Microwave Sensor Tags for Compact Gas Detection

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Solution Overview

Problem

Existing gas detection technologies are either large, costly, and unreliable, or they lack sensitivity and are not suitable for low-cost implementation on unmanned vehicles.

Innovation Solution

A novel planar sensing apparatus using microwave signals and circuits with active layers of palladium, graphene, or metal oxides, which are embedded in classical microwave circuits to form sensors, allowing for high sensitivity gas detection in a compact, low-cost format.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional infrared laser implementations are used for gas detection, then detection capability is achieved, but the device becomes large, heavy, and costly

Engineering Contradiction:
Improvedetection capabilityVSAvoiddevice size and weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent replaces traditional mechanical/optical gas detection systems (infrared lasers, Raman spectroscopy equipment) with a microwave-based sensor system. This substitution uses microwave signals interacting with gas molecules to induce rotational transitions, enabling detection without bulky optical components. The microwave sensor achieves gas detection capability while dramatically reducing device size and weight compared to conventional infrared laser implementations.

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

Solution Approach 2:

The patent changes the operational parameter from optical frequency (infrared) to microwave frequency for gas detection. By operating in the microwave regime, the sensor can detect gas molecules through rotational spectroscopy principles using electromagnetic waves at lower frequencies, which allows for compact antenna designs and smaller overall device dimensions while maintaining detection sensitivity.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If ion mobility spectrometers with radioactive materials are used, then detection sensitivity is improved, but cost and operational complexity increase

Engineering Contradiction:
Improvedetection sensitivityVSAvoidoperational complexity and cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs disposable or replaceable microwave sensor tags that can be easily deployed and discarded after use. These sensor tags are inexpensive to manufacture compared to ion mobility spectrometers, eliminating the need for expensive radioactive materials and complex calibration procedures. The simple microwave-based design allows for mass production at low cost while maintaining adequate detection sensitivity for the intended applications.

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

Solution Approach 2:

The patent extracts and removes the radioactive material component from the detection system entirely. By using microwave electromagnetic fields instead of radioactive ionization sources, the system achieves gas detection without the safety hazards, regulatory burdens, and high costs associated with radioactive materials. The microwave sensor tag uses non-ionizing radiation to interact with gas molecules, simplifying operational requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If colorimetric sensors are used for gas detection, then portability is improved, but false alarms increase and liquid detection is limited

Engineering Contradiction:
ImproveportabilityVSAvoidfalse alarm rate
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses microwave electromagnetic oscillation instead of chemical color change mechanisms. The microwave sensor tag transmits electromagnetic waves that interact with gas molecules, causing rotational transitions that are detected as changes in microwave signal characteristics. This physical measurement approach is specific to gas-phase molecules and does not produce false alarms from liquid contaminants or environmental factors that commonly affect colorimetric sensors.

Inventive Principle:
Principle #18Mechanical vibration

4Volume of moving object

If micro-resistor arrays with metal oxide semiconductor are used, then size is reduced and response speed is improved, but sensitivity is lost

Engineering Contradiction:
Improvesensor sizeVSAvoiddetection sensitivity
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent employs composite sensor tag structures that integrate microwave circuitry, antenna elements, and sensing materials in a multi-layer configuration. The sensor tag combines conductive materials for microwave transmission with gas-sensitive materials that modulate the microwave signal when exposed to target gases. This composite approach maintains compact size while enhancing detection sensitivity through the synergistic interaction of different materials and the microwave field.

Inventive Principle:
Principle #40Composite materials

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 enables highly sensitive detection of gases, including nerve agents, at low concentrations, with a compact, low-cost sensor that can be easily integrated into unmanned vehicles or used as wearable tags.

Implementation Method 1

Gas molecules are detected by inducing rotational transitions and measuring the resulting change in electrical properties of an active layer

Methodology Applied
Scientific EffectRotational transitions: Microwave Radiation

Data Source

PatentEP4455647B1Sensor and sensor system for gas detection
Publication Date: 2025.04.02 CENT TECNOLOGIC DE TELECOMUNICACIONS DE CATALUNYA - CTTC
  • EP4455647B1 patent drawingFigure 1
  • EP4455647B1 patent drawingFigure 2
  • EP4455647B1 patent drawingFigure 3

AI summary

Different aspects of the invention comprise a different way of detecting nerve agents using low-cost wireless sensor tags that can conform to different surfaces and can be easily integrated on unmanned vehicles or used as wearable sensor tags. The proposed low-cost wireless sensor tags can conform easily to different surfaces and sensor data can be displayed on a handheld receiver for stand-off detection.