Magnetic Material for Antenna Size Reduction
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Solution Overview
Problem
Existing antennas face challenges in size reduction while maintaining wide frequency bandwidth and efficiency, particularly at high frequencies, due to limitations in magnetic materials such as excessive magnetic loss, limited frequency bands, and difficulties in mass production with nanoparticle-based solutions.
Innovation Solution
A magnetic material comprising a M-type hexagonal ferrite with an average crystal particle diameter of 5 μm or more, represented by the formula MA.Fe12-x.MBx.O19, which increases the real part of relative permeability and suppresses magnetic loss, allowing for a wider bandwidth and efficient size reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a material with large relative permittivity is used to shorten wavelength and reduce antenna size, then the antenna size is reduced, but the frequency band that obtains high efficiency is narrowed
Solution Approach 1:
The patent changes the material parameter from large relative permittivity to large relative permeability (μr≥2.0). This parameter substitution allows wavelength shortening for size reduction while avoiding the frequency band limitation problem that occurs with high permittivity materials.
Solution Approach 2:
The patent uses composite magnetic materials including ferrite particles (0.1-10 μm), Y-type hexagonal ferrite, and M-type hexagonal ferrite to achieve both size reduction and wide frequency band operation. The composite structure combines the advantages of different magnetic materials to maintain efficiency across multiple frequency bands.
2Speed
If Y-type hexagonal ferrite is used as magnetic material, then the antenna can operate at high frequencies, but magnetic loss becomes excessive and available frequency band is limited
Solution Approach 1:
The patent creates a composite material system combining ferrite particles with Y-type and M-type hexagonal ferrite. This composite structure balances high-frequency operation capability with reduced magnetic loss, allowing efficient operation across a wide frequency range including GHz bands.
Solution Approach 2:
The patent optimizes the particle size distribution (0.1-10 μm) and compositional ratios of different ferrite phases to achieve local optimization of magnetic properties. This allows different regions of the material to contribute differently to high-frequency performance and loss reduction.
3Volume of moving object
If superparamagnetic nanoparticles are used to reduce antenna size, then the antenna can be miniaturized, but dispersibility in resin is insufficient and manufacturing becomes difficult
Solution Approach 1:
The patent changes the particle size parameter from nanometer scale to 0.1-10 μm range. This size optimization provides sufficient wavelength shortening effect for antenna miniaturization while dramatically improving dispersibility in resin matrices and handling properties for mass production.
4Loss of energy
If W-type hexagonal ferrite is used in composite magnetic material, then magnetic loss and dielectric loss at high frequencies are reduced, but permeability becomes relatively small limiting further size reduction
Solution Approach 1:
The patent merges W-type hexagonal ferrite with M-type hexagonal ferrite and ferrite particles in a composite structure. This combination allows the W-type component to reduce magnetic loss while the M-type component and ferrite particles provide sufficient permeability for wavelength shortening and antenna size reduction.
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 magnetic material achieves superior bandwidth and efficiency at high frequencies, enabling a smaller antenna size with improved handling properties and economical manufacturing, suitable for mass production.
Implementation Method 1
the wavelength λ of the electromagnetic wave (radio wave) that passes through the magnetic material is represented by λ∝1/√(μ′r×∈′r) (wavelength shortening effect). The factor μ′r used herein represents a real part of a complex relative permeability μr of a magnetic material
Implementation Method 2
a magnetic material for antennas, as well as to an antenna and a wireless communication device using the same... magnetic loss, limited frequency bands... which increases the real part of relative permeability and suppresses magnetic loss
Data Source
AI summary
A magnetic material for antennas including: an M-type hexagonal ferrite represented by the following general formula (1) as a main phase, MA.Fe12-x.MBx.O19 (wherein MA is at least one kind selected from the group consisting of Sr and Ba, MB is MC or MD, MC is at least one kind selected from the group consisting of Al, Cr, Sc and In, MD is an equivalent mixture of at least one kind selected from the group consisting of Ti, Sn and Zr and at least one kind selected from the group consisting of Ni, Zn, Mn, Mg, Cu and Co, X is a number from 1 to 5), and an average crystal particle diameter is equal to or greater than 5 μm.