RFID RFIC Module Coil Layout for Reduced Tag Coupling
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Solution Overview
Problem
Existing RFID tags with impedance matching circuits experience unwanted coupling between adjacent coils, leading to failure in reading multiple sheet-like or plate-like articles simultaneously due to interference between neighboring coils.
Innovation Solution
The design includes RFIC modules with impedance matching circuits featuring coils that are juxtaposed on a substrate, where the straight line passing through the center of gravity of each coil's opening is inclined differently, reducing unwanted coupling by ensuring distinct orientations and positions of the coils, thereby facilitating mutual independence even when tags are closely arranged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple RFID tags are arranged closely together for simultaneous reading, then reading efficiency is improved, but unwanted coupling between adjacent coils occurs causing reading failure
Solution Approach 1:
The patent applies asymmetry by configuring the coil openings in different orientations. Specifically, in a set of RFIC modules, at least one RFIC module has its coil opening oriented differently from others. This asymmetric arrangement breaks the symmetry of magnetic field coupling between adjacent tags, preventing unwanted coupling effects and enabling reliable simultaneous reading of multiple closely arranged RFID tags
2Ease of manufacture
If coil openings are aligned in the same direction for consistent tag design, then manufacturing is simplified, but adjacent tags interfere with each other due to unwanted coupling
Solution Approach 1:
The patent introduces asymmetry in coil opening orientation while maintaining manufacturing feasibility. By specifying that coil openings extend in different directions in different RFIC modules within a set, the design achieves both manufacturing simplicity (standardized module structure) and interference prevention (different orientations). This resolves the contradiction between ease of manufacture and reduction of unwanted coupling
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 effectively suppresses unwanted coupling between adjacent RFIC modules, allowing for reliable reading of multiple RFID tags in close proximity, increasing the probability of successful tag reading from 2/16 to 14/16 when tags are stacked and aligned properly.
Implementation Method 1
an impedance matching circuit that is connected to the RFIC connection first electrode and the RFIC connection second electrode, and the antenna connection first electrode and the antenna connection second electrode, and matches impedance between the RFIC and an antenna
Implementation Method 2
an unwanted coupling between neighboring coils of the impedance matching circuits of the RFID tags might occur
Data Source
AI summary
RFID tag RFIC modules are provided with each module including an RFIC, an antenna connection first electrode, an antenna connection second electrode, an RFIC connection first electrode, an RFIC connection second electrode, an impedance matching circuit that matches impedance between the RFIC and an antenna, and a rectangular substrate. A first coil and a second coil of the impedance matching circuit are juxtaposed in/on the substrate, and a straight line passing through center of gravity of the coil opening of the first coil and center of gravity of the coil opening of the second coil is inclined with respect to one side of the substrate, and directions of this inclination are different between the first RFIC module and the second RFIC module.