Dielectric Retroreflector Lens for Reliable Small-Object Radar Detection

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Solution Overview

Problem

Radar-based systems in vehicles face challenges in reliably detecting and identifying small objects such as pedestrians and bicycles due to their weak radar cross-section, and there is a lack of standardization in radar systems across different manufacturers, leading to difficulties in vehicle positioning and autonomous driving.

Innovation Solution

A cylindrical dielectric lens with a retrodirective antenna array that focuses electromagnetic waves onto a focal region, capable of handling multiple polarization schemes and providing a strong, uniform reflection, enhancing the detection of objects and serving as a common denominator for various radar systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If radar-based systems are used to detect small objects such as pedestrians and bicycles, then the systems can provide detection capability, but the detection reliability is poor due to weak radar cross-section

Engineering Contradiction:
Improvedetection reliabilityVSAvoiddifficulty of detecting small objects
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies parameter changes by modifying the electromagnetic wave properties through a dielectric lens with specific refractive index gradient. The lens focuses radar waves onto a retrodirective antenna array, changing the wave concentration parameter to enhance the reflected signal strength from small objects, thereby improving detection reliability without requiring more powerful transmitters.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a dielectric lens as an intermediary component between the radar transmitter and the target objects. This lens mediates the radar wave propagation by focusing the waves and enhancing the interaction with small objects, which have weak radar cross-sections, thereby improving their detectability without directly modifying the objects or the radar system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If different radar polarization schemes are used by various manufacturers, then each manufacturer can optimize their system, but standardization and interoperability are compromised

Engineering Contradiction:
Improveadaptability to different polarization schemesVSAvoidcomplexity of radar system variations
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent achieves universality by designing a dielectric lens with specific symmetry properties that can handle multiple polarization schemes (vertical, horizontal, and circular polarization) equally well. The lens structure is polarization-agnostic, meaning it functions effectively regardless of the incident wave's polarization state, thereby enabling a single apparatus design to work with radar systems from different manufacturers using various polarization standards.

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

3Measurement precision

If GPS-based navigation systems are used for vehicle positioning, then positioning capability is provided, but precision is insufficient for autonomous driving requirements

Engineering Contradiction:
Improvepositioning precisionVSAvoidreliability of position determination
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the GPS satellite-based positioning mechanism with a ground-based radar reflection system. Instead of relying on satellite signals and map data matching, the system uses localized radar waves reflected from known roadside apparatus to determine vehicle position. This substitution provides centimeter-level precision compared to GPS meter-level accuracy, enabling reliable autonomous driving positioning.

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

4Reliability

If sensor fusion combining camera, LIDAR, ultrasound and radar is implemented, then detection capability is enhanced, but system complexity increases

Engineering Contradiction:
Improvedetection reliabilityVSAvoidcomplexity of sensor fusion system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple sensor types into a single radar-based system. By using a dielectric lens to enhance radar wave focusing and a retrodirective antenna array to improve signal reflection, the system achieves detection capabilities previously requiring multiple sensor types. This consolidation maintains high detection reliability while reducing system complexity by eliminating the need for separate camera, LIDAR, and ultrasound systems.

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

The solution improves the reliability and robustness of vehicle-based radar systems by enhancing object detection and positioning, regardless of object size or radar polarization, and facilitates standardization across different radar systems.

Implementation Method 1

a cylindrical element, designed as dielectric lens, having an inner longitudinal axis and comprising a dielectric material with an effective dielectric constant so as to provide for a focusing of an incident electromagnetic wave onto a focus region

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

a retrodirective antenna array comprising at least two antenna elements, said antenna array being positioned with an orientation parallel to said axis at or close to said focal region

Methodology Applied
Scientific EffectRetroreflection: Retroreflector

Data Source

PatentEP3776732B1Apparatus serving as retro-reflective element for electromagnetic waves, and radar system comprising such an apparatus
Publication Date: 2023.12.13 DAMASIA HLDG GMBH
  • EP3776732B1 patent drawingFigure 1A~2I
  • EP3776732B1 patent drawingFigure 2J~2U
  • EP3776732B1 patent drawingFigure 3A~4B

AI summary

Apparatus (100) comprising - a cylindrical element (10) having an inner longitudinal axis (A1) and comprising a dielectric material with an effective dielectric constant so as to provide for a focusing of an incident electromagnetic wave onto a focus region (11), - a retrodirective antenna array (20) comprising at least two antenna elements (30), said antenna array (20) being positioned with an orientation parallel to said axis (A1) at said focus region (11).