SMA RF Connectors Guide: Types, Structure, and Uses Explained
Summary
SMA (Subminiature Type A) connectors are high-performance miniature connectors for RF/microwave applications, supporting a wide frequency range with exceptional durability. They come in stainless steel or brass, depending on the application. With a 50 Ω impedance and a threaded coupling, they ensure secure connections. For frequencies above 18 GHz, we also offer high-frequency cables—contact us for details.
SMA RF Connectors by Type
In-Stock Coaxial Cables with SMA RF Connectors
SMABJ-to-MHF I Micro-Coaxial Cables
SMABJ-to-U.FL Micro Coaxial Cables
Micro Coaxial Cables
Semi-Flexible
Semi-Rigid
Trivia: Compatible Cable Types
- MIL Standard Cables: Also called Mil-Spec, these cables meet strict US military standards for performance and durability. Often starting with "RG" (Radio Guide), they are essential in high-demand areas like defense, aerospace, and telecommunications.
- Micro Coaxial Cables: These ultra-thin cables are designed to connect to miniature RF connectors like U.FL. They ensure signal integrity in space-constrained electronic devices such as smartphones, laptops, and medical equipment.
- Semi-Flexible Coaxial Cables: With moderate flexibility, these cables can bend and hold their shape while offering strong shielding and low signal loss, making them ideal for precise routing in telecommunications, test equipment, and internal electronics.
- Semi-Rigid Coaxial Cables: Made from a seamless metal tube, these cables provide superior shielding and minimal signal loss. Their rigid design ensures stable performance in critical applications like military systems, high-frequency instruments, aerospace, and microwave assemblies.
SMA RF Connector Features
Compact Size
The small form factor allows for high-density mounting in tight spaces, making it ideal for wiring within equipment and connecting subassemblies and devices.
High-Frequency
Our product lineup supports high-frequency applications, ranging from DC to 18 GHz, with test cables available for use up to 26.5 GHz.
Stability
The threaded coupling is recommended over the Quick-Connect type for a more secure connection.
SMA RF Connector Applications
Our SMA RF connectors are engineered for demanding high-frequency applications. They provide reliable 50 Ω performance, ideal for mobile communication base stations needing robust signal integrity and compact communication devices where space is limited. They ensure accuracy in precision measuring instruments and enable connectivity for wireless LAN and GPS systems. Known for durability and stable connections up to 18 GHz.
SMA RF Connectors: Standards & Technical Specifications
Compatible Standards
MIL-C-39012 (U.S. Military Standard), IEC 60169-15 (Global), JEITA RC-5234 (Japan Electronics Standard).
Nominal Impedance
Connector impedance is standardized at 50 Ω, ideal for efficient RF signal transmission.
Coupling Method (Connection)
Uses a threaded coupling mechanism (1/4-36UNS-2A, 2B threads), ensuring a secure and stable connection.
Working Voltage (Rated Voltage)
Designed to safely handle voltages up to AC 500V during regular operation.
Maximum Withstanding Voltage (Dielectric Withstanding Voltage)
Semi-rigid Cable :
- ・ 0.085 in: AC 750 V (1 min)
- ・ 0.141 in: AC 1,000 V (1 min)
Flexible Cable :
- ・ RG-316/U, RG-188A/U: AC 750 V (1 min)
- ・ RG-142B/U: AC 1,000 V (1 min)
Insulation Resistance
Provides high insulation resistance (minimum 5,000M Ω) at DC 500V, preventing electrical leakage and ensuring safety.
Mass Production
Once satisfied with test results and pricing, you can proceed with placing a mass-production order.
Contact Resistance
Ensures minimal electrical resistance (max. 4m Ω at DC 0.1A), providing stable signal quality and reliable connection.
Frequency Range
Supports a wide frequency range from 0 to 12,000MHz, suitable for various high-frequency applications.
Voltage Standing Wave Ratio (V.S.W.R.)
Semi-rigid Cable:
- ・ 0.085 in: 1.07 + 0.015fG
- ・ 0.141 in: 1.05 + 0.01fG (fG = GHz)
Semi-Flexible Cable Available: Please inquire.
Materials
Made of durable stainless steel and brass, providing strength and reliability under various conditions.
Surface Treatments
Surface options include passivation, nickel plating, and gold plating, enhancing corrosion resistance and conductivity.
Wiring Methods
Connection methods available are soldering, crimping, and tightening, allowing flexible and secure installation.
Note: The figures provided are typical values. For further details, please contact us.
SMA RF Connector FAQs
QWhat is reverse polarity?
QWhat is reverse polarity?
Standard SMA plugs have male contacts, jacks female. Reverse Polarity (RP-SMA) swaps this: plugs have female contacts, jacks male. RP-SMA is often used in radio comms equipment outside Japan.
QAre frequencies above 18 GHz supported?
QAre frequencies above 18 GHz supported?
Standard SMA connectors support up to 18 GHz. Higher frequencies require specialized handling, so standalone connector performance isn't guaranteed. Cable assemblies for up to 26.5 GHz are available.
QIs there a smaller compatible connector?
QIs there a smaller compatible connector?
Yes, 3.5 mm and 2.92 mm (K) connectors are smaller than SMA but remain compatible. They also support frequencies beyond the standard 18 GHz SMA limit. We offer these connectors and test cables.
QWhy do SMA, 3.5 mm, and 2.92 mm K connectors require conversion adapters if they are compatible?
QWhy do SMA, 3.5 mm, and 2.92 mm K connectors require conversion adapters if they are compatible?
Although SMA, 3.5 mm, and 2.92 mm connectors can physically mate, using between-series adaptors guarantees optimal performance, vital for precise measurements in labs and research settings.
QIs there a quicker way to connect and disconnect threaded connectors?
QIs there a quicker way to connect and disconnect threaded connectors?
Yes, quick-connect adaptors provide fast, tool-free connection/disconnection for threaded types like SMA and N, boosting efficiency in test and measurement environments where speed is valuable.
QAre waterproof SMA connectors available?
QAre waterproof SMA connectors available?
Yes, waterproof SMA connectors with various IP ratings are available. Waterproofing methods include sealing the mating interface, cable attachment points, and using O-rings for ingress protection.
QCan SMA connectors be used for both RF and DC applications?
QCan SMA connectors be used for both RF and DC applications?
While designed for RF, SMA connectors can handle low-power DC. However, for high-power DC applications, dedicated DC connectors are recommended for safety and optimal performance reliability.
QHow do I properly clean SMA connectors?
QHow do I properly clean SMA connectors?
Clean SMA connectors using a soft brush, lint-free cloth, and isopropyl alcohol or mild contact cleaner. Avoid abrasives. Regular cleaning maintains performance, especially in harsh environments.
QWhat is the best material for SMA connectors?
QWhat is the best material for SMA connectors?
Common SMA bodies are brass or stainless steel. Inner contacts are typically gold-plated for low loss conductivity. Outer shells use gold or nickel plating for corrosion resistance and durability.
QCan SMA connectors be used in high-vibration environments?
QCan SMA connectors be used in high-vibration environments?
SMAs work in moderate vibration. For high-vibration areas like automotive or aerospace, consider more rugged TNC or N-type connectors with superior locking mechanisms for reliable connections.
QHow can I order SMA connectors, and what support do you offer?
QHow can I order SMA connectors, and what support do you offer?
Ordering is simple—you can purchase our SMA connectors directly on our website or contact our sales team for assistance. We also provide full technical support, including datasheets, CAD models, and application notes, to help you pick the perfect connector for your project.