RCS Reduction Surface Using Destructive Radar Wave Interference

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Solution Overview

Problem

Radar test systems face perturbations due to unwanted reflections at surfaces, which can lead to signal disturbances, despite the use of absorber materials.

Innovation Solution

An RCS reduction surface is created by combining absorber portions and reflecting portions, spaced to achieve destructive interference of radar waves, thereby reducing the overall radar cross section.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If absorber material is used to reduce reflections, then radar cross section is reduced, but leftover perturbations remain due to unwanted reflections

Engineering Contradiction:
Improveradar cross sectionVSAvoidsignal accuracy
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The surface is segmented into multiple types of portions (absorber portions and reflecting portions) rather than using a single uniform material. This segmentation allows different portions to perform different functions - absorbing radar waves in certain directions while reflecting them in others, thereby reducing overall radar cross section while maintaining signal accuracy through controlled interference patterns

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the surface are assigned different local properties - some areas have absorber material while others have reflecting material. This local quality variation enables the surface to manipulate radar wave behavior differently at different locations, creating destructive interference for unwanted reflections while preserving desired signal characteristics

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If absorber material covers all surfaces, then reflections are reduced, but perturbations persist and measurement precision is compromised

Engineering Contradiction:
Improveunwanted reflectionsVSAvoidsignal measurement accuracy
Core Design Contradiction:
Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The invention converts the harmful effect of reflections into a beneficial one by strategically placing reflecting portions alongside absorber portions. The reflected waves from the reflecting portions are designed to interfere destructively with waves from absorber portions, turning what would normally be unwanted reflections into a mechanism for reducing overall radar cross section and improving measurement precision

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 solution effectively minimizes perturbations caused by reflections, improving the accuracy of radar test systems and reducing the radar cross section of objects.

Implementation Method 1

The at least one absorber portion and the at least one reflecting portion are spaced from each other such that radar waves, which are reflected at the at least one absorber portion and at the at least one reflecting portion, have a path difference of half of the wavelength or a path difference of odd integer multiples of half of the wavelength of the radar waves

Methodology Applied
Scientific EffectDestructive interference: Interference

Implementation Method 2

The at least one absorber portion is configured to absorb radar waves

Methodology Applied
Scientific EffectElectromagnetic absorption: Absorption (EM radiation)

Implementation Method 3

The at least one reflecting portion is configured to reflect radar waves

Methodology Applied
Scientific EffectElectromagnetic reflection: Reflection

Data Source

PatentEP3945337B1RCS reduction surface, RCS reduction member, and radar test system
Publication Date: 2025.02.12 ROHDE & SCHWARZ GMBH & CO KG
  • EP3945337B1 patent drawingFigure 1~2
  • EP3945337B1 patent drawingFigure 3a~3c
  • EP3945337B1 patent drawingFigure 4

AI summary

An RCS reduction surface (25) for reducing a radar cross section of an object is described. The RCS reduction surface (25) comprises at least one absorber portion (26, 28), wherein the absorber portion (26,28) is configured to absorb radar waves. The RCS reduction surface (25) further comprises at least one reflecting portion (30), wherein the reflecting portion (30) is configured to reflect radar waves. A first plane (E 1) being associated with a top surface of the absorber portion (26, 28) and a second plane (E 2) being associated with a top surface of the reflecting portion (30) are spaced from each other by a predefined distance (Δd). The predefined distance (Δd) is configured such that radar waves with a predefined wavelength range that are reflected at the absorber portion (26, 28) and at the surface of the reflecting portion (30) interfere destructively with each other. Further, an RCS reduction member (24) and a radar test system (10) are described.