RF (Radio Frequency) signals operate at very high frequencies, typically in the MHz to GHz range. At these frequencies, signal integrity is highly sensitive to impedance mismatches, losses, and electromagnetic interference (EMI).
RF connectors are specially engineered to ensure optimal signal transmission by:
• Maintaining consistent impedance (usually 50 or 75 ohms), preventing signal reflection and standing waves.
• Minimising insertion loss, ensuring that signal strength is preserved along the transmission path.
• Providing excellent shielding, protecting sensitive signals from external EMI.
• Supporting high-frequency transmission, with minimal degradation or distortion.
Using non-RF connectors for RF signals often leads to signal distortion, higher return loss, and unreliable system performance. For this reason, it is essential to use purpose-built RF connectors and cables in all RF systems.
RF Connector Selection
RF connectors play a critical role in ensuring reliable signal transmission across high-frequency applications. Selecting the right connector is essential to maintain signal integrity, reduce losses, and ensure compatibility with system requirements.
This overview provides details on commonly used RF connectors, their frequency capabilities, and typical application scenarios — helping engineers and system designers choose the most suitable option for their design.
Connector Selection by Era, Frequency, and Application
| Connector | Typical Frequency Range | Key Features | Common Applications |
| UHF (1930s) | Up to ~500 MHz | Early RF connector, non-constant impedance (~30–35 Ω) | CB radios, amateur radio, legacy systems |
| BNC (1940s–50s) | Up to ~4 GHz (50 Ω), ~2 GHz (75 Ω) | Bayonet quick-lock, easy handling | Test equipment, video systems, lab setups |
| N-Type (1950s–60s) | ~11–18 GHz(50 Ω) | Constant impedance, robust and weatherproof | Base stations, radar, microwave, outdoor RF |
| TNC (1960s) | Up to ~11 GHz(50 Ω) | Threaded version of BNC, vibration resistant | RF instrumentation, mobile radio systems |
| SMA (1960s–present) | ~18–26.5 GHz(50 Ω) | Compact, high-performance threaded design | GPS, 5G, aerospace, IoT modules, RF test gear |
| MMCX (1980s) | Up to ~6 GHz(50 Ω) | Ultra-compact, snap-on design | GPS devices, medical electronics, wearables |
| FME (1980s–90s) | Up to ~2 GHz(50 Ω) | Slim profile, screw-on connector | Automotive antennas, cellular routers, modems |
| QMA (2000s) | Up to ~6 GHz(50 Ω) | Quick-lock alternative to SMA, rotation-free installation | Telecom infrastructure, industrial RF systems |
| 2.92mm / K-type+ (Modern) | Up to 110 GHz(50 Ω) | Precision connectors for mmWave and high-speed systems | RF/microwave testing, 5G/mmWave, radar, aerospace |
When selecting an RF connector, consider the following:
Frequency Requirements
• Match the connector’s frequency rating to your application’s needs (e.g. 2.4 GHz Wi-Fi vs. 28 GHz mmWave).
Impedance
• Most systems require 50 Ω impedance. 75 Ω connectors are used in specific video and broadcast applications.
Environmental Conditions
• Use weatherproof connectors (e.g. N-Type) for outdoor or rugged environments.
Size Constraints
• Choose compact connectors (e.g. MMCX) for space-limited designs or embedded modules.
Coupling Mechanism
• Select based on handling and vibration tolerance:
• Threaded: SMA, TNC (secure but slower to connect)
• Snap-on: MMCX, SMB (quick, compact)
• Bayonet/Quick-lock: BNC, QMA (fast and reliable)
Summary
RF connectors are critical components in ensuring high-performance signal transmission across a wide range of applications, from traditional radio systems to advanced 5G and mmWave technologies. Selecting the appropriate connector type — based on frequency range, impedance, size, and coupling method — is essential for achieving optimal performance and long-term reliability.
Siretta offers a comprehensive range of RF connectors, adaptors, cable assemblies, and antenna solutions, designed to meet both legacy and next-generation RF requirements. Whether you’re developing systems for industrial IoT, telecommunications, automotive, or aerospace applications, Siretta combines technical expertise with a broad product offering to support all your connectivity needs.
