What is an MCX Connector?

It is often useful to have coaxial connectorized components available that are smaller than even SMA connectorized components. When this is the case, there are a few options. Namely, subminiature version B (SMB), micro coaxial connectors (MCX), micro-miniature coaxial connectors (MMCX), and other much higher frequency connectors. Since the 2.4 mm, 1.85 mm, 1.35 mm, and 1 mm series tend to be on the more expensive side and still require torquing of a threaded nut, the snap-on interface of a MCX connector is advantageous. An example of this is an MCX Attenuator, which can have either a 50 Ohm or 75 Ohm interface and are generally capable of operating to 6 GHz.

MCX connectors  were developed in the 1980s as a more compact version of the SMB. MCX connectors are 30% smaller in diameter than SMB connectors, at 3.6 millimeters (1.4 in) in diameter. MCX connectors are based on the IEC 61169-36 and CECC 22220 standards. RF leakage ratings for MCX connectors are generally over 70 dB from DC to 1 GHz. Dielectric withstand voltage for MCX connectors is rated to 1000 Volts. Typical MCX connectors can withstand 500 or more mating cycles with the snap-on connector feature. MCX connectors operate over a wide temperature range from -65 °C to +165 ℃.

A common application for MCX connectors is to connect GPS antennas to GPS receivers and for USB DVB-T tuners. More recent common uses of MCX connectors include computer tower wireless connectivity and use with hobby-grade/inexpensive electric test equipment, such as software-defined oscilloscopes. MCX connectors are also often used to internally route signals to different sections of a PCB circuit or across PCBs where planar transmission lines and waveguides would be too lossy or prone to interference compared to a coaxial transmission line environment.

Hence, it is beneficial to have MCX connectorized components that are readily compatible with the new use cases of MCX connectors. This would include MCX adapters, coaxial cable assemblies, connectors, DC blocks, synthesizers, terminations, etc. It is important to note that the MCX connector is a compact connector and presents limited voltage and power handling. Typical operating voltages for MCX connectors are 170 Vrms with dielectric withstand voltages of 500 Vrms. MCX connectors are often made with brass contacts and bodies, as well as PTFE insulation. Gold over nickel coatings are often used to coat the brass and provide superior corrosion resistance.