Antenna Coil Segmentation for Impedance Control
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Solution Overview
Problem
Conventional double-winding coils for vehicle window antennas suffer from capacitive coupling between inner and outer windings, leading to decreased impedance in the desired frequency band, which compromises signal blocking performance.
Innovation Solution
The design incorporates a coil configuration with an inner winding and an outer winding where the outer winding is shorter than the inner winding, with a specific length and turn ratio to minimize capacitive coupling, using ferrite cores and thin conducting wires to maintain high impedance in the desired frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a double-winding coil is used to reduce size, then the coil becomes more compact, but capacitive coupling between inner and outer windings decreases impedance in the desired frequency band
Solution Approach 1:
The coil is segmented into multiple windings (inner winding and outer winding) that are spatially separated along the ferrite core. The inner winding is positioned at one location while the outer winding is positioned at a different location, preventing close proximity and capacitive coupling between them. This segmentation allows the coil to maintain compact overall size while avoiding the harmful capacitive effects that would degrade signal blocking performance.
2Power
If thick conducting wire is used to handle high current, then current capacity is sufficient, but the coil becomes larger and heavier
Solution Approach 1:
The patent changes the geometric parameters of the coil design, specifically the arrangement and spacing of windings along the ferrite core, to achieve high current capacity without requiring excessively thick conductors. By optimizing the winding configuration and utilizing the ferrite core's magnetic properties, the design achieves sufficient current handling capability with lighter, thinner conducting wires, thereby reducing overall coil weight.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration results in a compact, high-impedance coil that effectively blocks signals in the desired frequency band, reducing weight and size while enhancing antenna gain.
Implementation Method 1
a coil for an antenna and an antenna system are provided in which the size of the coil is small, and high impedance can be obtained in a desired frequency band
Data Source
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Figure 5~6
AI summary
A coil for an antenna includes a ferrite core; and a winding conductor configured to have a conducting wire wound around the ferrite core as a core bar. The winding conductor includes an inner winding positioned inside when viewed from a plane perpendicular to the core bar, and an outer winding positioned outside of the inner winding. A length of the outer winding when viewed from a plane parallel to the core bar is different from a length of the inner winding.