The core of USB4 40Gbps high-speed transmission: why must ultra-fine coaxial cable bundles be chosen?

With the transmission speed of USB4 interface climbing to 40Gbps, traditional cables are no longer able to meet the stringent requirements of high-frequency signals for impedance, loss, and shielding performance. To achieve stable, high-speed, and low-loss transmission in limited spaces, extremely thin coaxial cables (Micro Coaxial Cable) have become the mainstream choice in the field of high-speed interconnects. Their structural advantages and electrical characteristics make them an indispensable key component for thin and light devices and high-performance systems.

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Structure and inherent advantages of ultra-fine coaxial beam

The ultra-fine coaxial cable bundle consists of a central conductor, insulating medium, shielding layer, and outer sheath, forming a complete coaxial structure that ensures a highly independent signal path and excellent electromagnetic constraint ability. For interfaces like USB4 that operate at GHz levels, EMI control and signal integrity are crucial, and the coaxial design of micro coax can achieve low crosstalk, high shielding, and high consistency transmission in a compact space. Therefore, it is widely used in high-speed links of notebook motherboards, AI servers, camera modules, and various portable devices.

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Core technology capability supporting 40Gbps

The ultra-fine coaxial cable束 can meet the high-speed transmission requirements of USB4 mainly due to four key performance features: precise impedance control ensures that high-speed signals do not produce excessive reflections; low insertion loss is attributed to the use of high-purity conductors and low dielectric constant materials, which maintain clear high-frequency signals; strong shielding structure reduces external noise and cross-talk between the wires; and miniaturization and flexible design allow it to achieve bending, wiring, and long-term reliable use at a wire diameter of 0.3–0.5mm. These capabilities collectively ensure the eye diagram quality and transmission stability of USB4 during high-speed operation.

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Key Challenges and Countermeasures in Engineering Practice

In actual development, it is not an easy task to ensure that the harness can stably operate at 40Gbps. Long transmission paths can lead to high-frequency attenuation, so it is necessary to shorten the link as much as possible and match it with equalization circuits; impedance discontinuities may cause reflections, which need to be optimized through TDR testing to ensure structural consistency; connectors need to adopt models specifically designed for high-speed protocols such as I-PEX, JAE, etc.; and improve mechanical reliability by controlling the bending radius and reinforcing the shielding layer material. Only through comprehensive coordination from design to manufacturing can micro coax fully release its high-speed transmission performance.

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The ultra-fine coaxial cable can support the high-speed transmission of 40Gbps for USB4, relying on its low loss, strong shielding, high consistency, and flexible miniaturization, making it one of the core components in the modern high-speed interconnection system. In fields such as AI computing, consumer electronics, and industrial control, micro coax is becoming the preferred solution for high-bandwidth links.

I am[Suzhou Huichengyuan Electronic Technology], Focused on the development and customization of high-speed signal cables and ultra-fine coaxial cables for many years, providing reliable and high-performance interconnection solutions to customers. Welcome to contactManager Zhang: 18913228573 (WeChat same number)。