Combo Coil Module Magnetic Shielding for NFC and Wireless Power
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Solution Overview
Problem
Design limitations in mobile devices hinder the simultaneous integration of a wireless power receiving coil and an NFC antenna coil, as their performance characteristics and spatial arrangement must be optimized to prevent interference from metallic elements, such as a battery pack, while maintaining effective near field communication and wireless charging capabilities.
Innovation Solution
A combo coil module is designed with the NFC antenna coil and wireless power receiving coil arranged on a magnetic sheet, where the wireless power receiving coil is concentrically disposed within the NFC antenna coil, and the magnetic sheet is sized to mitigate the influence of metallic elements, with dimensions optimized based on reference listener coils to ensure high performance and minimal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wireless power receiving coil and an NFC antenna coil are simultaneously integrated in a mobile device, then both wireless charging and NFC functions are enabled, but the performance of both coils is degraded due to interference from metallic elements such as battery packs
Solution Approach 1:
A magnetic sheet is introduced as an intermediary component between the coils and metallic elements (battery pack). This magnetic sheet acts as a shield that redirects magnetic field lines, preventing them from interacting with the metallic elements that would cause interference. The magnetic sheet is positioned adjacent to the coils and extends beyond their perimeters to provide comprehensive shielding, thereby maintaining coil performance while enabling both wireless charging and NFC functions to coexist in the same mobile device.
2Area of stationary object
If the NFC antenna coil and wireless power receiving coil are arranged close together to save space, then device compactness is improved, but the NFC antenna performance is degraded due to magnetic field interference from the wireless power coil
Solution Approach 1:
A magnetic sheet is positioned between the NFC antenna coil and the wireless power receiving coil to shield the NFC antenna from magnetic field interference. The magnetic sheet redirects the magnetic field lines generated by the wireless power coil, preventing them from affecting the NFC antenna's operation. This allows both coils to be arranged in close proximity within the device while maintaining NFC antenna performance through the protective magnetic shielding.
3Reliability
If a magnetic sheet is added to shield the coils from metallic elements, then coil performance is protected, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The magnetic sheet is integrated with existing device components, particularly the battery pack assembly. The magnetic sheet can be positioned adjacent to the battery pack or combined with the battery pack housing, thereby providing shielding functionality without requiring a completely separate component. This integration approach reduces overall device complexity while still effectively protecting the coils from metallic interference.
4Power
If the wireless power receiving coil is made larger to improve charging efficiency, then wireless charging performance is improved, but the available space for NFC antenna operation is reduced
Solution Approach 1:
A magnetic sheet is positioned between the wireless power receiving coil and the NFC antenna coil to provide magnetic shielding. This allows the wireless power receiving coil to be made larger for improved charging efficiency without compromising NFC antenna performance. The magnetic sheet redirects the magnetic field lines, preventing them from interfering with the NFC antenna's operation, thereby enabling both functions to coexist in the available device space.
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 combo coil module achieves high performance for both NFC and wireless charging by isolating the coils from metallic influences, ensuring effective magnetic coupling and reducing adverse effects on the NFC antenna coil's performance, thus enabling simultaneous operation without compromising either function.
Implementation Method 1
arranged on a magnetic sheet
Implementation Method 2
NFC performs data communication at a range typically within 10 cm using a 13.56 MHz electromagnetic wave
Implementation Method 3
a wireless power receiving coil for wireless charging
Data Source
AI summary
An apparatus may include a near field communication (NFC) antenna coil and a wireless power receiving coil. The NFC antenna coil and the receiving coil may be arranged on a magnetic sheet. The wireless power receiving coil may be concentrically disposed on the magnetic sheet within an inner periphery of the NFC antenna coil. An inner diameter of the wireless power receiving coil may be greater than or equal to an inner diameter of reference listener antenna coil RL-6, of the reference listener coils specified by the NFC forum.