SMA vs RP-SMA Connectors: Differences and How to Identify Them

1. What is the difference between SMA and RP-SMA?

RP means reverse polarity. In this context it describes the center-contact arrangement, not a reversed electrical signal or a left-hand thread. Amphenol explains that RP-SMA reverses the center-contact gender while retaining the same threaded interface.

For a plug body with internal coupling threads, standard SMA has a center pin and RP-SMA has a center socket. For a jack body with external threads, standard SMA has a socket and RP-SMA has a pin. Record the full interface designation rather than saying only male or female.

Technical reference: Amphenol RF: SMA and reverse-polarity distinction ↗

2. SMA male vs female: a four-way identification table

Look straight at the mating face with the equipment disconnected. Identify whether the coupling nut has internal threads or the mating body has external threads, then inspect the center contact. The combination identifies the four conventional forms below.

Technical reference: AMETEK guide: connector gender and standard/reverse polarity ↗

3. Can SMA and RP-SMA connectors connect together?

Specify a complementary plug and jack within the intended interface family. A standard SMA plug pairs with a standard SMA jack; an RP-SMA plug pairs with an RP-SMA jack. Cross-pairing can leave two sockets without a center connection or bring two pins together.

Do not force a connection or use the ability to engage threads as the acceptance check. If the equipment and cable have different interfaces, identify both ends completely and review a purpose-built adapter or replacement assembly with the supplier.

For purchasing records, store a clear face-on image with the confirmed equipment port part number. This makes repeat orders easier to check and helps avoid a listing that abbreviates the connector description inconsistently.

4. Choose the RF connector beyond its mating face

Once the interface is identified, review the cable termination and mounting. A cable connector, PCB connector and bulkhead connector may use the same mating family while requiring different installation details. Include straight or right-angle orientation and the available space for assembly.

The connector must also match the relevant operating requirements. Ask for the individual part drawing and datasheet, including the intended cable types and applicable electrical and environmental ratings. A general family description is not a substitute for the proposed part specification.

For an outdoor antenna connection, describe the sealing arrangement and installation conditions. Do not infer waterproofing from an SMA or RP-SMA label. Confirm any required sealing performance for the specific connector and completed installation.

Technical reference: Amphenol RF: RP-SMA configurations and part-dependent specifications ↗

5. Apply the checks to SMA cable assemblies

For an SMA to SMA cable assembly, identify end A and end B independently. A request for a male-to-female extension still needs polarity, cable type, length and mounting details. Include the approved drawing reference in the inquiry.

For an SMA to IPEX antenna cable, check the SMA end with the table above and identify the exact miniature connector at the other end. The SMA polarity check does not establish which board connector is required.

When the cable route changes, review the finished length, bend space and strain relief as well as the connector. For a longer antenna run, add a loss target so connector selection and coaxial cable selection can be reviewed together.

6. What to send when ordering RF connectors

A complete description helps a supplier resolve the interface question before preparing the quote. Separate mandatory part requirements from alternatives you are willing to review. If you need an exact replacement, provide the original part number and drawing revision.

ANNXIN supplies RF connectors and supports custom RF cable assembly inquiries. Share the interface and installation brief below for review; the proposed part, availability and commercial terms must be confirmed for your order.

• Family and polarity: SMA or RP-SMA, with plug/jack designation.
• Face-on photo plus equipment port drawing or part number.
• Mounting: cable, bulkhead or PCB; straight or right-angle.
• Cable termination: actual cable part number and construction, if applicable.
• Operating requirements, quantity, destination and documentation needs.