Antenna Device With Intersecting Power Feed Coils For NFC
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Solution Overview
Problem
Existing antenna devices for near field communication (NFC) systems have weak coupling strength between the power feed coil and the coil antenna, limiting their communication capabilities.
Innovation Solution
The antenna device includes a power feed coil with a first and second power feed coil, where the second coil has a planar configuration and the coil antenna also has a planar configuration, aligned parallel to the second power feed coil, with the first power feed coil's winding axis intersecting the coil antenna's axis, enhancing magnetic flux pickup and coupling strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If both the first coil antenna and the second coil antenna are coupled to the booster coil antenna only by magnetic fields around vicinities of corners of the booster coil antenna, then the device complexity is reduced, but the coupling strength between the power feed coil and the booster coil antenna becomes weak
Solution Approach 1:
The power feed coil is divided into two separate coils: the first power feed coil and the second power feed coil. The first power feed coil is coupled to the booster coil antenna at the first end, while the second power feed coil is coupled to the booster coil antenna at the second end. This segmentation allows magnetic flux to be picked up from both ends of the booster coil antenna, thereby increasing the overall coupling strength without significantly increasing device complexity
Solution Approach 2:
The first power feed coil and the second power feed coil are arranged in different spatial dimensions relative to the booster coil antenna. The winding axis direction of the first power feed coil crosses the winding axis direction of the booster coil antenna, while the second power feed coil is arranged with its winding axis substantially parallel to the booster coil antenna's winding axis. This multi-dimensional arrangement maximizes magnetic flux pickup from different orientations, enhancing coupling strength
2Reliability
If the winding axis direction of the first power feed coil crosses the winding axis direction of the coil antenna, then the magnetic flux pickup capability is improved, but the device complexity increases
Solution Approach 1:
Different portions of the power feed coil system are designed with different orientations to match the local magnetic field characteristics of the booster coil antenna. The first power feed coil at one end has its winding axis crossing the booster coil antenna's winding axis to capture magnetic flux in one orientation, while the second power feed coil at the other end has its winding axis substantially parallel to capture flux in another orientation. This local optimization of coil orientation enhances overall magnetic flux pickup capability
Solution Approach 2:
The first power feed coil and the second power feed coil are electrically connected in series to form a unified power feed system. By merging these two coils with different orientations into a single series-connected unit, the patent achieves both improved magnetic flux pickup capability from multiple orientations and reduced device complexity through unified electrical connection
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 increases the coupling strength between the power feed coils and the coil antenna, improving communication capabilities by widening the communicable range and angular range, and allowing for both magnetic and electrical coupling, thus enhancing communication efficiency.
Implementation Method 1
the first power feed coil picks up magnetic flux in a surface direction (lateral direction) of the coil antenna
Implementation Method 2
the second power feed coil picks up magnetic flux in a direction vertical to that surface (longitudinal direction)
Implementation Method 3
a coil antenna that electro-magnetically couples with the power feed coil
Data Source
AI summary
An antenna device includes a power feed coil to be connected to a RFIC and a coil antenna that couples with the power feed coil. The power feed coil includes a first power feed coil and a second power feed coil connected to the first power feed coil. The second power feed coil includes a coil opening with a planar or substantially planar shape. The coil antenna includes a coil opening with a planar or substantially planar shape along a plane identical, parallel, or substantially parallel to that of the coil opening of the second power feed coil. The center of gravity of the coil antenna is located within the coil opening of the second power feed coil when viewed in plan view. A winding axis direction of the first power feed coil crosses or intersects with a winding axis direction of the coil antenna. The first power feed coil and the second power feed coil magnetically couple with the coil antenna.