Common Mode Filter Hexaferrite Particles High Frequency Noise
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Solution Overview
Problem
Existing common mode filters struggle to effectively filter high-frequency common mode noise due to limitations in magnetic permeability and increased loss characteristics, particularly in the GHz band, which affects their ability to block noise while allowing differential mode signals to pass.
Innovation Solution
A common mode filter utilizing ferrite particles with uniform size and planar magnetic anisotropy, such as hexaferrite particles, is designed to enhance magnetic permeability and reduce loss, allowing for improved attenuation characteristics by adjusting the size, length, and orientation of these particles within a magnetic substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic materials are used in common mode filters, then the filter can operate at lower frequencies, but magnetic permeability decreases and loss increases at high frequencies (GHz band)
Solution Approach 1:
The patent changes the physical and chemical parameters of the magnetic material by using ferrite particles with specific characteristics: uniform size distribution (5-50 μm), high magnetic permeability (μr>100), and controlled saturation magnetization (100-300 emu/cm³). These parameter changes enable the filter to maintain low loss and high magnetic permeability at GHz frequencies, resolving the contradiction between reliability and energy loss.
Solution Approach 2:
The patent employs a composite magnetic substrate consisting of ferrite particles dispersed in a binder resin. This composite structure combines the high magnetic permeability of ferrite particles with the mechanical stability of the binder, achieving both low loss at high frequencies and structural integrity. The composite material approach allows optimization of magnetic properties while maintaining manufacturability.
2Object-affected harmful factors
If high magnetic permeability materials are used to block common mode noise, then noise attenuation improves, but the filter becomes less effective at high frequencies due to increased loss
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: particle size (5-50 μm), magnetic permeability (μr>100), and saturation magnetization (100-300 emu/cm³). This multi-parameter optimization enables the material to achieve both high noise attenuation and maintained performance at high frequencies, resolving the contradiction between noise blocking effectiveness and high frequency reliability.
Solution Approach 2:
The patent applies local quality by creating a non-uniform distribution of ferrite particles within the magnetic substrate, with higher particle concentration in regions where common mode noise attenuation is most critical. This localized optimization allows enhanced noise blocking in specific areas while maintaining overall high frequency performance.
3Loss of energy
If ferrite particles with uniform size and planar structure are used, then magnetic permeability and high frequency characteristics improve, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-synthesizing ferrite particles with uniform size and controlled morphology before incorporating them into the magnetic substrate. This advance preparation ensures consistent magnetic properties without requiring complex in-situ control during final assembly, resolving the contradiction between performance and manufacturability.
Solution Approach 2:
The patent specifies precise particle parameters (uniform size 5-50 μm, planar structure, high magnetic permeability) that can be controlled during particle synthesis. By establishing these parameters in advance during material fabrication rather than during filter assembly, the patent achieves high performance while maintaining ease of manufacture.
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 filter achieves better attenuation of high-frequency common mode noise with low loss, improving its performance across the GHz band by leveraging the high magnetic permeability and low loss characteristics of hexaferrite particles, thereby enhancing noise filtering efficiency.
Implementation Method 1
impedance may be associated with the magnetic permeability of a magnetic material
Implementation Method 2
ferrite particles having anisotropy and a planar structure have planar magnetic anisotropy
Implementation Method 3
hexaferrite particles having a uniform size and planar magnetic anisotropy such as hexaferrite particles
Data Source
AI summary
A common mode filter includes a magnetic substrate in which ferrite particles having anisotropy and a planar structure are disposed to have a planar orientation.