SMA male and female connectors are identified by checking the threaded body and center contact together. A standard SMA male has internal threads and a center pin, while a standard SMA female has external threads and a center socket. RP-SMA keeps the same threaded interface but reverses the center contact, so both features need to be confirmed before ordering a connector, adapter, or cable assembly.
How to Identify SMA Male and Female Connectors
SMA basic definition: 50Ω precision threaded RF connector
SMA is a type of 50Ω threaded RF connector. Due to its miniaturized structure, excellent electrical performance, and reusable mechanical characteristics, it is widely used in microwave communication, test instruments, RF modules, antenna systems, GNSS/GPS, IoT terminals, and other fields.
In this article, standard SMA refers to the interface in which the male connector has internal threads and a center pin, while the female connector has external threads and a center socket. These two interfaces form the standard SMA mating pair.
What Does RP-SMA Change
RP-SMA, or Reverse Polarity SMA, retains the same connector body dimensions and threaded interface as standard SMA, but reverses the center pin and center socket. In common SMA catalog naming, the plug interface normally has an internal-thread coupling body, while the jack interface has an external-thread body.
This creates four different interfaces: SMA male, SMA female, RP-SMA male, and RP-SMA female. A connector cannot be identified from the center pin alone because both an SMA male and an RP-SMA female have a center pin.
How to Identify the Four SMA Interfaces
To learn more about the broader differences between the two connector families, please refer to our article Differences Between SMA and RP SMA Explained.
Standard structure of SMA connector
Standard SMA connectors come in two types: Male and Female.
- SMA male connector: The male or plug interface has a coupling nut with internal threads and a protruding center pin. It mates with a standard SMA female connector.
- SMA female connector: The female or jack interface has external threads and a recessed center socket. The socket receives the center pin of the SMA male connector.
Reverse Polarity SMA
RP-SMA uses the same male and female threaded bodies as standard SMA, while reversing the center contacts. Reverse polarity refers to the center contact configuration, not a change in thread direction.
- RP-SMA male connector: The male or plug body has internal threads, but its center contact is a socket instead of a pin.
- RP-SMA female connector: The female or jack body has external threads, but its center contact is a pin instead of a socket.
Four SMA Interface Types at a Glance
Use the threaded body to identify the connector gender, then check the center contact to determine whether it is standard SMA or RP-SMA.
| Connector Type | Threaded Body | Center Contact | Matching Interface |
|---|---|---|---|
| SMA male | Internal threads | Center pin | SMA female |
| SMA female | External threads | Center socket | SMA male |
| RP-SMA male | Internal threads | Center socket | RP-SMA female |
| RP-SMA female | External threads | Center pin | RP-SMA male |
Which SMA Interfaces Can Mate
After identifying both connectors, compare the thread position and the center contact. Matching threads do not automatically mean that the center contacts can form an RF connection. The intended mating pairs are:
- A standard SMA male connector mates with a standard SMA female connector.
- An RP-SMA male connector mates with an RP-SMA female connector.
An SMA male and an RP-SMA female have compatible internal and external threads, but both interfaces contain center pins. Tightening them together can press the two pins against each other and may damage the center contacts. The connector bodies may engage while the center conductors remain disconnected, leaving the RF path open.
Where SMA and RP-SMA Connectors Are Commonly Found
Common Applications of SMA
Standard SMA connectors are commonly found on test instruments, RF modules, GNSS/GPS equipment, antenna systems, small base stations, distributed antenna systems, industrial equipment, and RF cable assemblies. The equipment port and connector drawing determine whether a male or female interface is needed.
The connector interface is one part of the selection. Cable type, operating frequency, straight or right angle orientation, mounting method, VSWR, insertion loss, and environmental requirements also affect the finished cable assembly.
Common Applications of RP-SMA
RP-SMA connectors are commonly found on WiFi routers, access points, WLAN modules, wireless cameras, drone communication equipment, Bluetooth or Zigbee devices, IoT gateways, and embedded antenna links.
RP-SMA uses the same threaded coupling as standard SMA but reverses the center contact. The equipment category alone does not confirm the interface, so the mating face or product drawing still needs to be checked.
FAQs
Conclusion
SMA male and female connectors are identified by checking the threaded body and center contact together. A standard SMA male has internal threads and a center pin, while a standard SMA female has external threads and a center socket. RP-SMA retains the same threaded bodies but reverses the center contacts. Before confirming a connector or cable assembly, review both mating interfaces, cable specifications, orientation, mounting method, operating frequency, and test requirements. If the connector type is uncertain, you can share the equipment model, drawing, or a clear front view with the Bafitop team for interface review.