Bent Loop Coil Antenna With Magnetic Sheet For Compact Wireless Modules
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Solution Overview
Problem
The challenge is to create a smaller, thinner antenna module for electronic devices that can maintain communication characteristics and be mounted in a more compact space, as existing designs face interference from metal components and have difficulty adjusting resonance frequency.
Innovation Solution
An electronic apparatus with a loop coil antenna and a magnetic sheet, where the loop coil is bent and positioned alongside internal metal structures, with the magnetic sheet overlapping one side of the coil to efficiently manage magnetic flux and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna module is made smaller and thinner to reduce device size, then the space allocation is improved, but the communication characteristics deteriorate due to increased interference from metal components
Solution Approach 1:
A magnetic sheet is introduced as an intermediary component between the loop coil and the metal internal structure. The magnetic sheet has high magnetic permeability and serves as a magnetic flux guide, directing the magnetic field generated by the loop coil away from the metal structure. This prevents harmful magnetic coupling between the antenna and metal components, maintaining communication characteristics even when the antenna module is placed in compact spaces close to metal structures.
2Reliability
If a magnetic shield member is added to reduce interference from metal, then the communication characteristics are improved, but the device complexity and space requirements increase
Solution Approach 1:
The patent uses a thin magnetic sheet instead of a bulky magnetic shield member. The magnetic sheet has high magnetic permeability and can be made very thin, allowing it to be integrated into the antenna module without significantly increasing the overall thickness or complexity. The sheet is positioned between the loop coil and the metal internal structure, providing effective magnetic shielding while maintaining a compact form factor.
3Volume of moving object
If the loop coil is positioned close to the metal internal structure to save space, then the space utilization is improved, but the inductance is reduced and resonance frequency shifts
Solution Approach 1:
The magnetic sheet acts as a mediator that allows the loop coil to be positioned close to the metal internal structure without suffering from harmful magnetic coupling. The sheet guides the magnetic flux through its high permeability material, preventing the flux from interacting with the metal structure. This maintains the inductance of the loop coil and stabilizes the resonance frequency even when the antenna module is placed in compact spaces.
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 allows for a thinner antenna module that maintains communication characteristics and can be mounted in a narrower space without impairing performance, efficiently managing magnetic flux and reducing interference from metal components.
Implementation Method 1
magnetic flux generated by the antenna coil converges on the magnetic shield member
Implementation Method 2
All of these systems make use of electromagnetic induction or magnetic resonance between a primary coil and a secondary coil
Implementation Method 3
antenna device incorporated into the electronic apparatus and configured to communicate with an external device via an electromagnetic field signal
Data Source
AI summary
An electronic apparatus uses a smaller, thinner antenna module that does not have impairing communication characteristics and can also be mounted in a more narrow space. The electronic apparatus is provided with an antenna module including an antenna coil wound in a planar shape and a magnetic sheet overlapping at least a portion of the antenna coil. The antenna coil is bent, and from the bent portion, a plane that includes one side of the antenna coil on which current flows in one direction is disposed alongside a lateral face of an internal structure of a casing, and a plane that includes another side of the antenna coil on which current flows in the opposite direction than on the one side is disposed to overlap the magnetic sheet. The magnetic sheet is disposed at a position farther from a reader/writer than the other side of the antenna coil is.