the spiral coil varies in length along the length, it can be made into a variable resistance cable.