Material selection is one of the most critical decisions in RF coaxial connector design. The chosen metal or insulator directly affects the connector’s mechanical strength, electrical performance, environmental resistance, power handling, and cost. Understanding material characteristics is essential for engineers to balance performance with reliability and manufacturability.

This guide explains the most commonly used materials for RF coaxial connectors—including both metal and non-metal components—and how each material impacts connector performance.

Main body（Coupling nut、Barrel）

Contact pin（inner conduct）

Common Metal Materials Used in RF Connectors

Metal components form the conductive path of an RF connector, ensuring low-loss transmission and reliable mechanical engagement. The most commonly used metals include beryllium bronze, tin-phosphor bronze, brass, stainless steel and aluminum alloys.

Beryllium bronze

✔ High conductivity | ✔ Heat-resistant | ✔ Excellent elasticity

• Strong electrical and thermal conductivity

• Excellent fatigue resistance and corrosion resistance

• Maintains elasticity and strength even at high temperature

Common applications: jack contacts, flexible contacts, precision outer conductors

Tin-phosphor bronze

✔ Cost-efficient alternative to BeCu | ✔ Good formability

• Softer than beryllium bronze → suitable for press-forming and bending

• Often used as a lower-cost option where high elasticity is not required

Used for: larger jacks, flexible contacts, outer interface conductors

Brass

✔ Easy machining | ✔ Good conductivity | ✔ Corrosion-resistant after plating

• Known as "free-cutting brass" → excellent machinability

• Often plated with Ni/Ag/Au or ternary alloy to enhance durability

Common uses: connector housings, barrels, pins, outer conductor bodies

Stainless steel

✔ High hardness | ✔ Excellent corrosion resistance

• Used where structural strength and durability are essential

• High melting point and environmental resistance

Applications: connector shells, outer conductor bodies for rugged environments

Aluminum alloys

✔ Lightweight | ✔ Good machining properties | ✔ Cost-efficient

• Commonly used as Anticorodal alloy

• Offers good electrical performance, heat transfer, corrosion resistance

• Suitable replacement for brass or stainless steel in weight-sensitive designs

Used for: outer protective shells, structural components

Comparison of common material properties

 Note: Relative values range from ++ (very good/very low price), + (better/low price), 0 (fair), - (poor) to -- (very poor/very high price).

*Contact resistance must be as small as possible (++ very low, perfect)

Insulator

Seals

Non-Metal Materials for Insulation & Sealing

RF connector insulators and seals use high-performance plastic and rubber materials that provide stability at high frequencies and harsh environments.

PTFE (Polytetrafluoroethylene)

✔ Best dielectric properties | ✔ -200°C to +250°C stability

• Excellent high-frequency electrical performance

• Non-flammable, anti-adhesive, chemically inert

Used in: insulators, dust caps, precision tools

PFA (Perfluoroalkoxy)

✔ Thermoplastic (moldable) version of PTFE

• Injection-moldable → ideal for mass production

• High temperature resistance (-200°C to +250°C)

• Better wear resistance vs PTFE

Used in: insulators, cable jackets

PEEK (Polyetheretherketone)

✔ Extreme mechanical strength | ✔ Low dielectric loss

• High melting point (334°C)

• Radiation-resistant, chemically stable

• Excellent for high-frequency connectors

Used in: high-power insulators, aerospace-grade connector components

Silicone Rubber

✔ Sealing & environmental protection

• Mainly used as gasket and sealing material

• Flame-retardant and moisture-proof

• Prevents dust, liquid and gas intrusion

Used for: seals, O-rings, environmental gaskets

Comparison of ordinary plastic and silicone rubber

Note: Relative values range from ++ (very good/very low price), + (better/low price), 0 (fair), - (poor) to -- (very poor/very high price).