Double-Shielded Coaxial Cable for Flexible High-Frequency Antennas
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Solution Overview
Problem
Existing shielded cables for portable electronic devices, such as mobile phones, face issues with high-frequency signal loss, rigidity, and flexibility, particularly when used as antennas, due to their thick and heavy design, which affects resonance frequency and gain, especially when held by a human body.
Innovation Solution
A double-shielded coaxial cable design with braided shields and aramid fiber reinforcement, featuring a coaxial structure with adjustable impedance and a folded shield configuration to enhance flexibility and high-frequency performance, reducing signal loss and improving antenna gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an ordinary coaxial cable (3C-2V or 5C-2V) is optimized for high-frequency signal transmission, then high-frequency transmission characteristic is improved, but the cable becomes thick, heavy, and low in flexibility
Solution Approach 1:
The patent changes the physical parameters of the cable by using a composite conductor structure with fine wire strands (0.03-0.07mm diameter) instead of traditional thick conductors. This allows achieving low signal loss through optimized strand configuration while reducing overall cable diameter and weight to 1/3-1/2 of conventional cables.
Solution Approach 2:
The patent employs composite material construction by combining multiple fine copper wire strands with a polyurethane foam insulator and braided shield. This composite structure achieves excellent high-frequency transmission characteristics while maintaining flexibility and reducing weight compared to solid conductor designs.
2Loss of energy
If an ordinary coaxial cable is optimized for high-frequency signal transmission, then high-frequency transmission characteristic is improved, but flexibility and tensile properties deteriorate
Solution Approach 1:
The patent divides the conductor into multiple fine wire strands (2-7 strands per core) rather than using a single thick conductor. This segmentation allows the cable to bend more easily while maintaining electrical continuity and low signal loss, significantly improving flexibility for portable device applications.
Solution Approach 2:
The patent uses a polyurethane foam insulator and a flexible braided shield configuration that provides mechanical protection while allowing the cable to flex. The thin-walled construction with optimized layer thicknesses enables the cable to bend without damage, achieving both flexibility and durability.
3Loss of energy
If a sleeve antenna with folded ground structure is used, then high-frequency impedance is increased to block electric current, but the structure becomes complicated and larger in size
Solution Approach 1:
The patent extracts the essential function of the folded ground structure by implementing a simplified single-layer braided shield configuration. This extraction maintains the high-frequency current blocking capability while eliminating the complex folded geometry, resulting in a more compact and easier-to-manufacture antenna structure.
Solution Approach 2:
Instead of using a traditional folded ground structure that increases impedance through geometric complexity, the patent inverts the approach by using a single-layer braided shield with optimized material properties and configuration to achieve the same impedance effect, simplifying the overall structure.
4Loss of energy
If a coaxial cable with thick construction is used for high-frequency transmission, then signal transmission quality is improved, but the cable becomes heavy and low in flexibility
Solution Approach 1:
The patent changes the conductor configuration from thick solid or few-strand wires to multiple fine wire strands (0.03-0.07mm diameter). This parameter change reduces the overall cable diameter and weight while maintaining low signal transmission loss through optimized strand arrangement and material properties.
Solution Approach 2:
The patent uses a composite construction combining fine copper wire strands with polyurethane foam insulator and braided shield. This composite material approach achieves excellent signal transmission characteristics with reduced weight and improved flexibility compared to traditional thick-walled coaxial cables.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A shielded cable includes an inner conductor, a first insulator, a first outer conductor, a second insulator, and a second outer conductor, which are coaxially disposed in this order from an inner side, and has an outer circumference coated by an insulation sheath.