Textile RFID Tag with Double Loop Antenna

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Solution Overview

Problem

Current RFID tags used in harsh environments, such as industrial laundries, face issues with mechanical and thermal mismatches between metallic UHF antennas and textile substrates, leading to detachment, oxidation, and unsightly stains, while being too large for small items and lacking flexibility.

Innovation Solution

The use of electroconductive stainless steel yarn for the UHF-SHF antenna, allowing for flexible and discreet designs with innovative geometries like double loops for efficient inductive coupling, and embedding the transponder in a textile substrate to match mechanical and thermal properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metallic wire UHF antenna is used, then electromagnetic performance is improved, but the antenna oxidizes in contact with water and chemicals, affecting electrical parameters and electromagnetic performance

Engineering Contradiction:
Improveelectromagnetic performanceVSAvoidoxidation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional metallic wire antenna with an electroconductive thread antenna that is specifically designed to resist oxidation from water and chemicals. This substitution eliminates the harmful oxidation effect while maintaining electromagnetic functionality, allowing the antenna to withstand harsh laundry environment conditions.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses an electroconductive thread as a composite material that combines the electrical conductivity needed for antenna function with resistance to oxidation from water and chemicals. This composite material approach resolves the contradiction by providing both electromagnetic performance and chemical stability.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a metallic wire antenna is used, then electromagnetic performance is improved, but the tag becomes rigid and creates break lines on the RFID tagline

Engineering Contradiction:
Improveelectromagnetic performanceVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the physical parameters of the antenna material from rigid metallic wire to flexible electroconductive thread. This parameter change maintains electrical conductivity and electromagnetic performance while dramatically improving flexibility and eliminating the rigidity that causes break lines on the RFID tagline.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a flexible electroconductive thread instead of rigid metal wire, allowing the antenna to bend and flex without creating break lines. This flexible construction maintains electromagnetic functionality while adapting to the flexible nature of textile materials.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If a metallic wire antenna is used, then electromagnetic performance is improved, but the tag size becomes large and inappropriate for small items

Engineering Contradiction:
Improveelectromagnetic performanceVSAvoidtag size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent uses a loop geometry for the electroconductive thread antenna, creating a compact curved structure that provides efficient electromagnetic coupling. This loop design achieves good electromagnetic performance in a much smaller form factor compared to traditional linear or spiral metallic antennas.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the antenna geometry and material properties to achieve compact dimensions. The electroconductive thread allows for tighter winding and smaller loop dimensions while maintaining electrical performance, making the tag suitable for small items like tablecloths.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If a metallic wire antenna is used, then electromagnetic performance is improved, but the antenna stores much more thermal energy than the textile support, leading to piercing of the textile material

Engineering Contradiction:
Improveelectromagnetic performanceVSAvoidthermal energy storage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the high thermal mass metallic wire with an electroconductive thread that has thermal properties matched to textile materials. This substitution eliminates the harmful thermal energy storage effect that causes piercing, while maintaining the necessary electrical conductivity for antenna operation.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses an electroconductive thread with thermal properties homogeneous to textile materials, rather than the dissimilar thermal properties of metal wire. This homogeneity prevents the thermal energy storage discrepancy that leads to textile piercing, while maintaining electromagnetic functionality.

Inventive Principle:
Principle #33Homogeneity

5Adaptability or versatility

If the RFID tag is made small for discreet identification, then adaptability to small items is improved, but electromagnetic performance may be compromised

Engineering Contradiction:
Improvesuitability for small itemsVSAvoidelectromagnetic performance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses a loop geometry for the electroconductive thread antenna that provides efficient electromagnetic coupling in a compact form. This curved loop structure achieves good electromagnetic performance despite the reduced size, making the tag suitable for small items while maintaining readability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent employs electroconductive thread as a composite material that enables compact antenna design without sacrificing electromagnetic performance. The unique properties of this material allow for smaller dimensions while maintaining the electrical characteristics needed for reliable RFID operation.

Inventive Principle:
Principle #40Composite materials

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 solution provides a flexible, resistant, and compact RFID tag with improved electromagnetic performance, capable of withstanding numerous washing cycles and maintaining identity without compromising the textile's appearance or integrity.

Implementation Method 1

an antenna (2) made of an electroconductive yarn, electrically insulated, embroidered on a textile substrate (1), having a loop geometry (5) through which an efficient inductive coupling with an RFID transponder (3) is provided

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3639204B1RFID tag for harsh environment inductively coupled in double loop
Publication Date: 2022.01.05 PROMAR TEXTIL INDUSTRIES SRL
  • EP3639204B1 patent drawingFigure 1~3

AI summary

The invention relates to an IDRF label for use in aggressive environments. The IDRF label (1) according to the invention comprises a UIF-SIF (2) antenna made of an electrically conductive textile, electrically insulated, embroidered on a textile backing, an IDRF transponder (3) and a textile substrate (4) and the UIF-SIF antenna (2), the whole assembly being sealed by hot-dipping a second textile substrate, wherein the UIF-SIF (2) antenna has a central loop formed by a loop (5) by which it inductively couples with the encapsulated IDRF transponder 3.