A coaxial cable is made of a central copper conductor, a dielectric insulating layer, a braided metal shield, and an outer protective plastic jacket.

Core Conductor

The innermost part of a coaxial cable is the central conductor, typically made of solid copper or copper-clad steel. This conductor carries high-frequency electrical signals and is chosen for its excellent conductivity, ensuring minimal signal loss over long distances and reliable data transmission .

Dielectric Insulator

Surrounding the central conductor is a dielectric layer, which is a non-conductive insulating material. Common materials include polyethylene (PE), foam plastic, polypropylene, polyvinyl chloride (PVC), or fluoroplastics like Teflon (PTFE). This layer maintains the spacing between the inner conductor and the outer shield, preserving signal integrity and minimizing energy loss .

Braided Shield (Outer Conductor)

Encasing the dielectric is a braided metal shield, usually made of copper or aluminum. This shield serves as the outer conductor and provides two main functions: it acts as a return path for the signal and protects the cable from electromagnetic interference (EMI) and radio frequency interference (RFI), ensuring the signal remains stable over long distances .

Protective Outer Jacket

The final layer is the outer protective jacket, typically made from PVC or other durable polymers. This sheath protects the internal components from environmental damage, such as moisture, abrasion, and physical stress, while also enhancing flexibility for indoor or outdoor use .

Summary

In essence, a coaxial cable's structure consists of four main layers: the copper core for signal transmission, the dielectric insulator for spacing and signal integrity, the braided metal shield for EMI protection, and the outer plastic jacket for mechanical protection. This layered design allows coaxial cables to transmit high-frequency signals efficiently and reliably over long distances .