Multi-layer Impedance Matching Circuit for Wireless IC
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Solution Overview
Problem
Existing wireless communication devices in RFID systems face challenges in impedance matching due to varying antenna shapes and environments, leading to increased impedance shifts and communication losses, particularly when impedance matching circuits are fabricated on the same base material as the antenna, which requires multiple substrate designs and complicates production and stock management.
Innovation Solution
A wireless communication device with an impedance matching circuit disposed on a multi-layer substrate or rewiring layer connected to the wireless IC chip, featuring multi-layer coil electric conductors and terminal electrodes, allowing for adjustable impedance settings by selecting connection positions, thereby minimizing environmental influences and enabling diverse impedance values for various antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the impedance matching circuit is fabricated on the same base material film as the antenna element, then the device complexity is reduced, but the impedance shifts and loss increase due to environmental influences
Solution Approach 1:
The patent divides the impedance matching circuit into multiple independent layers (first through fourth coil patterns in different layers) rather than fabricating it on the same base material as the antenna. This segmentation allows each layer to be optimized independently and reduces environmental interference, resolving the contradiction between device simplicity and impedance stability.
Solution Approach 2:
The patent transitions from a two-dimensional planar configuration to a three-dimensional multi-layer structure by stacking coil patterns across multiple layers. This dimensional change enables the impedance matching circuit to achieve better performance while maintaining reasonable device complexity through vertical integration.
2Reliability
If the impedance matching circuit is incorporated in a multi-layer substrate other than the antenna film, then the impedance stability improves, but the number of line-ups of multi-layer substrate increases resulting in increased labor for designing and stock management
Solution Approach 1:
The patent creates a universal multi-layer substrate structure that can accommodate various antenna types and impedance requirements through a standardized four-layer configuration. This universal design reduces the number of different substrate line-ups needed, thereby decreasing designing and stock management labor while maintaining impedance stability.
Solution Approach 2:
The patent achieves different impedance values by changing the connection positions between terminal electrodes and coil patterns, rather than creating entirely different substrate designs. This parameter-based adjustment allows a single multi-layer substrate structure to serve multiple impedance requirements, reducing manufacturing complexity.
3Device complexity
If the impedance matching circuit is configured using a rewiring layer of the wireless IC chip, then the device complexity is reduced, but the wireless IC chip cannot be used for any other use increasing difficulty for production and stock management
Solution Approach 1:
The patent extracts the impedance matching circuit from the wireless IC chip's rewiring layer and places it in a separate multi-layer substrate. This extraction allows the wireless IC chip to be reused for different applications while the impedance matching function is provided by the reusable substrate, resolving the contradiction between device simplicity and chip versatility.
Data Source
AI summary
In a wireless communication device, an impedance matching circuit includes a first layered coil conductor one end of which is connected to a first I/O terminal, the first layered coil conductor includes loop conductors including a plurality of layers, and a second layered coil conductor one end of which is connected to the other end of the first layered coil conductor and the other end of which is respectively connected to a second I/O terminal, the second layered coil conductor includes loop conductors including a plurality of layers. On the surface of the wireless communication device, first and second terminal electrodes are connected via first and second in-plane conductors and first and second inter-layer conductors to any of the loop conductors of the first and second layered coil conductors. Connection locations of the first and second in-plane conductors to the first and second layered conductors determine the antenna element-side impedance seen by the first and second I/O terminals of the wireless IC chip.