Multi-filler Helical Antenna for RFID Tag Access

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Solution Overview

Problem

The non-uniform electric field generated by patch antennas used for reading RFID tags leads to read and write errors, limiting the number of simultaneous operations to about 50 and requiring movement of sample containers to achieve stable access.

Innovation Solution

A tag access apparatus employing multi-filler helical antennas with a hybrid distributor and 90° phase shifter, connected to a reader/writer, generates a circular polarized wave to improve access accuracy and stability, allowing collective reading and writing from a large number of tags without moving the sample containers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a patch antenna is used for reading RFID tags, then the device structure is simple, but the electric field is non-uniform causing read/write errors and limiting simultaneous operations to about 50 tags

Engineering Contradiction:
Improveantenna structureVSAvoidreading and writing accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the antenna system into multiple helical antenna elements arranged in a specific geometric configuration. This segmentation allows each element to contribute to a more uniform overall electric field distribution, enabling reliable reading and writing of RFID tags without the limitations of a single patch antenna.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs helical antenna elements with curved three-dimensional structures instead of flat patch antennas. The helical geometry naturally generates a more isotropic and uniform electromagnetic field distribution in space, resolving the non-uniform electric field problem while maintaining structural simplicity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Device complexity

If a patch antenna is used, then the device structure is simple, but sample containers must be moved to achieve stable reading and writing

Engineering Contradiction:
Improveantenna structureVSAvoidcontainer movement requirement
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The helical antenna elements create a three-dimensional uniform electromagnetic field that envelops the sample containers, eliminating the need to move containers to specific positions. The curved helical structure radiates energy uniformly in multiple directions, allowing stable RFID access regardless of container position within the field region.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent transitions from a two-dimensional patch antenna to a three-dimensional helical antenna configuration. This dimensional change creates a volumetric electromagnetic field that uniformly covers the sample container placement area, eliminating position-dependent reading/writing issues and the need for container movement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If multiple RFID tags are accessed simultaneously, then productivity increases, but read/write errors increase due to non-uniform electric field

Engineering Contradiction:
Improvenumber of simultaneous operationsVSAvoidreading and writing accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent uses multiple helical antenna elements that collectively create a uniform electromagnetic field across a larger spatial volume. This segmented approach allows simultaneous access to many more RFID tags (exceeding 50 tags) while maintaining high reading and writing accuracy, as each tag experiences a uniform field regardless of its position in the array.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple helical antenna elements into a unified array system that produces a collectively uniform electromagnetic field. By merging the radiation patterns of individual helical elements, the system achieves both high productivity through simultaneous multi-tag access and high reliability through uniform field distribution across all tag positions.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances reading and writing accuracy, enabling access to multiple RFID tags without errors, reduces the need for container movement, and lowers operational costs by maintaining consistent electric field strength across the antenna surface.

Implementation Method 1

A tag access apparatus employing multi-filler helical antennas with a hybrid distributor and 90° phase shifter, connected to a reader/writer, generates a circular polarized wave to improve access accuracy and stability

Methodology Applied
Scientific EffectCircular polarized wave generation: Electromagnetic Induction

Implementation Method 2

multi-filler helical antennas with a hybrid distributor and 90° phase shifter

Methodology Applied
Scientific EffectSignal distribution and phase shifting: Electromagnetic Induction

Data Source

PatentEP2913781B1Tag access device
Publication Date: 2022.07.20 FUJITSU FRONTECH LTD
  • EP2913781B1 patent drawingFigure 1
  • EP2913781B1 patent drawingFigure 2
  • EP2913781B1 patent drawingFigure 3

AI summary

To achieve improvement in accuracy in reading and writing of a tag. A tag access apparatus (1) accesses an RFID tag (11) provided with a first antenna having a radio wave directivity along a longitudinal direction of a plurality of test tubes (10) arranged at a predetermined interval. The tag access apparatus (1) has a multi-filler helical antenna (22) which is provided in a direction opposite to the radio wave directivity of the first antenna and which maintains an electric field strength at a central part of the multi-filler helical antenna (22) at a level that allows access to the RFID tag (11), at the time of access to the RFID tag (11).