Passive Sensor Identification via Radar Cross Section Diffuser

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Solution Overview

Problem

Existing wireless sensors for measuring physical quantities like temperature, pressure, and gas concentration face limitations due to energy requirements, which lead to high costs, bulkiness, and reduced lifespan, and current passive sensors suffer from short interrogation distances and calibration difficulties.

Innovation Solution

A wireless measuring device with a passive detector and a multi-band electromagnetic diffuser having a specific radar equivalent surface, allowing for identification and measurement of physical quantities at distances of several tens of meters without energy modulation, using the radar cross section of the diffuser to identify and measure variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If active detectors with power supply are used, then detection capability is improved, but device weight, cost, and lifespan are worsened

Engineering Contradiction:
Improvedetection capabilityVSAvoiddevice weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The invention extracts and removes the power supply, data processing circuit, and battery from the detector, leaving only the essential sensing element. This extracted passive detector is then associated with an electromagnetic diffuser that has a specific radar equivalent surface, enabling identification and measurement without active components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the electrical/active detection system with an electromagnetic passive detection system. Instead of using powered detectors that consume energy, the system uses a passive detector combined with an electromagnetic diffuser that reflects electromagnetic waves, substituting mechanical/electrical power requirements with electromagnetic field interactions.

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

2Ease of operation

If passive SAW sensors are used, then wireless operation is achieved, but interrogation distance is limited to a few tens of centimeters

Engineering Contradiction:
Improvewireless operationVSAvoidinterrogation distance
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The invention changes the electromagnetic characteristics by introducing a diffuser with a specific radar equivalent surface. This modifies how electromagnetic waves interact with the sensor, enhancing the reflection signal strength and enabling detection at distances of several tens of meters rather than just a few tens of centimeters.

Inventive Principle:
Principle #35Parameter changes

3Loss of information

If RFID tags are added for identification, then detector identification is enabled, but reading range is limited to a few meters

Engineering Contradiction:
Improvedetector identificationVSAvoidreading range
Core Design Contradiction:
Loss of informationVSLength of stationary object

Solution Approach 1:

The electromagnetic diffuser with a specific radar equivalent surface serves multiple functions: it enhances the interrogation distance for detection and simultaneously provides a unique identification signature for the detector. This single component replaces the need for separate RFID tags and extends the operational range.

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

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 efficient, cost-effective, and precise wireless measurements of physical quantities over extended distances without energy consumption, improving sensor lifespan and reducing installation complexities.

Implementation Method 1

at least one electromagnetic diffuser (14) having a specific radar equivalent surface, associated to the detector (12) to identify the detector (12) by means of the radar cross section of the electromagnetic diffuser (14)

Methodology Applied
Scientific EffectRadar cross section: Radar

Data Source

PatentEP2435798B1Measuring device with an electromagnetic diffuser
Publication Date: 2013.05.01 CENT NAT DE LA RECH SCI (C N R S)
  • EP2435798B1 patent drawingFigure 1~2(b)
  • EP2435798B1 patent drawingFigure 3~5
  • EP2435798B1 patent drawing

AI summary

Measurement device (10) for measuring at least one physical quantity comprising at least one detector (12) configured so as to detect a variation in said at least one physical quantity, said measurement device furthermore comprising at least one multi-band electromagnetic diffuser (14) having a specific equivalent radar cross section, associated with the detector (12) for identifying the detector (12) by means of the equivalent radar cross section of the electromagnetic diffuser (14).