RF Coaxial Cable Materials Analysis: Cost-Effective Selection Guide

Since 2025, prices of copper, gold, silver, and tin have surged sharply: copper by 48%, gold by approximately 100%, silver by around 200%, and tin by roughly 90%. This has exerted a tremendous impact and driven significant price increases for both RF coaxial cables and connectors. This document aims to analyze and list the material composition of cables, providing a reference for customers during product selection to choose the most cost-effective solutions.

Radio Frequency (RF) coaxial cable is a transmission line composed of inner and outer conductors with a dielectric medium in between, operating primarily in the TEM mode with a frequency range covering DC to millimeter waves. It features low radiation loss and excellent anti-interference performance. The cable typically consists of four structural layers: center conductor, dielectric insulation, Outer Conductor, and outer jacket. The Outer Conductor achieves electromagnetic shielding through grounding. In addition, special structures such as Triaxial and Twinax cables are also available.

I. Materials of the Center Conductor

1. Copper Clad Steel (CCS)

Copper clad steel wire is a composite conductor made by cladding a layer of copper onto a steel core. It combines the mechanical properties of steel—high strength and resistance to high-temperature softening—with the electrical properties of copper—high conductivity and low contact resistance. As such, it offers high transmission efficiency, low material cost, high tensile strength, light weight, and wear resistance. In the cable industry, it can replace copper conductors for high and low-frequency communication cables.

By integrating steel’s high strength with copper’s high conductivity and corrosion resistance, CCS has become an ideal conductor for communications, power, and electronics. A thicker copper cladding results in higher DC conductivity.

CCS is classified by conductivity into three grades: 21% IACS, 30% IACS, and 40% IACS (IACS = International Annealed Copper Standard). By mechanical properties (annealed condition), it is divided into soft (A), hard (HS), and extra-hard (EHS). Generally, RF cables use soft-state CCS of 30% or 40% IACS as the inner conductor.

2. Silver Plated Copper (SPC)

Silver plated copper wire is produced by concentrically plating a layer of silver onto a copper core. It integrates the advantages of both copper and silver, delivering excellent electrical conductivity, a bright surface finish, and exceptional corrosion resistance from the silver layer. These advantages make SPC the preferred material for high-frequency cables.

Silver plated copper wire is categorized into soft and hard types. Soft silver plated copper wire undergoes annealing to modify its physical properties for increased flexibility. High-quality SPC features a continuous and firmly bonded silver layer that does not darken under testing, with a smooth, defect-free surface free of silver particles, burrs, or mechanical damage.

Key characteristics include high conductivity, outstanding high-frequency performance (widely used in high-performance cables such as low-loss SUJ series and test-grade KBA series), and high-temperature resistance with an operating range of -60℃ to +250℃, along with excellent corrosion resistance.

3. Tinned Copper (TC)

Tinned copper features a thin layer of tin plated onto the copper surface. Tin forms a tin oxide film in air, preventing copper oxidation; it also forms a similar protective film against halogens. Thus, tinned copper provides good corrosion resistance, adequate strength and hardness, good formability, and excellent solderability. The tin layer is non-toxic, odorless, and bright.

The primary purpose of tin plating is to prevent copper oxidation. In cable assemblies, tinned copper is used as an inner conductor but is more commonly selected for the outer conductor, such as tinned copper braiding in semi-flexible cables.

4. Copper Clad Aluminum (CCA)

Copper clad aluminum is a bimetallic composite conductor with an aluminum core and outer copper cladding, mainly used as the inner conductor for CATV subscriber and drop cables. Leveraging the skin effect at high frequencies, it achieves high-frequency transmission performance comparable to pure copper while significantly reducing material cost and weight.

Mechanically, it is flexible and weighs only 37%–40% of pure copper, facilitating transportation and installation. Electrically, its DC resistivity is approximately 1.5 times that of pure copper, but its AC resistance is lower, effectively improving heat dissipation.

5. Bare Copper (BC)

Bare copper wire is a copper-based conductor with conductivity second only to silver at a lower cost, serving as a core material for power transmission and electronic equipment. In coaxial cables, it is commonly used as solid or stranded bare copper wire.

II. Material of dielectric Insulation

• Foamed Polyethylene (FOAM PE): Low loss, lightweight, cost-effective, suitable for RF signal transmission.

• Solid Polyethylene (Solid PE): Good mechanical strength, easy processing, low cost; however, higher dielectric constant and greater loss than foamed PE, with average high-frequency performance.

• Polytetrafluoroethylene (PTFE): Extremely low dielectric loss, high temperature resistance, corrosion resistance, and excellent high-frequency performance.

• Fluorinated Ethylene Propylene (FEP): A modified PTFE material, melt-processable, with low high-frequency loss, temperature resistance, weather resistance, and easy molding.

• Low-Density Polytetrafluoroethylene (LD-PTFE): Porous PTFE structure with low dielectric constant and loss; lighter, lower-loss, and more flexible than standard PTFE, but higher cost, lower mechanical strength, and complex processing.

III. Outer Conductor

• Copper Clad Aluminum (CCA)

• Copper Clad Steel (CCS)

• Tinned Copper (TC)

• Bare Copper (BC)

• Silver Plated Copper Strip: Excellent high-frequency shielding, corrosion and high-temperature resistance; high cost, used mainly in military and high-end test applications.

• Aluminum-Plastic Foil: Extremely low cost, effective electric field shielding, tight wrapping.

• Copper-Plastic Foil: Superior shielding to aluminum-plastic foil, good solderability, but higher cost.

• Stainless Steel Wire: Ultra-high strength, corrosion resistance, tensile and damage resistance; non-solderable.

• Copper Tube: Can be tinned, ternary-plated, or nickel-plated; optimal shielding performance, stable structure, good air-tightness, and strong anti-interference. However, it is inflexible, rigid, heavy, and complex to process, mainly used in semi-rigid and high-performance cables.

• Aluminum-Magnesium Alloy Wire: Low density (about one-third of copper wire), lightweight, significantly reducing overall cable weight and material cost with higher cost-effectiveness than copper. High strength and toughness, maintaining stability and flexibility at high temperatures (120℃) without deformation. Excellent corrosion resistance, especially in harsh environments such as seawater and industrial atmospheres, with superior acid and alkali resistance and longer service life than copper. Better shielding effect than copper, effectively replacing copper for shielding braiding in low-voltage cables. Also provides good thermal conductivity to assist cable heat dissipation.

IV. Outer Jacket

• Polyethylene (PE): Water-resistant, weather-resistant, low-cost, flexible; poor flame retardancy, low temperature resistance, and poor oil resistance.

• Polyvinyl Chloride (PVC): Extremely low cost, flame retardant, flexible, easy processing; low temperature resistance, prone to hardening and brittleness at low temperatures.

• Fluorinated Ethylene Propylene (FEP): High temperature resistance, oil resistance, chemical corrosion resistance, low dielectric loss; relatively high hardness.

• Thermoplastic Elastomer (TPE): High flexibility, bending resistance, environmentally friendly, good hand feel; medium temperature and weather resistance.

• Polyurethane (PUR): Wear-resistant, oil-resistant, hydrolysis-resistant, tear-resistant, ultra-flexible; relatively high cost.

• PTFE Fiber Jacket: High temperature resistance, chemical corrosion resistance, extremely low dielectric loss, high strength; expensive, Usually used as armor jacket for high-end test cables.

• Cross-Linked Ethylene Tetrafluoroethylene (X-ETFE): High temperature resistance, radiation resistance, aging resistance, high mechanical strength; aerospace-grade material with very high cost, widely used in aerospace and other fields requiring extreme temperature and radiation resistance.

Selection Example:

Standard Configuration for LMR300 Coaxial Cable

- Inner Conductor: BC (Bare Copper)

- Insulation Dielectric: Foam PE (Foamed Polyethylene)

- Outer Conductor: Aluminum tape / Tinned copper

- Jacket: PE / PVC

For Cost-Effective, Lightweight Products with Equivalent Electrical Performance, the Configuration is:

- Inner Conductor: CCA (Copper Clad Aluminum)

- Insulation Dielectric: Foam PE (Foamed Polyethylene)

- Outer Conductor: Aluminum tape / Tinned copper clad aluminum

- Jacket: PE / PVC

The End.