What are RF connectors?
RF connectors are connectors used to make electrical connections for signal transmission in radio frequency applications. These connectors are used in a wide variety of applications ranging from 0 to 18 GHz and above.
All types of RF connectors have one male connector and one female connector. Male connectors are often called plugs, and female connectors are called jacks. The center pin and outer grounding with a locking mechanism provide it with a strong and reliable connection.
The selection of an RF connector depends on the specifications, like frequency range, performance, size, and shape of each connector type. Here are the most commonly used RF connectors:
BNC
BNC is one of the commonly used connectors for low-frequency RF applications. It is an easy-to-use connector with a 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 parts of the SHF range. Smaller size and reliable performance make SMA connectors a favorite choice for RF engineers.
SMA connectors are one of the best-performing connectors in terms of impedance matching. The most common type is a 3.5 mm connector.
Operating frequency: 0 to 18 GHz
Applications: GSM, CDMA, radio communication boards, RF power amplifiers, RF isolators, 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 a customized shape for a variety of applications. It’s a simple design suitable for easy connection and disconnection 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 equipment, base stations, low-power UHF communication systems, and radio applications.
N-type
N-type is a medium-sized RF connector suitable for durable applications. It offers a stable performance up to 11 GHz. N-type has a thread-locking mechanism that provides a strong and reliable connection.
There are waterproof 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 equipment, base stations, 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-precision measurement solutions.
Operating frequency: 0 to 40 GHz
Applications: High-precision tests 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 connectors used for low-frequency applications such as amateur radio and marine communication systems. It has a strong structure, is easy to assemble with coaxial cable, and is 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 the 100 MHz range.
Operating frequency: Below 100 MHz
Applications: amateur radio and shortwave radio applications.
Summary of Common RF Connectors
| Connector Type | Impedance | Typical Frequency Range | Common Applications |
| BNC (50/75 Ω) | 50 Ω / 75 Ω | Up to ~4 GHz (75 Ω: ~2 GHz) | Test instruments, analog video, amateur radio |
| TNC | 50 Ω | DC – 11 GHz | Mobile RF setups, telecom, antenna connections |
| SMB | 50 Ω / 75 Ω | DC – 4 GHz | Base stations, GPS modules, compact RF modules |
| N-Type | 50 Ω / 75 Ω | DC – 11 GHz (up to 18 GHz precision) | Telecom, broadcast, antenna systems |
| 7/16 DIN | 50 Ω | Up to ~7.5 GHz | Cellular base stations, high-power RF lines |
| 4.3‑10 | 50 Ω | DC – 6 GHz (some up to 12 GHz) | 4G/5G infrastructure, macro cells |
| SMA | 50 Ω | DC – 18 GHz (some up to 26.5 GHz) | Microwave radios, RF boards, GPS/Wi‑Fi modules |
| SMC | 50 Ω | Up to ~10 GHz | Wireless and instrumentation links |
| MCX / MMCX | 50 Ω | DC – 6 GHz | Compact RF modules, IoT, embedded radios |
| 3.5 mm | 50 Ω | DC – 26.5 GHz | High-precision test and measurement |
| 2.92 mm (K‑type) | 50 Ω | DC – 40 GHz | Precision microwave, radar, aerospace |
| 2.4 mm | 50 Ω | DC – 50 GHz | mmWave systems, scientific and industrial instruments |
| 1.85 mm (V‑type) | 50 Ω | DC – 67 GHz | Advanced test equipment, high-end communications |
| 1.0 mm (W‑type) | 50 Ω | DC – 110 GHz | Ultra-high-frequency (UHF), metrology, mmWave labs |
| U.FL | 50 Ω | DC – 6 GHz | Internal RF links (Wi‑Fi, GPS) in laptops, modules |
Conclusion
RF connectors are available in any size, shape, and frequency range to fit various applications. It has to be selected according to the specification required for particular applications. RF connector adaptors are used to connect two different standards.
Reference:
Amphenol 2.92 mm connectors
Pasternack 1.85 mm high-frequency RF connector
