Multilayer Reactive RFID Strap for Compact Clothing Label Inductance
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Solution Overview
Problem
Conventional RFID devices incorporated into clothing labels or tags face durability and comfort issues due to stress from wear and handling, and their size can be noticeable, affecting user comfort.
Innovation Solution
The development of a multilayer reactive RFID strap with a first and second conductor portion forming a multiturn coil, which increases inductance within a smaller area, allowing for a smaller, more robust, and less noticeable RFID device that can be more comfortably integrated into clothing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a single-layer reactive strap is used, then the device structure is simple, but the inductance per area is insufficient and the device size is larger
Solution Approach 1:
The patent transitions from a single-layer reactive strap to a multi-layer configuration, adding the vertical dimension (z-axis) to the traditional planar (x-y plane) structure. Multiple conductor portions are stacked at different heights with dielectric layers between them, creating a three-dimensional inductance structure that increases inductance density without proportionally increasing the footprint area.
Solution Approach 2:
The reactive strap employs composite construction with conductor portions made of conductive material, dielectric layers providing insulation and mechanical support, and flexible substrate material enabling wearability. This composite structure achieves both high inductance density and mechanical flexibility required for clothing integration.
2Ease of operation
If the reactive strap area is reduced for comfort, then user comfort improves, but the inductance may be insufficient for proper RFID operation
Solution Approach 1:
The patent changes the inductance parameter by stacking multiple conductor portions vertically, each contributing to the total inductance. The inductance can be tuned by adjusting the number of layers, the area of each conductor portion, the spacing between layers, and the dielectric properties, allowing optimization for both small size and reliable RFID operation.
Solution Approach 2:
By utilizing the vertical dimension through multi-layer stacking, the patent achieves high inductance values in a compact footprint. This allows the reactive strap to maintain sufficient inductance for RFID operation while minimizing the horizontal area that contacts the user's skin.
3Reliability
If the reactive strap is made larger to increase inductance, then RFID performance improves, but the device becomes more noticeable and less comfortable
Solution Approach 1:
The patent resolves this contradiction by moving the inductance-generating structure into the vertical dimension through multi-layer stacking. This allows high inductance values necessary for reliable RFID performance to be achieved without increasing the horizontal footprint that would make the device noticeable or uncomfortable during wear.
4Ease of manufacture
If conventional single-layer reactive straps are used, then manufacturing is simple, but the device lacks robustness under stress from wear and handling
Solution Approach 1:
The multi-layer construction with dielectric layers and flexible substrate creates a composite structure that distributes mechanical stress across multiple layers and interfaces. This enhances the overall robustness and durability of the RFID device, allowing it to withstand washing, folding, and handling while maintaining electrical connectivity between layers.
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 multilayer reactive RFID strap provides improved durability and reduced size, enhancing user comfort and allowing for better coupling with antennas, while maintaining or exceeding the inductance of single-layer designs.
Implementation Method 1
reactive RFID strap with a first and second conductor portion forming a multiturn coil, which increases inductance within a smaller area
Data Source
AI summary
In some embodiments, an RFID device may include a multilayer reactive strap having a first substrate, a first conductor portion, a second conductor portion, and a first connection. The first conductor portion may enclose a first area and may be disposed on a first side of first substrate. A second conductor portion may enclose a second area and may be disposed on a second side of the first substrate. A first connection may couple the first conductor portion and the second conductor portion together, and may thereby form a multiturn coil that includes both the first conductor portion and the second conductor portion.