Dual-Frequency Microwave Detection for Obstruction Penetration

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Solution Overview

Problem

Existing technologies face challenges in distinguishing between objects located behind and in front of an obstruction using microwave detection, as both types of objects are often indistinguishable due to similar travel times and phase differences, leading to inaccurate ranging and identification.

Innovation Solution

A device utilizing at least two distinct microwave frequencies, where one frequency penetrates the obstruction and the other does not, allowing for clear differentiation between objects in front of and behind the obstruction by exploiting frequency-dependent attenuation, with the first frequency experiencing low attenuation and the second experiencing high attenuation, enabling distinct detection signals for each scenario.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single microwave frequency is used for detection, then the device complexity is reduced, but the ability to distinguish between objects in front of and behind the obstruction is lost

Engineering Contradiction:
Improvedetection system complexityVSAvoidobject location discrimination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by using multiple microwave frequencies with different penetration characteristics. The first frequency (lower frequency) penetrates the obstruction to detect objects behind it, while the second frequency (higher frequency) does not penetrate the obstruction and only detects objects in front of it. By comparing detection results across these frequency parameters, the system achieves accurate object location discrimination without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple frequencies are used to improve ranging accuracy, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improveranging accuracyVSAvoidmulti-frequency system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by assigning different frequencies to different detection purposes: the lower frequency is specifically used for detecting objects behind the obstruction (where penetration is needed), while the higher frequency is specifically used for detecting objects in front of the obstruction (where no penetration occurs). This localized frequency assignment improves ranging accuracy for each specific detection scenario while managing overall system complexity.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If phase difference measurement is used for ranging, then the measurement precision is improved, but the reliability decreases due to phase distortion by the obstruction

Engineering Contradiction:
Improveranging precisionVSAvoidrange information accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent converts the harmful effect of phase distortion by the obstruction into a beneficial detection mechanism. Instead of trying to measure phase differences (which are distorted by the obstruction), the system uses the fact that the obstruction blocks the higher frequency while allowing the lower frequency to pass. This transforms the phase distortion problem into a useful frequency-dependent attenuation effect that enables reliable object location identification.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 allows for accurate identification and imaging of objects behind obstructions by using frequency differences to distinguish between objects in front of and behind the obstruction, providing clear and reliable detection results.

Implementation Method 1

a first detection unit arranged for operating at a first frequency and producing first detection signals, the first frequency being substantially capable of penetrating the obstruction and reaching an object located behind it

Methodology Applied
Scientific EffectElectromagnetic wave penetration: Absorption (EM radiation)

Implementation Method 2

a second detection unit arranged for operating at a second frequency and producing second detection signals, the second frequency being substantially incapable of penetrating the obstruction and reaching an object located behind it

Methodology Applied
Scientific EffectElectromagnetic wave attenuation: Absorption (EM radiation)

Implementation Method 3

By using at least two distinct frequencies, of which the first one is substantially capable and the second one is substantially incapable of penetrating the obstruction and reaching an object located behind it, a clearly detectable distinction can be made between objects behind and objects in front of the obstruction

Methodology Applied
Scientific EffectFrequency-dependent attenuation:

Data Source

PatentEP2235560B1Detecting concealed objects using electromagnetic waves
Publication Date: 2012.11.21 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP2235560B1 patent drawingFigure 1a~1b
  • EP2235560B1 patent drawingFigure 2~3c
  • EP2235560B1 patent drawingFigure 4~5

AI summary

A device (1) for detecting objects (2) located behind an obstruction (5), the device comprising: a first detection unit arranged for operating at a first microwave frequency and producing first detection signals, a second detection unit arranged for operating at a second microwave frequency and producing second detection signals, and a processing unit for processing the first detection signals and the second detection signals so as to detect objects (2, 3). The first microwave frequency is chosen so as to penetrate the obstruction (5) while the second microwave frequency is chosen so as not to penetrate the obstruction. The processing unit is arranged for establishing which objects are not shared by the first detection signals and the second detection signals and are therefore located behind the obstruction, in contrast to objects (3) located in front of the obstruction. The detection units are preferably frequency-modulated continuous wave radar units.