RFID Label Frequency Pre-tuning for Curved Surfaces

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Solution Overview

Problem

Planar-shaped EAS and RFID labels experience performance degradation when adhered to curved surfaces due to changes in resonant frequency and inductance, reducing detectable distance or disabling their function.

Innovation Solution

A method of frequency pre-tuning involves obtaining measurements to determine the subtending angle and estimating the pre-tuned resonant frequency by subtracting the change in resonant frequency caused by surface curvature, ensuring the label's resonant frequency matches the electromagnetic field frequency when applied to curved surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a planar-shaped EAS or RFID label is adhered to a curved surface, then the label can be applied to curved surfaces, but the resonant frequency changes and inductance alters, reducing detectable distance or disabling label function

Engineering Contradiction:

Improveability to apply label to curved surfacesVSAvoidlabel detection function

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-tuning the resonant frequency of the label during manufacturing to account for the frequency shift that will occur when the label is bent onto a curved surface. The label is designed with a initial resonant frequency that is offset from the target frequency by an amount equal to the expected shift due to curvature, so that when bent, the frequency naturally settles at the correct operating frequency for reliable detection

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the label is bent to accommodate curved surface, then the label can be applied to the surface, but the inductance of the electronic circuit changes, reducing detectable distance

Engineering Contradiction:

Improveability to conform to curved surfaceVSAvoiddetectable distance

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The patent applies parameter changes by modifying the electrical parameters of the label circuit during design and manufacturing. Specifically, the inductance and capacitance values are adjusted to compensate for the change in inductance that occurs when the label is bent. This may involve selecting different component values or adjusting trace geometry in the PCB to offset the expected inductance increase from bending, thereby maintaining the detectable distance

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the resonant frequency is adjusted for curved surfaces, then the label maintains detection function on curved surfaces, but additional frequency tuning steps are required

Engineering Contradiction:

Improvelabel detection function on curved surfacesVSAvoidfrequency tuning process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent resolves this contradiction by performing the frequency tuning action in advance during the manufacturing process rather than requiring field adjustment. The label is pre-tuned at the factory with the correct frequency compensation built in, so that when deployed on curved surfaces, no additional tuning steps are needed by the end user. This transfers the complexity to the manufacturing stage while simplifying deployment

Inventive Principle:

Principle #10Preliminary action

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 method allows EAS and RFID labels to maintain effective performance on curved surfaces by compensating for curvature effects, ensuring consistent detection and energization by EAS or RFID systems.

Implementation Method 1

The electronic circuit is designed to energize itself in the electromagnetic field excited at the resonant frequency determined by the electromagnetic characteristics of the circuit

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

bending the label to accommodate the curved surface of the item alters the label's electromagnetic characteristics, including the resonant frequency and the inductance of the electronic circuit

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentUS10832114B1Method of frequency pre-tuning of EAS and RFID labels for curved surfaces

Publication Date: 2020.11.10 IM BONG JIM

AI summary

A method of compensating for curvature effects to resonant frequency on pre-tuned planar-shaped EAS and RFID labels to apply to curve surfaces of Items. The method comprises obtaining width measurements of planar-shaped labels and radius measurements of Objects having curved external surfaces to which to apply the labels, and determines a subtending angle of a labels when applied to a curved external surface of an objects based on a quotient result of dividing the width measurement of a label along a perimeter of a curved external surface of the object and the radius measurement of the object.