What are Micro-Coax Cables?

What are micro-coaxial cables? What types of connectors do they use? Where are they used?

1 Answer
Can you answer this question?

- everything RF

Nov 5, 2022

Micro-Coaxial cables are coaxial cables with a smaller outer diameter than conventional coax-cables. They usually have an outer diameter of 1 mm or less. Due to the smaller diameter these cables take up less space and are very flexible. These cables typically do not use the conventional coaxial connectors, but micro coax connectors like U.FL Connectors developed by the Hirose Electric Group,  MHF Connectors by I-PEX or AMC connectors by Amphenol.

Micro-coax cables use the standard multilayered coaxial cable structure with a 7-wire stranded type center conductor covered with an insulator/dielectric layer along with an outer conductor and jacket. They usually have an outer diameter ranging from 0.22 to 1.16 mm. The outer conductor layer provides electromagnetic shielding so that the electrical signals transmitted through the center conductor are less susceptible to electromagnetic waves (electromagnetic noise) from the outside.

The center conductor of micro-coax cables is described using an AWG (American Wire Gauge) Standard where the larger the AWG number, the smaller the size of the center conductor. Micro-coax cables have center conductors with AWG sizes ranging from 30 to 46 where 30 represents a center conductor 0.30 mm in diameter and 46 represents a center conductor 0.048 mm in diameter.

Micro-coax cable assemblies use micro-coax (MCX) connectors which are similar to SMB connectors but are 30% smaller in size. These connectors have a snap-on coupling design that makes installation simple and quick. Micro-coax cable assemblies operate over a limited frequency range from DC to 6 GHz only due to the small size of their center conductors. The sizes of the center conductors are not standard and may vary depending on the manufacturer.

Micro-coax cables are widely used for signal transmission between module boards inside devices such as PCs, tablets and smartphones, as well as precision instruments used for medical, industrial, automotive, aviation, etc. Due to their small size, they can easily bend around spaces in between small parts to deliver RF signals from one point to another.