The most important electrical properties of the electric cable is low attenuation, impedance uniformity, high return loss, the leakage cable also very key point is its best coupling loss. The main effect of the cable is a transmission signal, therefore, should the cable structure and materials to ensure cable throughout deadline has good transmission characteristics, it is very important. Here follow the Hong Kong Asian senior cable engineers to learn to master the professional knowledge.
1, The inner conductor
Copper is the main material of the inner conductor, it may be the following forms: annealed copper, annealed brass, copper clad aluminum wire. Typically, a small cable conductor is copper or copper-clad aluminum, brass and large cable to reduce cable weight and cost. Large cable outer conductor corrugations, so get good enough bend performance.
A great influence on the inner conductor signal transmission, because the inner conductor attenuation is mainly caused by resistive losses. Conductivity, especially surface conductivity, should be as high as possible, generally require a 58MS / m (+ 20 ℃), because at high frequencies, the current only in a thin layer of the transmission conductor surface, a phenomenon known as the effective thickness of the skin effect, the current layer is called the skin depth. Quality copper inner conductor with the demanding requirements of copper should be no impurities, the surface clean, flat and smooth. Conductor diameter should be stable and within narrow tolerances. Any changes will reduce the diameter of a uniform impedance and return loss, and should therefore be precisely controlled manufacturing process.
2, The outer conductor
The outer conductor of cable wires has two basic functions: the first is the role of the loop conductor, and the second from the shielding effect. Leaky cable outer conductor also determines its leakage performance. The outer conductor of the coaxial feeder cable and the cable is super soft embossed brass welded together, the outer conductor of these cables completely closed, allowed cable have any radiation.
Portrait of the outer conductor is usually made by a copper cladding. The outer conductor layer, has opened a longitudinal or transverse notches or holes.
Slotted outer conductor cables in emboss more common. Along the axial direction of the roll ripple peaks are formed equidistant cutting slot. Part of a small proportion of slashing and slot spacing is much smaller than the electromagnetic wavelength transmission.
Clearly, the non-leaky cable processing can be made by the following method leaky cable: 120-degree angle on the non-leakage type cable commonly common cable outer conductor wrinkles peak cutting, to obtain a suitable slot structure. Leaky cable shape, width and slot structure determines its performance.
The outer conductor of copper should be of good quality, high conductivity, no impurities. Outer conductor size should be strictly controlled within the tolerance range, in order to ensure uniform characteristic impedance and high return loss.