Most common RF connectors and its applications

What are RF connectors?

RF connectors are connectors used to make electrical connection for signal transmission in radio frequency applications. These connectors are used in wide variety of applications range from 0 to 18 GHz and above.

All types of RF connector have one male connector and one female connector. Male connectors are often called plug and female connectors as jack. Center pin and outer grounding with locking mechanism provides it a strong and reliable connection.

Selection of an RF connector depends on the specifications like frequency range, performance, size and shape of each connector types. Here are the most commonly used RF connectors:

BNC

BNC is one of the commonly used connectors at low frequency RF applications. It is an easy to use connector with rigid body and locking mechanism. BNC connector has the simplest design among other connectors.

Operating frequency: 0 to 4GHz

Applications: video signals, amateur radio, timing / clock signals and instrumentation.

SMA

SMA connector is one of the most suitable RF connectors at UHF and most part of the SHF range. Smaller size and reliable performance makes SMA connector favorite choice for RF engineers.

SMA connectors are one the best performing connectors in terms of impedance matching. Most common type is 3.5 mm connector.

Operating frequency: 0 to 18 GHz

Applications: GSM, CDMA, radio communication boards, RF power amplifiers, RF isolator, power splitters, directional couplers, Wi-Fi antennas and low power UHF communication systems.

SMB

SMB is another rigid, easy to use RF connector with lower cost and customized shape for variety of application. It’s simple design suitable for an easy connection and disconnecting without any difficult mechanism of locking threads. SMB connector offers better performance at below 4 GHz frequency.

Operating frequency: 0 to 10 GHz

Applications:  Medical equipments, base stations, low power UHF communication systems and radio applications.

N-type

N-type is medium sized RF connectors suitable for durable applications. It offers a stable performance up to 11 GHz. N-type has a thread locking mechanism which provides strong and reliable connection.

There are water proof n-type connectors available for specific applications. Most of the RF test equipment uses N-type as its default connector solution due to its durability and performance. It is a good choice for well matched impedance applications.

Operating frequency: 0 to 12 GHz

Applications:  RF equipments, base stations and low power and high power UHF communication systems, satellite systems and RADAR systems.

2.92 mm connector

2.92 mm connector is yet another RF connector designed to operate in high frequency and microwave test applications. It offers mechanical stability and repeatability for high precising measurement solutions.

Operating frequency: 0 to 40 GHz

Applications: High precision test and measurements, satellite communications, RF test instruments

2.4 mm connector

2.4mm connector is a sub miniature screw-on type 50 Ohm connector option for phase stability applications with low loss. It was developed in 1986, popular for its rigidity compared to SMA connectors with a thicker outer wall.

Operating frequency: 0 to 50 GHz

Applications: RF telecommunication systems, Satellite communication , test and measurement labs, 5G – NR and millimeter wave applications

Other low frequency connectors

PL-259

PL-259 is one of the oldest RF connector used for low frequency applications such as amateur radio and marine communication systems. It has a strong structure, easy to assemble with coaxial cable and still popular among radio enthusiasts.

Operating frequency: Below 200 MHz

Applications:  Mainly in amateur radio applications, shortwave radio, timing signal systems, and low power HF communication systems.

SO-239

SO-239 is yet another low frequency RF connector typically used in applications below 100 MHz range.

Operating frequency: Below 100 MHz

Applications:   amateur radio and shortwave radio applications.

Conclusion

RF connectors are available in many size shape and frequency range to fit wide variety of applications. It has to be selected according to the specification required for particular applications. RF connector adaptors are used to connect between two different standards.