Vehicle Radar Surface Structure Using Out-of-Phase Reflection Cancellation

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Solution Overview

Problem

Radar systems used in Advanced Driver Assistance Systems (ADAS) and Automated Driving Systems (ADS) face challenges with increased Radar Cross Section (RCS) due to reflections from nearby vehicle parts, leading to noise interference and reduced accuracy, which existing solutions like Meta surfaces and Perfect Absorber Materials fail to adequately address due to frequency sensitivity and manufacturing tolerance issues.

Innovation Solution

A radar system incorporating a spatially modulated surface structure that generates out-of-phase reflected waves, reducing reflections and noise by destructive superposition, thereby lowering the Radar Cross Section (RCS) and improving accuracy with reduced sensitivity to manufacturing tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of antennas is increased to achieve special radar radiation patterns, then the radar scan width, depth or resolution is improved, but the Radar Cross Section (RCS) increases leading to more reflections and noise

Engineering Contradiction:
Improveradar scan resolutionVSAvoidRCS and reflections
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies meta-surface structures that convert harmful reflections into beneficial effects by creating destructive interference patterns. The meta-surface modifies the phase and amplitude of reflected waves to cancel out unwanted reflections, thereby reducing RCS while maintaining the radar radiation patterns needed for high-resolution scanning.

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

Solution Approach 2:

The patent changes the electromagnetic parameters of the radar system by introducing meta-surface structures with specific phase shift properties. These structures alter the phase distribution of reflected waves across different frequencies and angles, enabling RCS reduction while preserving the necessary radiation patterns for accurate object detection.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If Meta surfaces or Perfect Absorber Materials are used to reduce reflections, then the RCS is reduced, but the solution becomes highly sensitive to manufacturing tolerances and frequency shifts

Engineering Contradiction:
ImprovereflectionsVSAvoidsensitivity to manufacturing tolerances
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent employs composite meta-surface structures that combine multiple material layers with different electromagnetic properties. This composite approach creates a more robust system that maintains its RCS reduction performance across a broader frequency range and is less sensitive to manufacturing variations compared to single-material Perfect Absorber Materials.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The meta-surface is designed with spatially varying properties where different regions have optimized characteristics for their specific function. This local optimization allows the system to maintain effective RCS reduction performance even when local manufacturing tolerances vary, as each region is designed to be relatively insensitive to its specific variations.

Inventive Principle:
Principle #3Local quality

3Reliability

If the radar is mounted behind the facia, bumper or chassis, then the radar is protected and integrated into the vehicle, but reflections from these nearby parts cause noise interference

Engineering Contradiction:
Improveradar integrationVSAvoidnoise from reflections
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces meta-surface structures as intermediary elements between the radar antenna and the vehicle body parts (facia, bumper, chassis). These meta-surfaces act as mediators that control and manipulate the electromagnetic waves, creating destructive interference patterns that cancel out reflections from the vehicle body, thereby reducing noise while maintaining the radar's integrated mounting position.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 spatially modulated surface structure effectively reduces monostatic and bistatic reflections, resulting in a lower Radar Cross Section (RCS) and enhanced accuracy for radar systems, while being less sensitive to manufacturing tolerances compared to traditional solutions.

Implementation Method 1

the spatially modulated surface structure is configured to generate, from incident radar waves, a first portion of reflected waves and a second portion of reflected waves, wherein the first portion of reflected waves is out of phase in relation to the second portion of reflected waves

Methodology Applied
Scientific EffectDestructive superposition: Interference

Data Source

PatentEP4283326A1Radar system for a vehicle
Publication Date: 2023.11.29 APTIV TECHNOLOGIES AG
  • EP4283326A1 patent drawingFigure 1~2D
  • EP4283326A1 patent drawingFigure 3A~3B
  • EP4283326A1 patent drawingFigure 4A~4B

AI summary

The present disclosure relates to a radar system featuring a reduced radio cross-section (RCS). This is achieved by providing a radar system comprising one or more antenna structures 11 and a spatially modulated surface structure 12, wherein the spatially modulated surface structure 12 is configured to generate, from incident radar waves 2a, a first portion of reflected waves 2b1, 2c1, 2d1 and a second portion of reflected waves 2b2, 2c2, 2d2, wherein the first portion of reflected waves 2b1, 2c1, 2d1 is out of phase in relation to the second portion of reflected waves 2b2, 2c2, 2d2.