1: 50MHz attenuation constant is too large or excessive, and high-frequency margin, often too low conductivity or aluminum-plastic composite aluminum strip is too thin due to the low frequency, the aluminum Of the thickness is less than or equal to the transmission depth of the frequency, resulting in? R is too large. According to theoretical calculations, f = 50MHz when the aluminum layer transmission depth of 12.2μm. Generally take 12 ~ 15μm aluminum can solve this problem. (Of course, if taking into account the requirements of shielding attenuation can be appropriately thickened)
2: select the PE in the use of frequency tanδ larger, such as to x × 10-3 level, it will cause the tanδ insulation structure increases, so that the attenuation of the cable increases. So pay attention to two issues, one tanδ small (such as the tanδ at 400MHz 2 ~ 4 × 10-4, the smaller the better), one process performance (such as the melt index of 0.5 to 10) should be suitable for insulation Of the extrusion, different melt index has a different temperature.
3: Outer conductor weaving generally 60% -80% is appropriate, too large to reduce the attenuation effect is not very obvious.
4: Insulation production with the mold design and processing is the key, it should ensure that the product to achieve a more uniform structure, the equivalent of the medium constant reach the design requirements.
5: physical foam PE attenuation in the low frequency is qualified, and high frequency (such as more than 800MHz) when the tolerance, mostly with the dielectric loss tangent and the equivalent dielectric constant is too large a relationship, or with the outer conductor braid density Small, the outer diameter of the inner conductor has a relationship. In addition, the attenuation constant also depends on the size of the degree of foaming. Increase the degree of foaming (increase the degree of foaming, increase the impedance, and decrease the attenuation) within the allowable range of impedance and echo to improve the decay constant of the cable, and also reduce the cost.