RFID Tag Coil Transformer Layout for Durable Rubber Tracking
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Solution Overview
Problem
RFID tags attached to tires or other rubber products face issues such as damage from tire deformation, impedance changes due to carbon black, and challenges in compact design and durability.
Innovation Solution
The RFID tag design incorporates a coupling transformer with a coil section, first and second antenna elements, and a printed circuit board, which forms a compact and durable configuration resistant to deformation and impedance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional half-wave dipole antenna is used, then the antenna can provide basic RFID communication, but the antenna size becomes large
Solution Approach 1:
The antenna is nested within the tire structure by utilizing the tire's conductive carcass ply cord as part of the antenna system. The antenna elements are integrated into the tire's existing conductive layers, allowing the antenna to function while maintaining a compact form factor that matches the tire's geometry.
Solution Approach 2:
The patent transitions from a traditional linear dipole antenna to a planar antenna structure that utilizes the two-dimensional surface of the tire. By arranging antenna elements in a plane and using the tire's conductive layers, the design achieves compactness while maintaining communication functionality.
2Length of moving object
If a meander line antenna is used to reduce size, then the antenna becomes more compact, but determining the effective meander length becomes difficult due to carbon black effects
Solution Approach 1:
The patent introduces a coupling transformer as an intermediary component between the antenna elements and the RFID chip. This transformer provides impedance matching and signal coupling while isolating the antenna design from the complexities of carbon black interference, making the design process more manageable.
Solution Approach 2:
The patent changes the electrical parameters of the antenna system by using the tire's conductive carcass ply cord with specific resistance characteristics. By selecting and utilizing materials with appropriate electrical properties, the design achieves reliable performance without requiring complex meander line calculations.
3Reliability
If the second antenna is provided with extensions to the left and right from the electromagnetic coupling section, then electromagnetic coupling is achieved, but the extensions are pulled apart when the tire deforms, causing damage
Solution Approach 1:
The patent creates a dynamic antenna structure where the conductive carcass ply cord can flex and deform with the tire while maintaining electrical continuity. The antenna elements are arranged to accommodate tire deformation, allowing the structure to move dynamically without breaking electrical connections.
Solution Approach 2:
The patent merges the antenna structure with the tire's structural components, specifically the conductive carcass ply cord. By combining the antenna function with the tire's existing conductive framework, the design eliminates separate extensions that would be vulnerable to deformation damage.
4Reliability
If the first antenna and second antenna are electromagnetically coupled with high signal source impedance, then coupling is achieved, but the configuration becomes susceptible to impedance and relative permittivity changes due to carbon black
Solution Approach 1:
The coupling transformer serves as an intermediary that provides impedance matching between the antenna elements and the RFID chip. This intermediary component stabilizes the impedance relationship, reducing the system's susceptibility to variations caused by carbon black and other environmental factors.
Solution Approach 2:
The patent optimizes the electrical parameters of the antenna system by adjusting the number of windings in the coupling transformer and selecting appropriate conductor materials. By carefully controlling these parameters, the design achieves stable impedance characteristics that are less sensitive to external variations.
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 design enhances the mass productivity and durability of RFID tags for rubber products, maintaining communication performance even in the presence of carbon black, and allows for a more compact size compared to conventional antennas.
Implementation Method 1
the coil section forms a primary side of a coupling transformer
Implementation Method 2
the free electrons of the carbon black in the tire undergo a charge shift from negative to positive when exposed to radio waves, which causes the current to flow from positive to negative, which in turn causes the impedance and the relative permittivity to change
Data Source
AI summary
An RFID tag 1 for a rubber product is provided with a coupling transformer 40, an RF chip 10 connected to a secondary side of the coupling transformer, a printed circuit board 20 on which the RF chip is mounted, and an antenna 30, wherein the antenna comprises a coil section 31, a first element 32 extending from one end of the coil section, and a second element 33 extending from another end of the coil section in parallel with the first element and shorter than the first element, the coil section has fewer windings than the coupling transformer 40 on the secondary side, and the printed circuit board 20 is held in a gap between strands of the coil section such that the coil section forms a primary side of the coupling transformer.