Extremely thin coaxial cables (micro coaxial cable) have excellent flexibility, shielding properties, and ultra-thin structure, and are widely used in thin and light electronic products such as smartphones, laptops, vehicle systems, and medical equipment. However, in these high-speed, high-frequency signal environments, in order to maintain signal integrity and reduce reflection and interference, "impedance matching" has become a core technology that must be mastered.
What is impedance matching? Why is it so important?
In electronic devices, signals pass through multiple paths, including cables, connectors, PCB routing, and terminal modules.
If the impedance values of these paths are not consistent, reflections and echoes will occur at the impedance突变 points, leading to a decrease in signal integrity, manifested as waveform distortion, reduced speed, and even communication failure. A simple analogy: just like the flow of water in a pipeline, if the pipeline suddenly becomes narrower or wider, waves or backflow will occur at that point. The transmission of electronic signals is similar in that reflections will occur when encountering points of impedance discontinuity.
How to determine the impedance matching value?
Common signal transmission impedance standards include 50 Ω (single-ended) and 100 Ω (differential).
For example:
• HDMI, USB, LVDS and other differential signals usually use 100 Ω.
Radio frequency signals are commonly used with 50 Ω.
For the micro coaxial cable, its impedance is usually designed to be 50 Ω, and it is mainly controlled by the conductor diameter, insulation layer thickness, and dielectric constant. Due to the extremely small diameter and precise structure of the micro coaxial cable, it is more difficult to maintain impedance consistency compared to the conventional coaxial cable, especially in the connector plug-in area where impedance突变 points are easily formed. Therefore, high-quality connectors and high-precision manufacturing processes are crucial.
How to achieve impedance matching?
To ensure the impedance consistency of the micro coaxial cable assembly, attention should be paid to the following aspects:
Cable structure parameters control — including precise design of conductor diameter and dielectric material.
Connector terminal layout optimization - reduce the coupling between terminals and the impedance突变.
Welding / crimping process consistency — Ensure stable contact for each line.
Cable processing control — Reasonable bending radius and length allowance can effectively avoid impedance change.
It is worth mentioning that the I-PEX 20454-240T optimizes the terminal contact structure for high-frequency micro coaxial cables, effectively reducing impedance mutation points and significantly improving signal integrity.
Introduction to I-PEX 20454-240T connector
• Series positioning: belongs to the I-PEX CABLINE®-VS series, conforms to VESA standards, and is specifically designed for high-frequency signal applications such as notebook display panels.
Interface specifications: Support 20/30/40/50 pin multiple row types (plug housing can be adapted).
• Transmission performance: Single channel speed up to 20 Gbps, compatible with high-speed protocols such as USB4 Gen3, Thunderbolt 4, PCIe Gen4, and eDP HBR3.
Cable compatibility: compatible with AWG #38 ~ #46 extremely fine coaxial cables, standard impedance 50 Ω, some models can provide 45 Ω.
Typical applications: notebook display screens, vehicle image modules, VR/AR head-mounted displays, medical imaging equipment, and other occasions with high requirements for space and signal.
With the popularity of high-definition displays, vehicle electronics, and high-speed applications such as VR/AR, the impedance matching of micro coaxial cable with high-quality connectors becomes increasingly important. Choosing I-PEX 20454-240T paired with professional cable assembly solutions can not only reduce design and production risks but also significantly improve product signal integrity and long-term reliability.
I am Kunshan JieKangFu Precision Electronics. We have been focusing on the design and customization of high-speed signal cables and ultra-thin coaxial cables for a long time, committed to providing stable and reliable high-speed interconnection solutions to our customers. If you have any related needs or would like to learn more, please contact: Yin Manager.
18913280527（WeChat same number）。
