Shredded Ferrite Shielding for Flexible NFC Antennas
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Solution Overview
Problem
Conventional magnetic field shielding materials for portable devices face challenges in maintaining high magnetic permeability across a wide frequency band, leading to performance degradation and increased thickness, while also being prone to breakage from external impacts, which affects the efficiency and durability of antennas for NFC, WPT, and MST functions.
Innovation Solution
A magnetic field shielding unit using shredded ferrite containing magnesium oxide with irregular shapes and specific composition ratios, including copper oxide, nickel oxide, and zinc oxide, is developed to enhance flexibility and maintain initial magnetic properties, preventing fragmentation and improving transmission efficiency across various frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic field shielding materials are used to maintain high magnetic permeability across a wide frequency band, then transmission efficiency is improved, but the material becomes prone to breakage from external impacts
Solution Approach 1:
The patent uses ferrite particles dispersed in a flexible polymer matrix to create a composite magnetic shielding material. The ferrite particles provide high magnetic permeability for efficient signal transmission, while the polymer matrix provides flexibility and resistance to external impacts, preventing breakage and maintaining durability.
Solution Approach 2:
The patent changes the physical state of the magnetic material from solid rigid ferrite to a flexible composite by controlling particle size (1-10 μm) and dispersion in the polymer matrix. This parameter change allows the material to maintain magnetic properties while gaining flexibility and impact resistance.
2Length of moving object
If magnetic field shielding material is made thinner to achieve slim device design, then device thickness is reduced, but the material becomes more susceptible to breakage and performance degradation
Solution Approach 1:
The patent creates a thin-film flexible magnetic shielding material by dispersing fine ferrite particles (1-10 μm) in a polymer matrix. This flexible film structure can be made very thin while maintaining integrity and magnetic shielding performance, enabling slim device design without sacrificing durability.
Solution Approach 2:
The composite structure of ferrite particles in a polymer matrix allows the material to be made thin while the polymer provides mechanical strength and flexibility, preventing breakage even at reduced thickness.
3Reliability
If integrated magnetic shielding materials are used for multiple frequency bands, then shielding performance across all bands is improved, but the material thickness increases
Solution Approach 1:
The patent develops a universal magnetic shielding material using ferrite particles with specific size range (1-10 μm) that provides effective shielding across multiple frequency bands (including NFC, WPT, and MST). This single multi-functional material eliminates the need for separate shielding layers for different frequencies, maintaining thin overall thickness.
Solution Approach 2:
By optimizing ferrite particle size (1-10 μm) and concentration in the polymer matrix, the material achieves broad frequency band shielding performance in a single thin layer, avoiding the need for multiple thick layers tuned to different frequencies.
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 significantly increases the transmission efficiency and reception distance of signals for NFC, WPT, and MST antennas, while maintaining the initial designed physical properties and preventing deterioration due to external impacts, allowing for a slim and durable module design.
Implementation Method 1
The magnetic permeability varies depending on the type of the magnetic body included in the magnetic field shielding material... the real part (μ′) of complex permeability of 650 or more at a frequency of 100 kHz
Implementation Method 2
the magnetic field shielding material induces the concentration of the magnetic field between the transmitting and receiving parts, thereby improving the transmission and reception
Data Source
AI summary
Disclosed is a magnetic field shielding unit for magnetic security transmission. The magnetic field shielding unit for magnetic security transmission includes a magnetic shielding layer formed of fragments of ferrite containing magnesium oxide (MgO) shredded to improve flexibility of the magnetic field shielding unit. The ferrite containing magnesium oxide has a real part (μ′) of the complex permeability of 650 or more at a frequency of 100 kHz. Accordingly, it is possible to prevent influence of a magnetic field on components of a mobile terminal device or a body of a user who uses the same, and to further increase the characteristics of the combined antennas even if the magnetic field shielding unit is combined with various kinds and purposes of antennas having various structures, shapes, sizes and intrinsic characteristics (inductance, resistivity, etc.).