Multi-layer FPCB Spiral Antenna for Mobile Terminals
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Solution Overview
Problem
Near field communication antennas in mobile terminals face challenges in reducing antenna pattern width and maintaining performance due to space constraints and degradation when installed near metal or curved battery covers.
Innovation Solution
A multi-layer Flexible Printed Circuit Board (FPCB) with a spiral loop-shaped antenna pattern is integrated into the mobile terminal's window, eliminating the need for additional installation space and reducing antenna pattern width, while maintaining performance even with metal or curved battery covers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a single-layer conductive line is used to form antenna loops, then the antenna pattern width increases, but the device complexity is reduced
Solution Approach 1:
The patent transitions from a single-layer (2D) antenna structure to a multi-layer (3D) structure. By forming antenna patterns on multiple layers of the FPCB and connecting them through conductive vias, the antenna achieves the required loop area and electromagnetic performance with a reduced footprint width, directly resolving the contradiction between antenna pattern width and device complexity.
Solution Approach 2:
The patent implements nested antenna loops where multiple conductive lines are formed in parallel on the same layer, with some lines electrically connected through vias to create nested loop structures. This nesting approach increases the effective antenna area without proportionally increasing the outer dimensions, thereby reducing the antenna pattern width while maintaining functionality.
2Area of stationary object
If the near field communication antenna is installed on a metal or curved battery cover, then the installation area is reduced, but the antenna performance degrades
Solution Approach 1:
The patent utilizes the FPCB's inherent flexibility to conform to curved battery cover surfaces. The flexible circuit board can be bent and shaped to match the curvature of the battery cover, allowing the antenna to maintain its planar geometry and electromagnetic performance even on non-flat surfaces, thus resolving the contradiction between installation area and antenna performance.
Solution Approach 2:
The FPCB acts as an intermediary between the rigid antenna pattern and the curved battery cover surface. By mounting the antenna on the flexible circuit board rather than directly on the metal cover, the system decouples the antenna geometry from the surface curvature, preventing performance degradation while enabling installation on curved surfaces.
3Power
If multiple antenna loops are formed in a single layer, then the electromotive force is generated, but the antenna pattern width increases
Solution Approach 1:
The patent distributes antenna loops across multiple vertical layers of the FPCB instead of expanding them horizontally in a single layer. By stacking loops on different layers and connecting them through conductive vias, the system generates the required electromotive force through multiple loops while maintaining a compact antenna pattern width, directly resolving the contradiction between power generation and area occupation.
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 solution allows for reduced antenna pattern width and improved performance by laminating conductive lines across multiple layers on the FPCB, ensuring effective near field communication signals are transmitted without degrading due to metal or curved battery cover interference.
Implementation Method 1
This near field communication antenna device has an LC resonance loop antenna utilizing magnetic coupling to perform near field communications
Implementation Method 2
A multi-layer Flexible Printed Circuit Board (FPCB) on which a plurality of layers are laminated on a lower side of the black mark region of the window
Data Source
AI summary
A near field communication antenna device of a mobile terminal is provided. The near field communication antenna device includes a window including a display region for transmitting an image displayed by a display and a black mark region formed around the display region, a multi-layer Flexible Printed Circuit Board (FPCB) on which a plurality of layers are laminated on the lower side of the black mark region of the window, and a spiral loop-shaped antenna pattern in which conductive lines are formed on respective layers of the multi-layer FPCB and are connected to each other. Accordingly, a near field communication antenna is not disposed in a separated installation space, an antenna pattern width can be reduced, and performance of the near field communication antenna may be prevented from being degraded when a battery cover is made of metal or has a curved shape.