Chipless RFID Tag Multimode Resonator Design

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Solution Overview

Problem

Conventional chipless RFID tags require precise manufacturing processes, result in larger tags, and higher costs due to the need for accurate fine working processes and limited information capacity, while also being sensitive to environmental factors like temperature and radiation.

Innovation Solution

The use of a transmission line type multimode resonator with a Stepped Impedance Resonator (SIR) structure that allows control over higher-order mode resonance frequencies by varying the resonator structure, enabling the assignment of code information to specific resonance frequencies and allowing for smaller, cost-effective tag implementation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional chipless RFID tags use traditional resonator structures, then manufacturing precision requirements increase and tag size increases, but information capacity remains limited and costs increase

Engineering Contradiction:
Improvemanufacturing precisionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The resonator is divided into multiple sections with different impedance levels (stepped impedance structure). Each section contributes to generating specific resonance frequencies, allowing complex information encoding through simple structural variations that are easy to manufacture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent varies impedance parameters along the transmission line to create multiple resonance modes. By changing the impedance levels in different sections, the resonator generates distinct higher-order mode frequencies that encode information without requiring precise manufacturing tolerances.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional RFID tags use semiconductor chips, then read/write functionality is achieved, but cost increases and environmental resistance decreases

Engineering Contradiction:
Improveenvironmental resistanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a simple passive resonator structure without expensive semiconductor chips. The resonator is designed as a disposable, low-cost component that can be manufactured using standard PCB techniques, eliminating the need for complex electronic circuits while maintaining functionality.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the electronic semiconductor chip system with a passive electromagnetic resonator structure. Information is stored and retrieved through resonance frequency characteristics rather than active electronic components, improving environmental resistance to temperature and radiation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If bar codes are used for identification, then cost is low and simplicity is maintained, but confidentiality is poor and reliability is low

Engineering Contradiction:
Improvetag reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The resonator uses multiple resonance frequencies (fundamental and higher-order modes) to encode information. By varying the impedance parameters in different sections, unique frequency combinations are generated that provide reliable, confidential identification beyond simple bar codes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The single resonator structure performs multiple functions: it generates multiple resonance frequencies for information encoding, provides confidential storage without exposed circuits, and maintains reliability through passive construction. The structure replaces both bar codes and semiconductor RFID chips.

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

4Adaptability or versatility

If conventional RFID tags are miniaturized for embedding, then application versatility increases, but operating frequency range becomes limited

Engineering Contradiction:
Improveapplication versatilityVSAvoidoperating frequency range
Core Design Contradiction:
Adaptability or versatilityVSTemperature

Solution Approach 1:

The stepped impedance resonator generates multiple resonance frequencies by varying impedance parameters in different sections. This allows the miniaturized structure to operate across a wide frequency range, supporting millimeter wave bands and various application frequencies without compromising versatility.

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 enables the creation of smaller, cost-effective RFID tags that can operate across multiple frequency bands, withstand environmental obstacles and temperature variations, and maintain confidentiality, while allowing for increased information capacity and robustness against alteration.

Implementation Method 1

the resonance characteristics of the transmission line resonator. This allows the internal circuit not to be exposed to the outside

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2937712B1RFID tag comprising a multimode resonator
Publication Date: 2021.01.27 SAKURA TECH CORP
  • EP2937712B1 patent drawingFigure 1~3
  • EP2937712B1 patent drawingFigure 4~5
  • EP2937712B1 patent drawingFigure 6~7

AI summary

A multimode resonator (1102 ; 1302) and RFID tags (1301) using such multimode resonator (1102 ; 1302) are disclosed, wherein the multimode resonator (1102 ; 1302) has a simple construction that allows it to be manufactured with a sufficiently fine working precision and at the reduced manufacturing costs so that it can process a large amount of information and it can be extended in the future. In accordance with the present invention, chipless RFID tags (1301) and a tag system are provided, wherein the stepped impedance higher-order mode resonator comprises two sets of composite transmission lines (101 ; 102 ; 103 ; 104 ; 201 ; 202 ; 203 ; 204 ; 205) each set having an equal line length and including a plurality of transmission lines (101 ; 102 ; 103 ; 104 ; 201 ; 202 ; 203 ; 204 ; 205) each having a plurality of specific levels to which the transmission line characteristic impedance is assigned, the two sets of composite transmission lines (101 ; 102 ; 103 ; 104 ; 201 ; 202 ; 203 ; 204 ; 205) each connected in series, the two sets being so connected at the center as to form an electrically symmetrical configuration and wherein the chipless RFID tags (1301) and the tag system allow each of the codes to be assigned to each of the structures of the stepped impedance higher-order mode resonator, and allow each of those codes to be identified by detecting each of the combinations of the higher-order mode resonance frequencies that may be produced from each the structures of the resonator (501 ; 604) that corresponds to each of the codes that have been assigned.