- Insulation medium of coaxial cable structure and material
The medium of radio frequency coaxial cables is far more than just insulating. The final transmission performance is mainly determined after the insulation. Therefore, the choice of dielectric material and its structure are very important. All important properties, such as attenuation, impedance and return loss, have a lot to do with insulation. The most important requirements for insulation are:
Low relative permittivity and small dielectric loss angle factor to ensure small attenuation; consistent structure to ensure uniform impedance and large return loss; stable mechanical properties to ensure long life; waterproof and moisture-proof.
2. Sheath of coaxial cable structure and material
The most commonly used sheath material for outdoor cables is black linear low-density polyethylene, which is similar in density to LDPE but comparable in strength to HDPE. On the contrary, in some cases, we tend to use HDPE, which can provide better mechanical properties and resistance to friction, chemicals, moisture and different environmental conditions for the jacket.
UV-resistant black HDPE can withstand climatic stresses such as extremely high temperatures and strong UV rays. When emphasizing the fire safety of cables, low-smoke, halogen-free and flame-retardant materials should be used. In leaky cables, in order to reduce the spread of fire, a fire-resistant and flame-retardant tape can be used between the outer conductor and the sheath, so that the insulating layer that is easy to melt remains in the cable.
