Z-Shaped Dual Ring NFC Antenna for Metal Sheet Coupling
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Solution Overview
Problem
Current NFC antennas fail to combine small size and high performance, with the surface-mounted type antennas having a defect where the magnetic field generated by the antenna is orthogonal to the eddy current on the metal sheet, leading to a suboptimal matched state.
Innovation Solution
A Z-shaped dual ring winding type NFC antenna is developed, featuring a ferrite core with two coils wound in a Z-shape and spirally along the vertical axis, optimizing magnetic field components to enhance performance while maintaining a small size, by utilizing a ferrite core extending along the X-Y plane and connecting coils through conductive through-holes and external electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional NFC antenna coil is placed on a battery with a ferrite layer, then the antenna performance is ensured, but the antenna size becomes large
Solution Approach 1:
The patent transitions from a planar spiral winding mode to a three-dimensional winding mode where the coil is wound around a ferrite core extending along the X-Y plane. The coil windings extend in multiple directions (X-axis, Y-axis, and Z-axis) creating a volumetric structure that achieves better magnetic field coupling with the metal sheet while maintaining a compact footprint.
Solution Approach 2:
The patent uses a composite structure combining a ferrite core with specific magnetic properties and copper wire windings. The ferrite core is designed with optimized dimensions and material properties to enhance magnetic field generation and coupling efficiency, allowing the antenna to achieve high performance in a reduced size.
2Area of stationary object
If the antenna coil is spirally wound on a ferrite core to reduce size, then the antenna size is reduced, but the magnetic field becomes orthogonal to the eddy current on the metal sheet resulting in poor matching
Solution Approach 1:
The patent introduces a three-dimensional winding configuration around a ferrite core that extends along the X-Y plane, with windings oriented along X, Y, and Z axes. This multi-dimensional arrangement creates magnetic field components that are no longer orthogonal to the metal sheet surface but instead have significant in-plane components that align with the eddy current flow, achieving optimal coupling.
Solution Approach 2:
The patent optimizes the local magnetic field distribution by carefully designing the winding directions and densities in different regions of the ferrite core. The coil windings are arranged to generate localized magnetic field components that specifically target the metal sheet interface, enhancing the coupling efficiency in critical areas.
3Object-affected harmful factors
If a ferrite layer is placed between the NFC antenna coil and battery, then eddy current effects are reduced, but the antenna must meet larger size requirements
Solution Approach 1:
The patent employs a ferrite core with optimized magnetic properties that provides both eddy current suppression and enhanced magnetic field generation. The ferrite material's high permeability and controlled conductivity allow it to shield against harmful eddy currents while simultaneously concentrating and directing the magnetic field for improved coupling with the metal sheet.
Solution Approach 2:
The ferrite core acts as an intermediary element between the coil windings and the metal sheet, mediating the magnetic field interaction. It transforms the magnetic field generated by the coil into a configuration that is optimally coupled with the metal sheet's eddy currents, while also providing electrical isolation to prevent harmful eddy currents in the battery.
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
The Z-shaped dual ring winding type NFC antenna achieves improved performance by generating magnetic field components vertical to the PCB, enhancing the antenna's efficiency and reducing size, with a 35% improvement in performance compared to traditional designs.
Implementation Method 1
two NFC antenna coils, namely a first coil and a second coil which are mutually connected and are wounded on the ferrite core
Implementation Method 2
the magnetic field generated on the antenna itself is vertical and orthogonal to the magnetic field generated by the effective eddy current which is generated on the metal sheet
Implementation Method 3
an eddy current with a positive effect is generated on the metal sheet to further improve the performance of the whole antenna system
Data Source
AI summary
The present invention discloses a Z-shaped dual ring winding type NFC antenna, comprising a ferrite core which is formed by superposing a plurality of plate-like ferrite units, a first coil and a second coil. The first coil is wounded on the outer surface of the ferrite core in a Z shape, and the second coil is spirally wound along the vertical Z axis direction. The lower end of the ferrite core is connected with an antenna insulating layer. The lower end face of the antenna insulating layer is connected with external electrodes that include a first external electrode and a second external electrode. The head end of the first coil is connected with the first external electrode, and the tail end is connected with the head end of the first coil through a connecting conductor. The tail end of the second coil is connected with the second external electrode. The “engaged” superposition of the Z-shaped first coil and the second coil which is parallel to the upper surface of the ferrite core and the magnetic field components vertical to the PCB respectively generated by the first coil and the second coil further improve the antenna performance. The first coil and the second coil make full use of the space of the ferrite core, so that the whole NFC antenna has a relatively small size.