Materials Matter in RF Performance
The materials used in RF connectors directly influence their electrical performance, mechanical strength, environmental durability and cost efficiency. Every component, from the connector body to the contact pins and dielectric, is carefully selected to ensure optimal signal integrity, long service life and suitability for the intended application.
This guide outlines the most common materials used across Amphenol RF products and explains how their properties impact performance, helping engineers and buyers make informed design choices.
Dielectric (Insulator) Materials
Dielectrics maintain the precise spacing between the center conductor and connector body, which is a key factor in impedance control and high-frequency performance. The choice of dielectric affects signal loss, temperature stability and manufacturability.
| Dielectric Material | Typical Uses | How It's Processed | Key Characteristics & Benefits | Considerations | Noteworthy Attributes |
| PTFE | Most common dielectric in RF connectors | Machined or molded into precision shapes | Low dielectric constant, wide temp range | More challenging to machine and limited mechanical rigidity. | Standard in most RF connectors |
| Delrin | Insulator for mid-range commercial connectors | Injection molded | Good machinability, low moisture absorption | Limited to moderate temperature range | Common in consumer RF connectors |
| PBT | Automotive/commercial connectors | Injection molded | Good dimensional stability, cost-effective | Less suitable for high-frequency designs | Often seen in automotive parts |
| PEEK | High temperature, chemical-resistant designs | Machined or injection molded | High strength, chemical and heat resistance | More expensive than PBT | Used for rugged and medical connectors |
| LCP | Compact connectors and multi-ports | Injection molded | High-frequency performance, thin-wall capability | Higher cost vs. commodity plastics | Great for miniaturization |
| Copolymer of Styrene | Cost-effective insulator for general use | Injection molded | Economical, low weight | Lower thermal stability | Lightweight and easy to mold |
| Nylon | General purpose insulator | Injection molded | Tough and impact-resistant | Absorbs moisture, can swell | Readily available, cost-efficient |
| PA | General purpose molded parts | Injection molded | Versatile, cost effective | Lower strength vs. PA66/PA9T | Found in standard molded connectors |
| PA66 | High-temp, stronger nylon alternative | Injection molded | Stronger than PA, more heat-resistant | More expensive than PA | Great for automotive/industrial use |
| PA9T | High-temp, chemical-resistant nylon | Injection molded | Excellent chemical resistance | Costlier than PA66 | Preferred for harsh environments |
| Glass | Specialty HV connectors | Molded, sintered or pressed | Rigid, high dielectric strength | Brittle, prone to cracking | Used in very high-voltage applications |
| Phenolic | Older connectors, legacy parts | Molded phenolic resin | Excellent electrical insulation | Outdated material for most modern designs | Found in vintage connectors |
| Polypropylene | Consumer and low-cost connectors | Injection molded | Lightweight, inexpensive | Lower heat resistance | Widely available commodity plastic |
| Polystyrene | Low-loss, precision RF connectors | Molded or machined | Excellent low-loss electrical properties | Can deform under high heat | Excellent for precision RF designs |
| PPO | Stable engineering thermoplastic | Injection molded | Good dimensional stability | Less common than PTFE or PBT | Good for high-reliability connectors |
| TPX | Microwave connectors (very low loss) | Machined into precision parts | Lowest dielectric loss of all plastics | Expensive specialty plastic | Excellent for ultra-high-frequency use |
| Ultem 1000 | High-strength, high-heat applications | Machined or molded | High strength, high temperature | Premium material cost | Best for aerospace, medical |
| Ultem (Natural) | Transparent natural version of Ultem | Machined or molded | Optical clarity, similar to Ultem 1000 | Premium material cost | Offers visual transparency for QC |
Body & Contact Materials
The connector body and contact pins form the structural and electrical backbone of an RF connector. Their material selection impacts conductivity, corrosion resistance, weight and mechanical robustness. Choosing the right metal ensures long-lasting reliability and stable RF performance.
| Material | Typical Uses | How It's Processed | Key Characteristics & Benefits | Considerations | Noteworthy Attributes |
| Beryllium Copper | Connector bodies (non-magnetic), center contacts, spring fingers | Machined, heat-treated for strength, then plated | High strength, excellent conductivity, non-magnetic | Higher cost, requires careful handling (toxic dust when machining) | Go-to material for non-magnetic connectors |
| Brass | Most common connector bodies, some contacts | Machined easily, can be cold-formed or plated directly | Good balance of conductivity, machinability, and cost | Softer metal, needs plating to avoid corrosion | Most widely used connector body material |
| Copper | High-conductivity custom contacts | Machined and plated for max conductivity | Highest conductivity, excellent for low-loss applications | Oxidizes quickly, requires plating | Ideal for high-power RF due to low resistivity |
| Copper Nickel Alloy | Specialty connectors needing strength + corrosion resistance | Machined or forged depending on strength needs | Great strength and corrosion resistance | More expensive than brass | Often used in aerospace/military parts |
| Phosphor Bronze | Stamped components, certain bodies and contacts | Typically stamped/formed but can be machined | Good spring properties, good wear resistance | Less common for fully machined parts | Excellent for spring contacts and EMI fingers |
| Stainless Steel | High durability body components for harsh environments | Machined with slower feeds due to hardness | Corrosion-resistant, excellent mechanical performance | Harder to machine, higher cost | Preferred for harsh-environment connectors |
| Zamac | Die-cast components for lightweight housings | Die-cast into net shapes, then machined as needed | Good dimensional stability, lightweight | Not as durable as machined metals | Zinc-based alloy with aluminum, magnesium, copper |
| Zinc Diecast | Cost-effective body components for commercial-grade connectors | Die-cast, trimmed, and drilled | Very economical, quick to produce | Lower mechanical strength vs. machined metals | Best for high-volume, low-cost applications |
| Nickel | Occasionally as bulk material in special connectors | Machined or electroformed depending on part | Good hardness and wear resistance | Prone to oxidation if not plated | Can also serve as underlayer for other platings |
Plating & Finishes
Plating adds a protective and functional layer to the base material, improving conductivity, corrosion resistance and wear performance. Different platings are chosen based on the environment, expected mating cycles and cost-performance balance.
| Plating / Finish | Typical Uses | How It's Processed | Key Characteristics & Benefits | Considerations | Noteworthy Attributes |
| Gold | Premium body & contact plating for corrosion resistance and conductivity | Electroplated in thin layers for durability | Best conductivity, corrosion-proof | Most expensive plating | Industry standard for high-performance RF |
| Gold/Nickel | Cost-efficient gold plating with nickel barrier layer | Nickel barrier applied first, then gold plated | Barrier layer prevents diffusion, good reliability | Slightly higher cost than tin-only | Good compromise of cost and performance |
| Gold/Passivated | Gold over passivated stainless steel | Passivation then selective gold plating | Corrosion protection with gold performance | More steps = higher cost | Great for mixed-material connectors |
| Gold/White Bronze | Gold over tri-metal/white bronze for PIM-sensitive designs | White bronze or tri-metal base layer before gold | Excellent for low PIM connectors | Special process, adds cost | Preferred for PIM-sensitive telecom |
| Nickel | Body plating for corrosion protection | Electroplated for uniform finish | Hard, durable, protective | Magnetic (unless electroless nickel) | Most common general-purpose finish |
| Nickel/Gold | Layered finish for mixed cost/performance applications | Nickel then gold layered electroplating | Excellent corrosion protection, good conductivity | More expensive than single layer finishes | Used in military and aerospace |
| Nickel/Matte Tin | Environmental durability + solderable finish | Nickel underlayer then matte tin | High durability, solderable | Tin whiskers possible if not controlled | Good for automotive/high vibration |
| Nickel/Tin | Cost-effective protection + solderability | Nickel underlayer then tin plating | Durable and cost-effective | Slightly higher resistance than gold | Great for cost-controlled designs |
| Tin | Commercial-grade connectors, terminals | Hot dip or electroplated tin layer | Good solderability, low cost | Lower corrosion resistance than gold/nickel | Used in consumer-grade and telecom |
| Bright Tin | Consumer-grade connectors, terminals | Electroplated with bright appearance | Bright appearance, solderable | May oxidize, cosmetic concern | Bright finish ideal for commercial use |
| Matte Tin | Tin finish with matte appearance, good for soldering | Electroplated matte finish | Excellent solderability, matte look | Matte can be less visually appealing | Preferred for hand soldering applications |
| Silver | Contacts in low-loss connectors | Electroplated silver layer | Lowest resistivity of all platings | Can tarnish over time | Used in precision metrology connectors |
| White Bronze (Albaloy) | Non-magnetic alternative to nickel plating | Electroplated tri-metal coating | Non-magnetic, high corrosion resistance | More expensive than nickel | RoHS-compliant, nickel-free option |
| Tin/Nickel EE | Extreme environment plating (700+ hr salt spray) | Special composite electroplating process | Exceptional salt spray endurance | Specialty use only | Meets extreme environment specs |
| Black | Aesthetic finish, some EMI shielding uses | Applied as final finish over plating or base | Visual differentiation, some environmental benefit | Purely aesthetic in most cases | Used in special black-finish assemblies |
| Passivated | Surface treatment for stainless steel | Chemical treatment, no added layer | Maintains corrosion resistance of stainless | No change in appearance, just corrosion protection | Standard finish for stainless steel |
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