RFID Test System Near-Field Coupling Control

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Solution Overview

Problem

Existing RFID test systems face challenges in accurately testing RFID devices in close proximity due to interference from adjacent devices, leading to erroneous results and reduced manufacturing quality and yields, as conventional methods apply fixed thresholds that do not account for nearby device interactions.

Innovation Solution

An RFID test system that establishes a minimum coupling between ports without an RFID tag and increases coupling when a tag is present, using electric or magnetic near field transmit and receive elements, or a combination of both, to isolate adjacent tags and determine the peak frequency and coupling amplitude for accurate tag identification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If RFID devices are tested in close proximity to each other, then manufacturing productivity is improved, but test accuracy deteriorates due to interference from adjacent devices

Engineering Contradiction:
Improvemanufacturing productivityVSAvoidtest accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces a coupling control mechanism that acts as an intermediary between the test RFID device and adjacent devices. This mechanism dynamically adjusts the coupling strength to isolate the test device from interference while allowing efficient testing in close proximity, thereby maintaining both productivity and test accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs dynamic threshold adjustment based on the detected coupling environment. The test system continuously monitors interference levels and adapts the coupling thresholds in real-time, enabling accurate testing even when devices are closely spaced, thus resolving the contradiction between high-density testing and measurement precision

Inventive Principle:
Principle #15Dynamics

2Device complexity

If fixed thresholds are used for tag identification, then device complexity is reduced, but test reliability deteriorates due to interference from nearby devices

Engineering Contradiction:
Improvetest system complexityVSAvoidtest reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent performs preliminary coupling assessment before conducting the actual tag identification. By pre-evaluating the coupling environment and setting adaptive thresholds in advance, the system eliminates the need for complex real-time adjustments during testing, maintaining simplicity while improving reliability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent dynamically changes the coupling threshold parameter based on the detected interference level. Instead of using a single fixed threshold, the system adjusts this parameter adaptively, allowing reliable tag identification in varying electromagnetic environments without significantly increasing system complexity

Inventive Principle:
Principle #35Parameter changes

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 approach provides more accurate and reliable test results by isolating adjacent tags and determining the peak frequency and coupling amplitude, leading to improved manufacturing quality and yields by using adaptive thresholds and controlled coupling.

Implementation Method 1

an RFID test system that establishes a minimum coupling between two ports without an RFID tag present and a higher coupling when the RFID tag is present

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

uses electric or magnetic near field transmit and receive elements (components)

Methodology Applied
Scientific EffectNear field electromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP3532982B1Transmission RFID test systems
Publication Date: 2023.11.22 AVERY DENNISON RETAIL INFORMATION SERVICES LLC
  • EP3532982B1 patent drawingFigure 1A~1B
  • EP3532982B1 patent drawingFigure 2
  • EP3532982B1 patent drawingFigure 3

AI summary

An RFID test system is disclosed that establishes a minimum coupling between two ports without an RFID tag present and a higher coupling when the RFID tag is present. Furthermore, this controlled coupling in the presence of an RFID tag is used to read and identify tags. The RFID tag is read when it is in the coupling zone, as it receives maximum power and has the lowest loss path to the receiver. Adjacent tags do not couple efficiently, so they are isolated from the wanted device (i.e., RFID tag). Further, the coupling through the RFID tag can be frequency specific, and the peak frequency can be determined. This peak frequency and also the amount of coupling can give a good indication of a number of aspects of the tag assembly.