Multilayer Substrate Coil Antenna Magnetic Shielding
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Solution Overview
Problem
Conventional surface mount coil antennas in HF band communication systems face limitations due to reduced magnetic flux interlinking and coupling coefficients when mounted on wiring substrates, leading to degraded communication characteristics and limited arrangement flexibility due to nearby electronic components and metal members.
Innovation Solution
A multilayer substrate design featuring a coil antenna with a winding axis along the lamination direction, a magnetic member, and a flexible second region that allows for increased arrangement freedom and magnetic shielding, reducing unnecessary coupling and radiation, and enabling effective magnetic flux distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the antenna device is mounted on the main surface of a wiring substrate, then the antenna device can be easily installed and connected, but magnetic flux interlinking with the coil antenna is disturbed by nearby electronic components and structures, reducing communication characteristics
Solution Approach 1:
The patent transitions the coil antenna from a planar configuration on the wiring substrate surface to a three-dimensional structure extending in the thickness direction. The winding axis of the coil antenna is oriented substantially perpendicular to the main surface of the wiring substrate, allowing the antenna to occupy the space between the wiring substrate and the cover member rather than being confined to the substrate surface. This dimensional change eliminates interference from planar electronic components while maintaining easy installation through the lamination structure.
2Adaptability or versatility
If the antenna device is mounted on the main surface of a wiring substrate, then the antenna device can be easily integrated into the device, but metal members such as conductor patterns or ground conductors in contact with the wiring substrate may unnecessarily couple with the coil antenna, decreasing the coupling coefficient with the communication partner's antenna
Solution Approach 1:
The patent introduces a magnetic member positioned between the coil antenna and the wiring substrate as an intermediary element. This magnetic member with high magnetic permeability serves multiple functions: it provides a magnetic flux path that concentrates and directs the magnetic field generated by the coil antenna, prevents unnecessary coupling between the coil antenna and metal members on the wiring substrate, and enhances the coupling coefficient with the communication partner's antenna. The magnetic member acts as a mediator that improves magnetic flux distribution while isolating the coil antenna from interfering electromagnetic fields.
3Reliability
If the coil antenna is positioned away from other electronic components to avoid magnetic flux disturbance, then communication characteristics are improved, but the degree of freedom in arrangement of the antenna device is reduced
Solution Approach 1:
The patent resolves the arrangement flexibility issue by utilizing the thickness direction (z-axis) as an additional dimension for antenna placement. Instead of requiring lateral separation from other components in the x-y plane, the coil antenna is positioned vertically between the wiring substrate and the cover member. This allows the antenna to coexist with other planar electronic components without magnetic flux interference, as the interfering components are separated in the thickness direction rather than in the plane. The winding axis is oriented substantially perpendicular to the main surface, enabling the antenna to occupy vertical space that would otherwise be unused.
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 design enhances communication characteristics by minimizing coupling with nearby components and substrates, increasing the degree of freedom in antenna arrangement, and improving magnetic flux interlinking, thereby reducing communication distance limitations.
Implementation Method 1
a magnetic member, and a flexible second region that allows for increased arrangement freedom and magnetic shielding, reducing unnecessary coupling and radiation, and enabling effective magnetic flux distribution
Implementation Method 2
a plurality of insulating base materials that are flexible and laminated thereon
Data Source
AI summary
A multilayer substrate, in which flexible insulating base materials are laminated, includes first and second regions. The number of laminated insulating base materials in the second region is smaller than that in the first region. The multilayer substrate includes a coil antenna located in the first region, a magnetic member located in the first region, a mounting component located in the first region, a wiring pattern, and an external connection terminal. The mounting component entirely overlaps the magnetic member when viewed in a thickness direction and is located on a side opposite to the coil antenna across the magnetic member in the thickness direction. At least a portion of the coil antenna overlaps the magnetic member when viewed in the thickness direction.