Antenna Device With Cavity-Embedded Sintered Magnetic Core
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Solution Overview
Problem
Existing antenna devices with multilayer structures face challenges in achieving complete sintering of magnetic substances due to temperature limitations, resulting in suboptimal material characteristics and antenna performance.
Innovation Solution
A resin multilayer substrate with a cavity housing a sintered magnetic substance, where the coil conductor is wound around the cavity, allowing for complete sintering of the magnetic substance and enhancing its permeability and low magnetic loss characteristics, while also providing positional flexibility and resistance to breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a multilayer structure with magnetic filler mixed with binder is used, then space is saved and coil conductor can be arranged over circuit board, but magnetic substance cannot be completely sintered due to temperature limitation
Solution Approach 1:
The patent divides the antenna device into separate components: the magnetic substance is placed in a cavity within the resin multilayer substrate, while the coil conductor is formed separately on the substrate. This segmentation allows the magnetic substance to be positioned without requiring high-temperature co-firing with the coil conductor, enabling complete sintering while maintaining the compact multilayer structure.
Solution Approach 2:
The resin multilayer substrate acts as an intermediary that holds the sintered magnetic substance in its cavity and provides a separate formation process for the coil conductor. This intermediary structure allows the magnetic substance to be sintered at high temperature independently, then assembled with the coil conductor at lower temperatures, resolving the temperature conflict.
2Manufacturing precision
If firing temperature is set to 900°C or higher for complete sintering of magnetic substance, then material characteristics improve, but silver electrode cannot withstand the temperature
Solution Approach 1:
The patent separates the magnetic substance from the coil conductor and circuit board, placing the magnetic substance in a cavity within the resin substrate. This allows the magnetic substance to be sintered at high temperatures (1000°C or higher) independently, while the silver electrode and other temperature-sensitive components remain on the resin substrate that is processed at lower temperatures.
Solution Approach 2:
The resin multilayer substrate serves as an intermediary structure that enables the magnetic substance to achieve complete sintering at high temperatures while protecting the silver electrode and other components from excessive heat. The cavity structure in the substrate provides a protected environment for the magnetic substance during assembly.
3Ease of manufacture
If magnetic filler is mixed with binder to form sheet, then manufacturing is simplified, but magnetic loss characteristic deteriorates
Solution Approach 1:
The patent extracts the magnetic substance from the binder mixture and places it as a separate sintered body in a cavity within the resin substrate. This eliminates the need for binder materials that cause magnetic loss, while maintaining ease of manufacture through the cavity structure that guides placement of the sintered magnetic substance.
Solution Approach 2:
The resin multilayer substrate contains a cavity that provides a structured space for the magnetic substance. This cavity structure allows the magnetic substance to be positioned precisely without requiring binder materials, reducing magnetic loss while maintaining manufacturing simplicity through the pre-formed cavity design.
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
This configuration enables the use of magnetic substances with high permeability and low magnetic loss, resulting in improved antenna characteristics and increased maximum communicable distance in wireless communication devices.
Implementation Method 1
the magnetic substance is not sintered completely and cannot obtain a favorable material characteristic (a high permeability and a low magnetic loss characteristic)
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
In an antenna device, first linear portions of a coil conductor are located on a lower surface of a first resin sheet. Second linear portions of the coil conductor are located on an upper surface of a second resin sheet. Via conductors of the coil conductor are formed in the first and second resin sheets and intermediate resin sheets located between the first and second resin sheets. The via conductors connect a first end and a second end of the first linear portions and a first end and a second end of the second linear portions, respectively. The first and second linear portions and the via conductors define the coil conductor. Each of the intermediate resin sheets includes an aperture in the center portion thereof. The lamination of the apertures defines a cavity in which a magnetic substance core is embedded. The coil conductor is wound around a periphery of the cavity.