Magnetic Iron Oxide Absorber Composition for Multi-Band THz Absorption
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Solution Overview
Problem
Current electromagnetic-wave absorbers are inadequate for effectively absorbing electromagnetic waves across a wide range of frequencies above the millimeter-wave band, particularly in the terahertz range, limiting their ability to prevent wave leakage in advanced wireless communication and radar systems.
Innovation Solution
An electromagnetic-wave absorber composition comprising multiple magnetic iron oxides with distinct coercive forces and magnetic resonance frequencies, separated by 5 GHz or more, is used to create an electromagnetic-wave absorbing layer that differentiates a magnetic property hysteresis loop, allowing for the absorption of multiple frequencies in the high-frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single type of magnetic iron oxide is used in the absorber, then the structure is simple and easy to manufacture, but the absorber can only effectively absorb electromagnetic waves at a specific frequency
Solution Approach 1:
The absorber is segmented into multiple functional components by incorporating different types of magnetic iron oxides (e.g., magnetite, maghemite, gamma-fe2o3) with distinct magnetic resonance frequencies. Each oxide type targets specific frequency bands, dividing the overall absorption function into specialized sub-functions that collectively cover a broader spectrum from millimeter-wave to terahertz ranges.
Solution Approach 2:
The invention uses composite materials by combining multiple magnetic iron oxide phases with different coercive forces and resonance characteristics. This composite approach leverages the complementary properties of each oxide type to achieve broad-band absorption, where magnetite contributes to lower frequency absorption while maghemite and gamma-fe2o3 enhance higher frequency absorption up to terahertz bands.
2Adaptability or versatility
If multiple types of magnetic iron oxides with different coercive forces are used, then electromagnetic waves of multiple frequencies can be absorbed, but the manufacturing process becomes more complex
Solution Approach 1:
The invention utilizes parameter changes by varying the magnetic properties (coercive force, saturation magnetization) of the iron oxide phases to tune the absorption characteristics. By controlling the ratio and particle size distribution of different oxide types, the absorber can be optimized for specific frequency ranges while maintaining a relatively simple manufacturing process using conventional ceramic or powder metallurgy techniques.
3Adaptability or versatility
If the absorber is designed for high-frequency absorption in the terahertz band, then it can handle advanced wireless communication and radar applications, but the design becomes more complex compared to conventional absorbers
Solution Approach 1:
The absorber achieves universality by designing a multi-phase magnetic iron oxide composition that simultaneously serves multiple functions: absorbing millimeter-wave frequencies for radar applications, absorbing terahertz frequencies for high-speed wireless communication, and providing broadband coverage. This single composite material replaces the need for multiple specialized absorbers for different frequency bands and applications.
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 absorber effectively absorbs electromagnetic waves of various frequencies in the millimeter-wave and terahertz bands, enhancing the prevention of wave leakage and improving the performance of wireless communication and radar systems.
Implementation Method 1
the absorber includes a plurality of magnetic iron oxides having coercive forces different from one another and magnetic resonance frequencies having a difference of 5 GHz or more between the magnetic resonance frequencies
Implementation Method 2
two or more extrema which are separated from one another on a differential curve obtained by differentiating a magnetic property hysteresis loop
Data Source
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Figure 3~4
AI summary
The present invention achieves an electromagnetic wave absorbing composition and an electromagnetic wave absorbing body which can excellently absorb a plurality of types of electromagnetic waves of different frequencies in a frequency band higher than the millimeter wave band. This electromagnetic wave absorbing composition contains a magnetic iron oxide 1a which magnetically resonates at high frequencies equal to or higher than frequencies in the millimeter wave band and a resin binder 1b, and has at least two separate extrema on a differential curve obtained by differentiating a hysteresis loop of magnetic characteristic in an applied magnetic field between -16 kOe to 16 kOe. In addition, the electromagnetic wave absorbing body is provided with an electromagnetic wave absorbing layer formed by the electromagnetic wave absorbing composition.