How to make ultra-thin coaxial cables quieter? Anti-interference techniques in high-frequency systems

In modern electronic systems, micro coaxial cable has become a key channel for high-density signal transmission, widely used in scenarios that require extremely high standards for space and signal quality, such as laptops, folding-screen smartphones, medical equipment, AR/VR headsets, and others. This type of cable has a compact structure and excellent flexibility, maintaining stable signal transmission even in environments with frequent bending. At the same time, its outer conductor has shielding functions, effectively preventing electromagnetic interference (EMI) and external noise intrusion. However, even with excellent design, micro coaxial cables may still encounter various signal interference issues in complex applications.

Common signal interference problems in ultra-fine coaxial cables
Shielding layer imperfect leading to interference
Although the coaxial structure itself has good shielding characteristics, if the shielding layer resistance is too high, it may cause common-mode current or residual voltage in the low frequency band (such as below 30 MHz), affecting signal reception. In addition, when the shielding layer adopts a copper wire mesh structure, the weaving gaps may also allow high-frequency noise to渗透, reducing the purity of the signal.
Dirt road and sheath current interference
When the ground potential of the two ends of the connected devices is inconsistent, it may form sheath current flowing along the shielding layer, which is superimposed on the effective signal, causing signal distortion or noise interference.
Connector contact is poor or impedance mismatch
If the harness cannot achieve a 360° full shielding contact with the connector, or if the characteristic impedance mismatch is improper, it may lead to signal reflection, image ghosting, or even data errors.
Power interference and switch noise radiation
High-frequency switching power supplies often generate spurious radiation signals. If proper filtering measures are lacking, these noises may couple into the coaxial system through cables, causing crosstalk or performance degradation.

Effective interference suppression measures
Enhance the shielding structure
The composite shielding design using "metal foil + copper braided layer" can provide excellent interference suppression effect simultaneously in the low-frequency and high-frequency ranges.
② Suppress sheath current interference
Ferrite Bead/Choke: Installed at the end of the cable or near the equipment, it can effectively absorb high-frequency common-mode noise.
Capacitive coupling ground isolator: Suitable for high-frequency systems, capable of blocking low-frequency ground loop interference while ensuring normal transmission of the signal path.
Ensure impedance matching and reliable connections
Select a coaxial cable with characteristic impedance matching (such as 45 Ω or 50 Ω) and connectors, and ensure complete shielding contact at the interface, which can significantly reduce signal reflection and loss.
Source Control and Rational Wiring
Increase filtering circuits or metal shielding covers at the interference source (such as switch-mode power supplies) to weaken scattered radiation.
Avoid laying out the same-axis lines parallel to the strong interference signal lines in the system layout; use metal tube shielding or staggered wiring methods when necessary to reduce coupling.
Micro coaxial cable, although extremely small in size, its structural design and shielding performance are crucial to signal quality. In practical applications, attention should be focused on shielding integrity, ground loop management, impedance matching, and power noise control. By strengthening the shielding layer, installing common-mode filters, optimizing wiring and termination methods, interference can be effectively reduced, ensuring the integrity and stability of high-speed signals.
I am[Suzhou Huichengyuan Electronic], Focus on the research and development and customization of high-speed signal cables and ultra-fine coaxial cables, committed to providing customers with high-performance and reliable interconnection solutions. For more product information or customization services, please contact:Manager Zhang 18913228573 (WeChat number same)。