NFC Antenna Module With Segmented Coil And Surrounding Shield
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Solution Overview
Problem
Handheld mobile devices with thin profiles and narrow frames face challenges in NFC antenna placement due to structural constraints, leading to potential contact with metal elements and interference with magnetic fields.
Innovation Solution
An antenna module comprising a circuit board with a conductive layer and a spiral coil, where the conductive layer surrounds the coil, and the coil is positioned in a non-wiring region of the circuit board to avoid conductive material overlap, reducing electromagnetic interference and allowing for a wide-field magnetic field generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the NFC antenna is disposed on a flexible printed circuit (FPC) in a handheld mobile device with narrow space, then the antenna can be integrated into the device structure, but the antenna inevitably contacts metal elements and generates eddy current, affecting magnetic field intensity
Solution Approach 1:
The circuit board is divided into two distinct blocks: a first block for disposing the conductive layer and a second block for disposing the spiral coil. This segmentation isolates the coil from other conductive elements, preventing eddy current interference while maintaining integration benefits.
Solution Approach 2:
The spiral coil is extracted and disposed in a dedicated non-wiring region (second block) separate from the conductive layer area. This extraction removes the coil from potential interference with other conductive elements, eliminating eddy current effects on magnetic field intensity.
2Length of moving object
If the NFC antenna is disposed in a central area of the back surface, then the device can achieve thin profile and narrow frame structure, but the antenna position becomes inconvenient for operation
Solution Approach 1:
The antenna system utilizes the vertical dimension by disposing the coil and conductive layer on opposite sides of the circuit board (first block and second block respectively). This three-dimensional arrangement allows the antenna to maintain a thin profile while providing operational convenience through proper spatial positioning.
3Object-affected harmful factors
If additional isolation materials are used to prevent eddy current interference, then magnetic field intensity can be maintained, but manufacturing costs increase
Solution Approach 1:
The circuit board structure itself provides the isolation function by dividing the board into separate blocks for conductive elements and coil. This self-service approach eliminates the need for additional isolation materials, maintaining magnetic field intensity while reducing manufacturing complexity and cost.
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 minimizes eddy current interference, maintains magnetic field intensity, and allows for accurate NFC sensing without the need for additional isolation materials, enhancing user convenience and reducing manufacturing costs.
Implementation Method 1
an antenna of near field communication (NFC) is usually disposed in a central area of a back surface
Implementation Method 2
an eddy current is generated on the metal element and intensity of a magnetic field generated by the NFC module is further affected
Data Source
AI summary
An antenna module is provided. The antenna module includes a circuit board, a conductive layer, and a spiral coil. The circuit board has a first surface and a second surface opposite to each other. The circuit board further includes a first block and a second block connected to each other. The conductive layer is disposed on the first block. The spiral coil is disposed in the second block of the circuit board. The conductive layer at least partially surrounds the spiral coil.