Planar Loop Coil Asymmetric Magnetic Sheet Resonance Stability
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Solution Overview
Problem
Conventional loop coil antennas in electronic devices face challenges such as large variations in resonance frequency, difficulty in adjusting distributed capacitance, and inefficient magnetic flux coupling, leading to suboptimal communication characteristics.
Innovation Solution
Incorporating a planar loop coil with a sheet-shaped magnetic material that overlaps with the loop coil on one side, allowing for efficient magnetic flux capture and reduced counter-current generation, thereby enhancing communication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a loop coil is arranged in a clearance in a housing, then the antenna can be integrated into the device, but it is difficult to form the antenna in a constant shape and the amount of change of inductance is large, resulting in large variation of resonance frequency
Solution Approach 1:
A magnetic sheet is selectively placed only on one side of the center of the loop coil, creating asymmetric magnetic flux distribution. This local modification stabilizes the inductance by concentrating magnetic flux in a controlled region, thereby reducing resonance frequency variation while maintaining device integration.
Solution Approach 2:
The magnetic sheet acts as an intermediary element between the loop coil and the housing clearance. It mediates the magnetic flux distribution, providing a stable magnetic path that compensates for the irregularities introduced by the clearance arrangement, thus stabilizing resonance frequency.
2Adaptability or versatility
If the loop coil is formed by a flexible cable, then the antenna can be arranged in clearance, but it is difficult to adjust distributed capacitance between wirings, requiring a lot of man-hours to adjust the resonance frequency
Solution Approach 1:
The magnetic sheet is positioned to automatically concentrate magnetic flux on one side of the loop coil, creating an asymmetric configuration that self-adjusts the resonant characteristics. This reduces the need for manual capacitance adjustment by providing inherent magnetic flux management that stabilizes resonance frequency.
3Power
If magnetic fluxes from the reader/writer pass through the loop coil, then power transmission occurs, but currents are generated in directions opposite to each other on opposite sides of the loop coil, preventing efficient coupling
Solution Approach 1:
The magnetic sheet is asymmetrically positioned on only one side of the loop coil's center, creating unequal magnetic flux distribution across the coil. This asymmetry causes the magnetic flux to concentrate on one side, generating currents in the same direction rather than opposite directions, thereby improving coupling efficiency and power transmission reliability.
Solution Approach 2:
By placing the magnetic sheet locally on one side of the loop coil, the magnetic flux is concentrated in a specific region. This local concentration of magnetic flux ensures that currents are generated consistently in one direction on the side with the magnetic sheet, improving coupling efficiency while maintaining power transmission capability.
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 solution achieves improved communication characteristics by efficiently drawing in magnetic flux and reducing counter-currents, resulting in more stable and effective communication performance.
Implementation Method 1
the magnetic sheet is overlapped with the one side of the center of the loop coil, so that it is possible to efficiently draw in magnetic fluxes on the one side
Implementation Method 2
magnetic fluxes from the reader/writer which pass through the loop coil generate currents in directions opposite to each other
Data Source
AI summary
An electronic device incorporated with a coil module that achieves favorable communication characteristics is provided. In an electronic device incorporated with a coil module, the coil module includes a loop coil wounded in a planar shape and a sheet-shaped magnetic sheet which is formed of a magnetic material and which overlaps with a part of the loop coil, and the magnetic sheet is arranged on at least one side extending from a center of the loop coil.