Core-Shell Iron Oxide Absorber for EMI Suppression
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Solution Overview
Problem
Current methods for suppressing electromagnetic interference (EMI) in high-density, multi-antenna integration packaging are inadequate, as they only reflect external electromagnetic waves without addressing internal radiated interference and high-order noise harmonics, leading to reduced communication quality and increased costs.
Innovation Solution
A core-shell electromagnetic wave absorbing material is developed, comprising an iron oxide core with a magnetic moment and a shell layer made of an inorganic compound, which has a lower thermal expansion coefficient, along with an amorphous intermediate layer, to effectively absorb electromagnetic waves and regulate thermal expansion, enabling the material to suppress both external and internal EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal layer is coated outside a module to isolate electromagnetic waves, then external electromagnetic interference is reflected and eliminated, but internal radiated electromagnetic interference and high-order noise harmonics cannot be suppressed
Solution Approach 1:
The electromagnetic interference suppression is segmented into two distinct functional layers: a metal layer for reflecting external electromagnetic waves and an absorbing material layer for absorbing internal radiated interference and high-order noise harmonics. This segmentation allows each layer to address specific types of interference without compromising the other function.
Solution Approach 2:
The invention uses a composite structure combining a metal layer with an absorbing material layer made of magnetic particles embedded in a polymer matrix. This composite material configuration enables simultaneous reflection of external electromagnetic waves by the metal layer and absorption of internal radiated interference by the magnetic particle-containing layer.
2Productivity
If high-density, thin, and multi-antenna integration packaging is implemented, then communication technology development is advanced, but spacing between components is reduced causing strong electromagnetic coupling effect and interference
Solution Approach 1:
The absorbing material layer acts as an intermediary substance placed between closely spaced components and antennas. This intermediary layer absorbs electromagnetic waves that would otherwise cause coupling and interference, enabling high-density integration while maintaining signal integrity.
Solution Approach 2:
The invention changes the physical parameters of the packaging system by introducing materials with specific electromagnetic properties (magnetic particles with high permeability) that alter the electromagnetic field distribution and reduce coupling effects between closely spaced components.
3Reliability
If electromagnetic interference suppression materials are added to improve communication quality, then signal strength and reliability are maintained, but manufacturing process complexity and cost increase
Solution Approach 1:
The absorbing material is preliminarily mixed into the molding compound before the injection molding process. This preliminary action allows the electromagnetic interference suppression functionality to be integrated into the packaging structure during the standard molding process, avoiding additional manufacturing steps and reducing overall complexity.
Solution Approach 2:
The polymer matrix serves multiple functions: it provides the structural packaging material, acts as a binder for magnetic particles, and enables injection molding processing. This multi-functionality reduces the need for separate components and manufacturing steps, thereby reducing device complexity while maintaining reliability.
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 material achieves high-frequency electromagnetic wave absorption and thermal management, improving communication quality by reducing EMI and maintaining signal strength, while being compatible with silicon or gallium nitride substrates.
Implementation Method 1
a core, containing an iron oxide and having a first thermal expansion coefficient
Implementation Method 2
the shell layer has a second thermal expansion coefficient less than the first thermal expansion coefficient
Implementation Method 3
sintering the combination at a high temperature to form a core and a shell layer, wherein materials of the core and the shell layer diffuse with each other
Data Source
AI summary
The present disclosure provides an electromagnetic wave absorbing material, including a core containing iron oxide having a first thermal expansion coefficient; and a shell layer covering the core, which has a second thermal expansion coefficient less than the first thermal expansion coefficient, and the shell layer contains an inorganic compound selected from a group consisting of oxides, nitrides or any combination thereof. The present disclosure further provides a composite structure for suppressing electromagnetic interference including the electromagnetic wave absorbing material as claimed.