SMA vs RP-SMA : What is the differences ？
Commonly, we made mistakes when buying antennas on confusing SMA Connector and RP SMA (Reverse Polarity SMA) Connector, they looks quite similar but not compatible with each other.
Quick Comparison
| Connector Type | Outer Thread | Center Contact |
|---|---|---|
| SMA Male | Inside Thread | Pin |
| SMA Female | Outside Thread | Socket |
| RP-SMA Male | Inside Thread | Socket |
| RP-SMA Female | Outside Thread | Pin |
Note: The key difference is the center conductor.
SMA Connector
SMA Male Connector
- Internal Thread
- Center Pin
Typical used for :
- LoRa Modules
- 433MHz Antennas
- 868MHz Antennas
- 915MHz Antennas
- GPS Antennas
- Industrial RF Devices
SMA Female Connector
- External Thread
- Center Socket
Commonly used on:
- Gateways
- Routers
- RF Modules
- Wirelss Equipments
RP SMA Connector
RP=Reverse Polarity, which means that the thread is the same but the center conductor is reversed.
RP SMA Male Connector
- Internal Thread
- Center Socket
RP SMA Female Connector
- External Thread
- Center Pin
These two reverse connectors is commonly found on : WIFI Routers, WIFI Adapters and Consumer Networking Equipments
Compatible Table
| Device Connector | Antenna Connector Needed |
|---|---|
| SMA Female | SMA Male |
| SMA Male | SMA Female |
| RP-SMA Female | RP-SMA Male |
| RP-SMA Male | RP-SMA Female |
Typical Applications
SMA Connector
Most RF and IoT applications:
- LoRa
- 433MHz ISM
- 868MHz ISM
- 915MHz ISM
- GPS
- LTE
- 5G
- Industrial wireless
RP SMA Connector
Mostly consumer WiFi products:
- WiFi routers
- WiFi cards
- WiFi extenders
- Access points
FAQs
Can SMA and RP-SMA connect together?
No. Although the threads may appear to fit, the center contacts are different and they are not designed to mate correctly.
Why does WiFi equipment use RP-SMA?
Historically, RP-SMA was adopted to discourage the use of non-certified antennas on consumer WiFi devices.
Which connector is used on LoRa antennas?
Most LoRa antennas use standard SMA connectors, although some manufacturers offer RP-SMA versions.
How do I know which connector I need?
Check:
- Device datasheet
- Existing antenna
- Connector center pin/hole configuration