Flexible Coaxial Cable Assembly: Why It Is Better Than FPC/FFC

The electrical industry uses FPC/FFC for jumper connections while transferring power and signals between different module boards in electrical devices, which prefer cables that support tight space, long transmission distance, and quick signal speed. As the signal transmission speed needs to increase, the flexible coaxial cable assembly has replaced the FPC/FFC.  How?

What is the flexible coaxial cable assembly?

Coaxial cables, here, means micro-coaxial cables. They have a smaller outer diameter than standard coax cables, and the size of the central conductor in a micro-coax cable ranges from AWG 30-46, where 30 means a diameter of 0.30mm and 46 means a diameter of 0.048mm. These cables take up less space and are flexible due to their smaller diameter.

These cables also have common multilayer coax cable flexible construction. They have a stranded central conductor of 7 wires covered with a dielectric or insulator. The cable assembly diameter ranges between 0.22-1.16mm. These cables get EMI and noise protection with the outer cable jacket.

The micro-coaxial cable assemblies can operate at a frequency range from Direct current to 6 GHz due to the small conductor size.

As the internet speed is increasing daily and the usage of large memory devices is also on the higher side, it has become easy to enjoy videos and high-quality images on personal computers, tablets, and smartphones. The amount of information processing is also rising along with the signal transfer speed, and this type of high-speed data transmission is not possible through FPC/FFC cables.

Due to their several advantages, flexible micro-coaxial cable assemblies are common in various demanding applications:

  • Notebook PC hinge component
  • Camera gimbal
  • Medical equipment
  • Dual-display foldable smartphone
  • Server/data center
  • AR/VR headset
coax cables

Caption: coax cables

Advantages of Micro-Coaxial Cable

As these cables have high signal transfer speeds and flexibility, these cables are becoming common in applications requiring high-speed signal features and mechanical characteristics.

High cable flexibility

The high degree of flexibility makes them perfect for various applications such as hinges and drone rotating cameras. In hinges, cables move and route multiple times. It can stabilize electrical characteristics even in bent conditions. 

Excellent impedance controllability

Micro-coaxial cables ensure the integrity of the signals with controlled impedance. The cable center conductor, insulator, and outer conductor can match and stabilize at specific impedance. The cable center conductor, insulator, and outer conductor can match and stabilize at specific impedance. The micro-coax cable secures a larger cross-sectional area than FPC/FFC cables regarding matching impedance.

Excellent shielding function

The outer conductor of micro-coaxial cables protects from electromagnetic interference keeping the signal intact. Also, the excellent shielding effect of the outer conductor reduces crosstalk between signals.

connectors used for coax cables

Caption: connectors used for coax cables

Flex Micro-coaxial cable harness assembly process

You can connect digital signals of different module boards through differential transmission ways with the help of micro-coaxial connectors. For appropriate signal transfer, ensure that the central conductor connects to the circuit signal of the board through connector contacts. Further, the outermost conductor should electrically connect to the board through metal parts in the connector. These metal parts are known as shells. This electrical connection of the external conductor to the board is referred to as grounding.

The process mainly includes these steps:

First, prepare cable sub-assembly according to types.

All micro-coaxial cables: You use only micro-coax cables of different diameters of the cable..

Micro-coax/discrete cable mix: You use micro-coax and discrete cables for transferring signals and power supply.

Ground bar with ground fingers: The finger of the ground bar directly attaches and solders to the plug. After this, the process of plug assembly becomes difficult. However, the plug harness’s electrical performance improves with the reduced cable number.

Then, set this part to the plug housing assembly portion and fix the exposed portion to the plug signal terminal through soldering.

Now, connect the lock bar part  to plug house assembly parts

Finally, cover the shell of the plug and solder it properly to complete the assembly of the plug harness

coaxial cable in 3D

Caption: coaxial cable in 3D

Benefits o fI-PEX Micro-Coaxial Connectors 

I-Pex stands at the forefront regarding the micro-coaxial connectors featuring an entire range of products used in different applications. Several features of I-Pex micro-coaxial connectors include:

  • The connectors come with a mechanical lock and EMC shielding characteristics.
  • The connectors have two mating types; horizontal and vertical.
  • You can find a variety of connectors in contact pitch options. They are available in pitch options for 0.5mm, 0.4mm, 0.3mm, and 0.25mm.


Micro-coaxial cables are an ideal choice owing to their flexible nature and high signal speed transfer. Also, these cables are best for you when your application design has limited space for routing cables. If you are looking for a high-performance cable assembly, Cloom is the right place for you. We deal in a complete range of micro-coaxial cable assemblies of all standard cable sizes ranging from 50-32 AWG. The PFA dielectric and the outer conductor layer provide excellent signal integrity. 

Hey, I am John, General manager of Cloom and OurPCB.

I am a responsible, intelligent and experienced business professional with an extensive background in the electronics industry.

Reach me at [email protected] to get a quote for your projects.


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