Foldable RFID Label Structure for Curved Metal and Liquid Containers

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Solution Overview

Problem

Existing RFID tags for metallic surfaces and liquid-filled containers in the UHF frequency range face challenges such as reduced read range due to signal disruption, high cost, inflexibility, and environmental impact, with current methods being complex and costly.

Innovation Solution

A flexible RFID tag design featuring a layered structure with a self-adhesive, foldable secondary antenna decoupled from the metallic surface via electromagnetic coupling, using environmentally friendly materials and a modular production process that includes punching, laminating, and folding steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the RFID tag is applied directly to metallic surfaces or liquid-filled containers, then the manufacturing process is simplified, but the read range is reduced due to signal disruption

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidread range
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces an intermediate layer structure between the RFID antenna and the metallic surface/liquid, consisting of a dielectric layer and an adhesive layer. This intermediary structure prevents direct contact between the antenna and the conductive surface or liquid, thereby reducing signal disruption while maintaining manufacturing simplicity. The dielectric layer acts as a buffer that isolates the electromagnetic field from the conductive environment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If traditional rigid OM tags are used on curved surfaces, then the manufacturing process is straightforward, but the tags experience stress and detachment due to inflexibility

Engineering Contradiction:
Improvemanufacturing process straightforwardnessVSAvoidtag adhesion stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent employs flexible thin film structures for the RFID tag components, including the dielectric layer and adhesive layer, which can conform to curved surfaces without experiencing excessive stress. The flexible nature of these thin films allows the tag to maintain its structural integrity and adhesion stability when applied to curved metallic surfaces, preventing detachment while keeping the manufacturing process straightforward.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If thick foam layers are used to create distance from metallic surfaces, then signal disruption is reduced, but the tag thickness increases beyond standard printer capabilities

Engineering Contradiction:
Improvesignal qualityVSAvoidtag thickness
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent optimizes the thickness parameters of the dielectric layer and adhesive layer to achieve the right balance between signal quality and tag thickness. By carefully controlling the thickness of these layers (making them thinner than traditional foam layers but sufficient to provide isolation), the patent reduces signal disruption while keeping the overall tag thickness within the capabilities of standard thermal transfer printers.

Inventive Principle:
Principle #35Parameter changes

4Object-affected harmful factors

If environmentally friendly materials are used, then environmental impact is reduced, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveenvironmental impactVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses composite material structures where environmentally friendly materials (such as biodegradable adhesives and eco-friendly dielectric materials) are combined in a layered configuration. This composite approach allows the use of sustainable materials while maintaining a relatively simple manufacturing process through lamination techniques, avoiding excessive complexity despite the environmental focus.

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 cost-effective, flexible RFID tag that maintains reading range on both flat and curved surfaces without stress, reduces manufacturing complexity, and improves print quality, while being environmentally friendly.

Implementation Method 1

a self-adhesive, foldable secondary antenna decoupled from the metallic surface via electromagnetic coupling

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Data Source

PatentEP4211608B1RFID label
Publication Date: 2026.02.18 ETIFIX
  • EP4211608B1 patent drawingFigure 1
  • EP4211608B1 patent drawingFigure 2
  • EP4211608B1 patent drawingFigure 3

AI summary

The invention relates to a method for producing an RFID label for use in particular on curved metal surfaces and on containers filled with liquids in the frequency range 860-960 MHz, having a substrate on which are arranged an electronic storage and transmission device designed as a microchip, a primary antenna galvanically connected to the microchip and a secondary antenna coupled to the primary antenna, wherein the substrate is designed as a continuous strip in roll form that can be processed by machine with a plurality of secondary antennas arranged thereon, a first variant being characterised by the following steps: - punching the secondary antenna out of a conductive metal layer, preferably a self-adhesive aluminium foil, and covering the secondary antenna with a preferably transparent self-adhesive film, in particular a polypropylene or polyethylene film; - punching a web out of a self-adhesive foam film; - applying the primary antenna to the covered secondary antenna at a position intended therefor and laminating a self-adhesive top material onto a partial region of the upper side of the covered secondary antenna; and - applying an adhesive to a partial region of the upper side of the covered secondary antenna, laminating the unit consisting of the primary and secondary antennas onto the self-adhesive foam film and punching out the RFID label intended for subsequent folding.