How Hotten Engineered a 44AWG 50Ω Micro Coaxial Cable That Others Could Not Achieve

In the ultra-fine micro coaxial cable industry, many products look similar on paper. But once the application enters high-frequency transmission, ultra-small OD requirements, and connector compatibility constraints, the real engineering gap between suppliers begins to appear.

Recently, Hotten successfully developed a custom 44AWG 50Ω micro coaxial cable solution for a customer application operating at 1.25GHz high frequency transmission — a project that competing suppliers were unable to complete successfully.

This was not simply a matter of reducing cable size. The challenge required balancing:

• Stable 50Ω impedance control
• Extremely low attenuation at high frequency
• OD below 0.25mm
• Connector compatibility
• Reliable shielding performance
• Manufacturability for stable mass production

For many manufacturers, improving one parameter often causes another to fail. Hotten’s engineering team solved all of them simultaneously.

The Original Design Challenge

The customer’s specification was extremely demanding:

The OD limitation was particularly difficult because the cable also needed to match the customer’s existing connector structure. There was almost no tolerance available for increasing insulation thickness or shielding dimensions.

At the same time, high-frequency attenuation performance had to remain below 5dB — a very aggressive target for an ultra-fine 44AWG coaxial structure.

Initial Production Structure

Hotten’s original mass-production version used the following structure:

With this structure, the cable already performed close to the customer requirement. The measured attenuation value reached approximately 5.1dB at 1.25GHz over 0.5 meters.

Although technically very close, the engineering team understood that “close” is not enough in high-frequency medical, imaging, or precision electronic systems. Long-term production consistency requires sufficient engineering margin.

The remaining challenge was how to further reduce attenuation without exceeding the OD limitation.

Engineering Optimization Strategy

To achieve the final performance target, Hotten redesigned both the conductor structure and shielding system.

1. Enlarged Internal Conductor Structure

The engineering team optimized the internal conductor configuration to reduce transmission loss and improve signal efficiency under high-frequency conditions.

A larger effective conductor structure helps lower conductor resistance, which directly contributes to lower attenuation performance at GHz-level frequencies.

This optimization significantly improved signal transmission efficiency while maintaining stable impedance control.

2. Shielding Structure Optimization

The external shielding structure underwent a more critical redesign.

The original tin-plated shielding material was replaced with silver-plated material, while the shielding wire specification was reduced from 0.025 to 0.02 single wire diameter.

This improvement delivered multiple advantages simultaneously:

Reduced High-Frequency Loss

Silver plating provides better conductivity performance under high-frequency skin effect conditions compared with conventional tin plating.

At GHz frequencies, current transmission concentrates on the conductor surface. The improved surface conductivity of silver plating directly benefits attenuation performance.

Smaller Cable OD

Reducing the shielding wire diameter from 0.025 to 0.02 helped reduce the overall cable outer diameter, allowing the final structure to remain below the customer’s strict OD 0.25mm limitation.

Improved Shielding Efficiency

Despite using thinner shielding strands, the optimized structure maintained excellent shielding effectiveness while improving flexibility and manufacturability.

This balance is extremely difficult in ultra-fine coaxial cable engineering because reducing dimensions often compromises shielding integrity.

Final Result

After the structural optimization and prototype validation, Hotten successfully reduced the attenuation value to approximately 4.5dB at 1.25GHz over 0.5 meters.

The final design successfully achieved:

• Stable 50Ω impedance
• Attenuation below customer requirement
• OD below 0.25mm
• Improved shielding performance
• Connector compatibility
• Mass-production feasibility

Most importantly, this solution solved a project challenge that other suppliers were unable to complete successfully.