Millimeter-Wave Radar Liquid Detection for Contactless Sensing

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Solution Overview

Problem

Conventional electronic liquid detection sensors rely on direct contact with liquids and changes in conductivity, limiting their ability to detect liquids in applications where contact is not feasible, such as in moving surfaces or unknown environments.

Innovation Solution

A millimeter-wave radar system generates N virtual channels of sensed data, processing them to create a 2D radar image with azimuth and range information. This image is then transformed into a multi-dimensional data structure, compared to a reference structure, and analyzed to determine the presence of liquid in the field of view.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional electronic liquid detection sensors are used, then liquid detection is achieved through direct contact and conductivity change, but the sensor cannot detect liquids in applications where contact is not feasible

Engineering Contradiction:
Improveliquid detection capabilityVSAvoidcontact requirement
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent replaces conventional contact-based electronic sensors with a millimeter-wave radar system that uses electromagnetic waves to detect liquids. The radar sensor transmits millimeter-wave signals that reflect off liquid surfaces, allowing detection without physical contact. This substitution of detection mechanism enables liquid detection in applications where direct contact is not feasible, such as moving surfaces or unknown environments.

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

2Adaptability or versatility

If millimeter-wave radar sensor is used, then contactless liquid detection is achieved, but the device complexity increases due to signal processing requirements

Engineering Contradiction:
Improvecontactless detection capabilityVSAvoidsignal processing system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transforms the one-dimensional radar signal data into a two-dimensional radar image through signal processing. This dimensional transformation allows the system to visualize and analyze liquid detection data in terms of azimuth and range, making the complex signal processing results more interpretable and enabling accurate liquid detection despite the increased device complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If conventional conductivity-based sensors are used, then simple detection is achieved, but the measurement precision is limited to contact points only

Engineering Contradiction:
Improveliquid presence detectionVSAvoiddetection system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the detection field into multiple virtual channels, allowing the radar sensor to analyze different spatial regions independently. This segmentation enables precise localization of liquid presence by comparing signals from multiple virtual channels, thereby improving measurement precision across the entire detection area rather than at a single contact point.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a virtual representation of the physical detection environment by generating a radar image that copies the spatial distribution of liquids. This virtual copy allows for accurate analysis and measurement of liquid presence without requiring physical contact, thereby improving measurement precision while managing device complexity through software-based processing.

Inventive Principle:
Principle #26Copying

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 system effectively detects liquids in applications where direct contact is not possible, including moving surfaces and unknown environments, providing accurate liquid detection capabilities.

Implementation Method 1

a millimeter-wave radar sensor circuit configured to generate N virtual channels of sensed data

Methodology Applied
Scientific EffectRadar: Radar

Data Source

PatentEP3557283B1Liquid detection using millimeter-wave radar sensor
Publication Date: 2025.05.28 INFINEON TECHNOLOGIES AG
  • EP3557283B1 patent drawingFigure 1~2
  • EP3557283B1 patent drawingFigure 3A
  • EP3557283B1 patent drawingFigure 3B

AI summary

A device includes: a millimeter-wave radar sensor circuit configured to generate N virtual channels of sensed data, where N is an integer number greater than one; and a processor configured to: generate a 2D radar image of a surface in a field of view of the millimeter-wave radar sensor circuit based on sensed data from the N virtual channels of sensed data, where the 2D radar image includes azimuth and range information, generate a multi-dimensional data structure based on the 2D radar image using a transform function, compare the multi-dimensional data structure with a reference multi-dimensional data structure, and determine whether liquid is present in the field of view of the millimeter-wave radar sensor circuit based on comparing the multi-dimensional data structure with the reference multi-dimensional data structure.