Chipless RFID Sensor Tag for Environmental Monitoring

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Solution Overview

Problem

Conventional chemical sensors for environmental conditions are costly due to the need for numerous electronic components, making them unsuitable for widespread, cost-effective use, especially in remote or hard-to-inspect environments.

Innovation Solution

A chipless RFID tag system incorporating a multiresonator with a sensor material of variable electrical conductivity, positioned in interstitial spaces between resonator arms, which attenuates resonation amplitude based on environmental conditions, allowing for cost-effective detection of conditions like humidity and chemical presence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional chemical sensors are used to detect environmental conditions, then measurement precision is improved, but device complexity and cost increase due to numerous electronic components

Engineering Contradiction:
Improveenvironmental condition detectionVSAvoidelectronic components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the sensing function from complex electronic sensors and implements it through a simplified chipless RFID system. The sensor material is integrated directly into the RFID tag structure, eliminating the need for separate electronic sensing components while maintaining environmental condition detection capability through changes in resonation characteristics

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces electronic sensing mechanisms with electromagnetic resonance-based detection. Instead of using electronic components to sense environmental conditions, the system uses changes in the resonation amplitude of RFID tags caused by sensor material properties (electrical conductivity changes) in response to environmental conditions

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

2Ease of manufacture

If chipless RFID tags are used instead of chipped RFID tags, then manufacturing cost is reduced, but data storage and processing capability are limited

Engineering Contradiction:
Improvemanufacturing costVSAvoiddata storage capacity
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent employs chipless RFID tags that are inexpensive to manufacture using printing techniques. These tags are designed for single-use or limited-use applications where complex data storage is not required, but cost-effective deployment is critical, such as in widespread environmental monitoring scenarios

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

3Device complexity

If sensor material is integrated into RFID tag structure, then device complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecomponent assemblyVSAvoidsensor material positioning
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent merges the sensor material integration with the RFID tag manufacturing process itself. The sensor material is incorporated during the printing or fabrication of the tag structure, eliminating separate assembly steps and reducing the need for precise post-manufacturing positioning while maintaining functional performance

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

Enables low-cost, automated monitoring of environmental conditions by correlating resonation amplitude with sensor material conductivity, facilitating remote sensing without the need for complex electronic components.

Implementation Method 1

a sensor material bridging two or more electrically conductive structures of the RFID device, wherein the sensor material has a variable electrical conductivity that is configured to change depending on an environmental condition

Methodology Applied
Scientific EffectVariable electrical conductivity: Conduction (electrical)

Implementation Method 2

one or more of the radio frequencies may include a frequency-dependent antenna load that is intercepted by the receive antenna and causes the multiresonator to resonate

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

a transmit antenna that broadcasts data that is received by the interrogator

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP3244350B1Chemical sensors based on chipless radio frequency identification (RFID) architectures
Publication Date: 2019.07.10 XEROX CORP
  • EP3244350B1 patent drawingFigure 1
  • EP3244350B1 patent drawingFigure 2~4
  • EP3244350B1 patent drawingFigure 5~6

AI summary

A method and structure for a radio frequency identification (RFID) sensor that may be used to monitor various environmental conditions. The environmental condition measured depends on a sensor material used in the RFID sensor. The sensor material is selected based on a flux in electrical conductivity relative to its saturation of the environmental condition being monitored. The sensor material is placed between adjacent electrically conductive structures of the RFID sensor. Upon a change in the environmental condition being measure, the electrical conductivity of the sensor material changes, thereby increasing or decreasing an amplitude of a response by the RFID sensor to an interrogation by an RFID reader.