RF coaxial connectors are mainly used for transmitting radio frequency signals across a wide frequency range. They are widely applied in radar, communications, aerospace equipment, and instrumentation systems. There are many types of RF connectors, classified in different ways. This article provides a detailed introduction to the MCX connector.
1. Connector Classification
The basic structure of an RF coaxial connector includes:
Center conductor (male or female contact)
Insulator
Outer conductor/contact (serves as shielding and grounding, similar to the outer layer of a coaxial cable)
RF coaxial connectors can be classified by size as follows:
By Size
Standard Types: UHF, N, 7/16, 7 mm
Miniature Types: BNC, TNC
Subminiature Types: SMA, SMB, SMC, MCX, BMA, SAA, 3.5 mm
Micro Types: SSMA, SSMB, MMCX, 2.4 mm, K (2.92 mm), 1.85 mm, 1 mm
From this classification, MCX belongs to the subminiature push-on RF connector category, widely used in transportation, communication, networking, IT, medical, and consumer electronics fields.
2. MCX Connector Overview
For applications requiring smaller alternatives to SMA connectors, subminiature options include SMB, MCX, and MMCX connectors. Compared to high-frequency connectors such as 2.4 mm, 1.85 mm, and 1 mm types-which are more expensive and require threaded coupling-the snap-on design of MCX connectors offers significant convenience.
MCX connectors are available in both 50 Ω and 75 Ω impedance, with a typical operating frequency up to 6 GHz.
Example:
75 Ω MCX straight plug connector, crimp/solder type, suitable for coaxial cables such as RG179 and RG187
3. Technical Characteristics
Developed in the 1980s as a more compact version of SMB
Approximately 30% smaller than SMB connectors
Outer diameter: 3.6 mm
Compliant with IEC 61169-36 and CECC 22220 standards
RF leakage: typically >70 dB (DC–1 GHz)
Dielectric withstand voltage: up to 1000 V
Mating cycles: ≥500 cycles
Operating temperature range: –65°C to +165°C
4. Advantages of MCX Connectors
4.1 Fast Installation
The push-on coupling mechanism allows quick connection and disconnection, significantly reducing installation time.
4.2 Easy Maintenance
Faulty components can be quickly replaced without complex procedures.
4.3 Easy Upgrading
Components can be easily upgraded as technology evolves, improving system performance.
4.4 Design Flexibility
MCX connectors provide engineers with greater flexibility in product design, system integration, and modular assembly.
5. Applications of MCX Connectors
5.1 GPS and RF Modules
Connecting GPS antennas to receivers
Used in USB DVB-T tuners
5.2 Consumer Electronics
Wireless modules in computer systems
Compact RF signal connections in portable devices
5.3 Testing and Measurement
Entry-level and cost-effective equipment such as
Software-defined oscilloscopes
RF testing instruments
5.4 PCB Signal Routing
MCX connectors are often used to route signals between different sections of a PCB or across multiple PCBs, especially when:
Planar transmission lines have excessive loss
Systems are sensitive to interference
5.5 RF Accessories
Typical MCX-based components include:
Adapters
Coaxial cable assemblies
DC blocks
Frequency synthesizers
Terminators
Example:
Built-in DC block, 50 Ω MCX male to MCX female, frequency range 10 MHz – 6 GHz, rated voltage 50 V, brass body
6. Material and Limitations
MCX connectors are compact, which limits their voltage and power handling capabilities:
Typical working voltage: 170 Vrms
Dielectric withstand voltage: 500 Vrms
Materials:
Brass (body and contacts)
PTFE (Teflon) insulator
Gold or nickel plating for corrosion resistance
7. Conclusion
MCX connectors offer an excellent balance of compact size, reliable RF performance, and ease of use. Their push-on design, cost-effectiveness, and versatility make them widely used in communication systems, consumer electronics, automotive applications, and RF testing equipment.
As electronic devices continue to become smaller and more integrated, MCX connectors remain a practical and efficient solution for high-frequency signal transmission.