RF cable

RF cable is a cable that transmits electromagnetic energy within the RF range. RF cable is an indispensable component in various radio communication systems and electronic equipment, and is widely used in wireless communication and broadcasting, television, radar, navigation, computers and instruments. RF cable, also called coaxial cable, is composed of coaxial inner conductor, outer conductor and medium supporting inner and outer conductors. The characteristics of radio frequency cables include electrical and mechanical properties. Electrical properties include characteristic impedance, transmission loss and its frequency characteristics, temperature characteristics, shielding characteristics, rated power, maximum withstand voltage mechanical properties, including minimum bending radius, weight per unit length, maximum allowable tension, and aging characteristics and consistency of cables.

RF cable characteristics

1. It can transmit a wide frequency band; 2. High degree of defense against external interference; 3. Small antenna effect and radiation loss; 4. Simple structure, convenient installation and relatively economic.

RF cable classification

The structure of RF cable is diverse, and can be classified according to different ways and types. Classification by structure: (1) coaxial RF cable, coaxial RF cable is the most commonly used structure type. There are two types of commonly used RF coaxial cables: 50 Ω and 75 Ω RF coaxial cables. (2) Symmetrical RF cable. (3) Helical RF cable. Classification by insulation type: (1) Solid insulated cable. (2) Air insulated cable. (3) Semi-air insulated cable. Classified by insulating materials: plastic insulated cable, rubber insulated cable and inorganic mineral insulated cable. Classification according to flexibility: flexible cable, flat flexible cable, rigid cable, etc. Classified by transmission power: low power cables below 0.5 kW, medium power cables between 0.5 and 5 kW, and high power cables above 5 kW. Classified according to the characteristics of product use: low attenuation, low noise, micro and high stable phase cable, etc.

RF cable selection requirements

When selecting RF cable in practice, its characteristic impedance, rated power, attenuation and the maximum working voltage it can withstand should be considered. In the radio frequency transmission of radio communication, radio and television, it is necessary to combine the radio frequency impedance output by the transmitter, the output power, and the peak voltage that may be reached, and leave a certain margin, and select the appropriate cable in combination with the environmental conditions. It should be noted that when using RF cables, cable plugs, cable sockets, and coaxial change-over switches with the same characteristic impedance must be matched. They cannot be mixed to avoid causing large radio wave reflection and forming standing waves in the cable. When radio frequency cable is used in medium wave, because of its low working frequency and low loss, the radio frequency cable originally used in TV can be used in 50KW system in medium wave transmission system, but the current passing through the cable will be much greater than that of the TV system in meter wave band, so it is necessary to ensure that the cable head and cable socket are in good contact indirectly, otherwise it will cause failure due to overheating.