Surface Mounted NFC Antenna Back-Coupling Reduction
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Solution Overview
Problem
Traditional surface mounted NFC antennas face challenges in miniaturization and performance due to orthogonal magnetic field orientations, which hinder optimal matching with eddy currents generated on metal sheets, leading to reduced antenna efficiency.
Innovation Solution
A surface mounted NFC antenna design featuring a magnetic core, first and second coils, and dielectric layers, where the second coil is positioned on a dielectric layer outside the magnetic core to minimize back-coupling, with a turns ratio of 0.2:0.4 and spirally wound along the magnetic core's length or width, enhancing separation and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second coil is wound orthogonally on the ferrite core to improve antenna performance, then the magnetic field coverage is enhanced, but the back-coupling between coils increases and weakens the magnetic field
Solution Approach 1:
The patent introduces a dielectric layer as an intermediary substance between the first coil and the second coil. This dielectric layer acts as a mediator that reduces the magnetic coupling between the two orthogonally wound coils, thereby weakening the back-coupling effect while maintaining the orthogonal winding configuration's performance benefits
Solution Approach 2:
The patent segments the antenna structure by separating the two coils with a dielectric layer, dividing the magnetic field generation function into distinct zones. This segmentation reduces the interaction between coils while preserving the overall antenna performance through controlled field distribution
2Volume of moving object
If the antenna coil is spirally wound on a ferrite core to miniaturize the antenna size, then the antenna dimensions are reduced, but the magnetic field orientation becomes orthogonal to the eddy current field on metal sheets
Solution Approach 1:
The patent transitions from a single-plane spiral winding to a three-dimensional orthogonal winding structure. By adding the vertical dimension with the second coil wound perpendicular to the first coil, the antenna achieves both miniaturization through compact volume utilization and improved magnetic field matching through multi-directional field components
Solution Approach 2:
The patent employs a composite structure combining ferrite core material with dielectric layer material. This composite construction enables simultaneous achievement of magnetic field concentration (from ferrite) and back-coupling reduction (from dielectric), resolving the contradiction between size reduction and field matching
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 design reduces back-coupling effects, allowing the magnetic field of the second coil to remain strong, improving overall antenna performance by positively superposing the eddy loop's magnetic field with the first coil's field, thus achieving better matching and efficiency.
Implementation Method 1
Near Field Communication (NFC) is a wireless communication technology which helps electronic devices receive and transmit electromagnetic waves by means of magnetic field induction
Implementation Method 2
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
Herein disclosed is a surface-mounted NFC antenna, having a small size and good performance, comprising a magnetic core, a first dielectric layer, a first coil and a second coil. The first coil is wound on the outer surface of the magnetic core. One side of the first dielectric layer, away from the magnetic core, is the first surface. The second coil is disposed on the first surface. The tail end of the first coil is electrically connected with the head end of the second coil. In the NFC antenna, the second coil is disposed on the dielectric layer to separate the first coil from the second coil, thereby preventing the magnetic field generated by the first coil from weakening the magnetic field generated by the second coil, so the magnetic field generated by the second coil is relatively larger.