RFID Tag Testing with Hybrid Coupler Phase Control

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Solution Overview

Problem

Existing RFID testing methods for far-field transponders on production lines face challenges such as inaccuracy, complexity, and slowness, particularly in focusing the far field for individual transponders, leading to inefficient on-line performance testing and increased engineering costs.

Innovation Solution

A system utilizing two electrodes with a hybrid coupler to create a phase-differentiated electric field for capacitive coupling with RFID tags, allowing for efficient frequency response testing with minimal interference from nearby transponders and robustness against position variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If far field testing is performed on production lines with closely spaced transponders, then on-line performance testing can be conducted, but the far field cannot be easily focused to an individual transponder causing measurement interference from surrounding transponders

Engineering Contradiction:
Improveon-line testing capabilityVSAvoidfrequency response accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent divides the measurement space by introducing a partitioned measuring chamber that isolates the individual transponder being tested from surrounding transponders. This segmentation allows far field focusing on a single transponder while preventing interference from neighboring transponders on the production line, thereby enabling both on-line testing and accurate frequency response measurement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary measuring chamber with partitions that acts as a mediator between the transponder and the testing environment. This intermediary structure creates a controlled measurement zone where far field can be properly focused while blocking interference from surrounding transponders, resolving the contradiction between on-line testing capability and measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If screening structures are designed to isolate individual transponders for far field detection, then measurement accuracy improves, but additional engineering work and device complexity increase

Engineering Contradiction:
Improvefrequency response accuracyVSAvoidscreening structure design
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent designs a universal partitioned measuring chamber that can accommodate different types of transponders without requiring custom screening structures for each type. The standardized chamber design with adjustable partitions provides a multi-functional solution that maintains measurement precision while reducing the engineering work and complexity associated with designing separate screening structures for each transponder type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs adjustable partitions within the measuring chamber that can be configured to optimize the measurement space for different transponder types and sizes. By changing the physical parameters of the measurement environment through adjustable partitions rather than redesigning entire screening structures, the system maintains high measurement precision while minimizing device complexity and engineering effort.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional testing methods are used to maintain production speed, then productivity is preserved, but testing accuracy and robustness against position variations deteriorate

Engineering Contradiction:
Improveproduction speedVSAvoidtesting robustness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements preliminary positioning guides and alignment mechanisms that ensure the transponder is correctly positioned within the partitioned measuring chamber before testing begins. This preliminary action eliminates the need for repeated testing due to position variations, thereby maintaining production speed while significantly improving testing reliability and robustness against positioning errors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent incorporates feedback mechanisms that monitor the transponder's position and performance during testing. If position variations are detected, the system provides feedback to adjust the measurement parameters or reposition the transponder, ensuring accurate frequency response measurement without requiring slow manual intervention. This feedback loop maintains both productivity and testing reliability.

Inventive Principle:
Principle #23Feedback

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 provides accurate and reliable frequency response testing with high coupling efficiency, reducing the impact of tag position and production line speed variations, enabling comprehensive and efficient on-line testing of RFID transponders.

Implementation Method 1

at least two electrodes creating an electric field between them that capacitively couples to the tag placed in the reading zone

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

a hybrid coupler for causing a phase difference between the excitation signals fed to the at least two electrodes from the communication terminal

Methodology Applied
Scientific EffectPhase difference:

Implementation Method 3

a hybrid coupler for causing a phase difference between the excitation signals fed to the at least two electrodes from the communication terminal and for combining the response signals from the at least two electrodes at the communication terminal

Methodology Applied
Scientific EffectSignal combining:

Data Source

PatentEP2834773B1Method for testing radio-frequency tags
Publication Date: 2017.11.29 VOYANTIC OY
  • EP2834773B1 patent drawingFigure 1~2
  • EP2834773B1 patent drawingFigure 3
  • EP2834773B1 patent drawingFigure 4A~4B

AI summary

The invention relates to a system and method for testing radio-frequency tags(18). The system comprises a reading zone (17) for a radio-frequency tag and at least two electrodes (11A,11B) for capacitively coupling to the tag placed in the reading zone. According to the invention,the system further comprises a communication terminal (14) connected to each of the at least two electrodes for feeding signals to the electrodes and for reading tag response signals from the electrodes, and a hybrid coupler(13) for causing a phase difference between the excitation signals fed to the at least two electrodes from the communication terminal and for combining the response signals from the at least two electrodes at the communication terminal(14). The invention allows for efficient coupling to tags in near field and relieves the tag positioning requirements during testing.