Ultra-thin coaxial cable assembly selection guide: Small size can also achieve high-speed and stable transmission

In products that continuously pursue miniaturization and high performance, such as smartphones, camera modules, medical probes, and wearable devices, extremely thin coaxial cables (Micro Coaxial Cable) have become the preferred solution for high-speed signal transmission and space utilization. They not only offer excellent electromagnetic shielding but also maintain flexibility and reliability in extremely small installation spaces. However, selecting a cable with matching performance is not an easy task—the wire diameter, impedance, shielding layer, and bend life are all factors that will directly affect the final performance. Below, we will gradually analyze the key points for selecting extremely thin coaxial cables.

What is a ultra-fine coaxial cable bundle?
The diameter of extremely fine coaxial cable bundles is usually around 1 millimeter, even finer. Its internal structure still follows the standard coaxial design: consisting of a central conductor, insulation layer, shielding layer, and outer sheath. Despite its small size, it still ensures high-quality signal transmission performance, and is therefore widely used in fields that require extremely high signal integrity, such as high-speed interfaces, radio frequency signals, ultrasonic detection, and image transmission.

Two, key parameters to pay attention to when selecting
1. Wire diameter (AWG conductor thickness)
The finer the conductor, the better the flexibility, the smaller the volume, but the resistance will also increase accordingly. Common specifications include 38AWG, 40AWG, and 42AWG. If a larger current or a longer distance signal needs to be transmitted, a slightly thicker wire diameter should be chosen to reduce losses and impedance.
Impedance matching
Impedance mismatch can cause signal reflection and distortion. Common standards are 50Ω or 45Ω. In high-speed interfaces or radio frequency applications, the overall system impedance matching must be considered in the selection of lines, connectors, and PCB design.
3. Outer diameter and flexibility
The diameter size affects the wiring space and bending performance. During design, it is necessary to confirm the bending radius and bending life indicators to ensure the long-term reliable operation of the cable harness in dynamic structures.
4, performance blocking
The coverage of the shielding layer is directly related to the anti-interference ability. For high-speed video transmission or medical ultrasonic applications, it is recommended to prioritize the use of wire materials with perfect shielding structures and high density.
5. Material and environmental adaptability
The dielectric constant of the insulation layer affects the characteristics of high-frequency signals, while the material of the outer sheath determines its temperature resistance, moisture resistance, and chemical resistance. In medical, vehicle-mounted, or industrial environments, material stability and durability are particularly important.

Section 3: Recommended Selection Process
1. Clarify the application scenario: confirm whether it is for high-speed signal, radio frequency signal, or power transmission.
Determine basic parameters: Based on current and frequency requirements, preliminarily select wire diameter and impedance range.
3. Consider the installation environment: assess whether it is necessary to bend frequently, and whether it operates in high-temperature or humid environments.
Sample verification: Verify whether the performance meets the requirements through tests such as insertion loss, reflection, and bend life.
5. Balancing trade-offs: Find the optimal solution between performance, cost, and supply stability.

Four, Analysis of Common Misconceptions
1. Blind pursuit of finer wire diameter: Finer wire does not necessarily mean better; excessively fine wire may cause greater signal loss and lower mechanical strength.
Ignoring connector constraints: the pin spacing of connectors and the insertion-extraction life will affect the selection and matching of wiring harnesses.
3. Not verifying parameters: Paper data may be good, but if it has not been verified in practice, there may be problems such as signal attenuation or core breakage when applied.

The selection of ultra-fine coaxial cable bundles is a "balance art." To find the optimal solution among space constraints, frequency requirements, impedance matching, flexibility, and cost, a combination of experience, testing, and reasonable planning is required. Only with a well-designed preliminary design can the stability and reliability of the final product be ensured.
I am[Suzhou Huichengyuan Electronic], focused on the research, development, and customization of high-speed signal cables and ultra-fine coaxial cables. We are committed to providing customers with high-stability high-speed interconnection solutions. If you have any related needs or want to learn more, please feel free to contact us:Manager Zhang 18913228573 (WeChat same number)。