RFID Tag Coil Layout to Prevent Magnetic Flux Cancellation
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Solution Overview
Problem
The communication distance of RFID tags is shortened due to magnetic flux cancellation caused by the opposing directions of connection conductors and the coil conductor in existing RFID tag designs.
Innovation Solution
The RFID tag design includes a coil conductor with overlapping first and second connection conductors that electrically connect the RFIC chip and spiral conductors on opposite surfaces of a base material, ensuring the RFIC chip is positioned in the coil conductor's opening, thereby preventing magnetic flux cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first connection conductor and the second connection conductor extend in opposite directions from the RFIC chip, then the electrical connection between the coil conductor and the RFIC chip is established, but the magnetic flux generated by current flowing through these conductors cancels each other out, shortening the communication distance
Solution Approach 1:
The patent transitions from a planar two-dimensional layout where connection conductors extend in opposite directions to a three-dimensional configuration where the first connection conductor extends in a first direction and the second connection conductor extends in a second direction that is not opposite to the first direction. This spatial reconfiguration in multiple dimensions prevents magnetic flux cancellation while maintaining electrical connectivity, thereby resolving the contradiction between connection reliability and communication distance.
Solution Approach 2:
The patent employs asymmetric arrangement of the connection conductors, where the first connection conductor and the second connection conductor extend in different directions rather than symmetric opposite directions. This asymmetric configuration disrupts the magnetic flux cancellation effect that occurs with symmetric opposite-direction extensions, allowing the magnetic flux to effectively extend in the direction from the coil conductor toward the RFID reader, thus improving communication distance while maintaining reliable electrical connection.
2Productivity
If the RFIC chip is disposed in the opening of the coil conductor, then the communication efficiency is improved, but the magnetic flux cancellation effect occurs due to the current path through the connection conductors
Solution Approach 1:
Instead of allowing the connection conductors to extend in opposite directions which causes magnetic flux cancellation, the patent inverts the approach by extending the first connection conductor in a first direction and the second connection conductor in a second direction that is not opposite to the first direction. This inverted configuration prevents the harmful magnetic flux cancellation while preserving the beneficial positioning of the RFIC chip in the coil conductor opening, thereby maintaining communication efficiency without energy loss.
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 maintains or enhances communication distance while ensuring stable electrical connections and prevents tilting of the RFIC chip during attachment, thus improving communication efficiency.
Implementation Method 1
a magnetic flux generated by current flowing through the first connection conductor, the RFIC chip, and the second connection conductor, as well as part of a magnetic flux generated by current flowing through the coil conductor
Data Source
AI summary
An RFID tag is provided that includes a base material that includes a first and second surfaces, a coil conductor that includes first and second spiral conductors provided on the first and second surfaces of the base material, respectively, an RFIC chip provided on the base material such that the RFIC chip is positioned in an opening of the coil conductor in plan view of the base material, and first and second connection conductors provided on the first and second surfaces of the base material, respectively. The first and second connection conductors electrically connect first and second spiral conductors and the RFIC chip. Moreover, the first connection conductor and the second connection conductor at least partially overlap each other in the plan view of the base material.