Parabolic Reflector Edge Embedded in Absorber

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Solution Overview

Problem

Existing compact range antenna and radar-cross-section measurement facilities face challenges in reducing edge diffractions, which distort measurements, especially at lower frequencies like 100 MHz, requiring large reflector dimensions and additional space for serrations or rolled edges, making them cost-prohibitive.

Innovation Solution

The outer periphery of the parabolic reflector is extended to the interior walls, floor, and ceiling of the anechoic chamber, with the edge fully embedded in absorber material to absorb electromagnetic energy, reducing edge diffractions and allowing for a more compact setup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If serrations or rolled edges are added to reduce edge diffractions, then measurement accuracy is improved, but reflector dimensions and chamber space requirements increase

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidreflector dimensions

Core Design Contradiction:

Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent extracts the edge diffraction problem by removing the traditional serrated or rolled edge structures and instead embedding the reflector edge directly into the absorber material. This eliminates the need for additional space-consuming edge treatments while still addressing the diffraction issue through the absorber interface.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the reflector edge termination with the absorber material by embedding the edge directly into the absorber. This combination eliminates the need for separate edge treatment structures (serrations or rolls) and achieves edge diffraction reduction through the integrated absorber interface.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If large reflector dimensions are used to reduce edge diffractions, then measurement accuracy is improved, but chamber size and cost increase

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidchamber size

Core Design Contradiction:

Measurement precisionVSVolume of stationary object

Solution Approach 1:

The patent converts the harmful edge diffraction effect into a beneficial absorption opportunity by embedding the reflector edge in the absorber material. The edge diffraction that would normally contaminate the test zone is instead directed into the absorber where the electromagnetic energy is absorbed, transforming a measurement error source into an effective solution.

Inventive Principle:

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

3Loss of energy

If absorber material is used to line chamber walls, then electromagnetic energy absorption is improved, but edge diffraction reduction requires additional space

Engineering Contradiction:

Improveelectromagnetic energy absorptionVSAvoidspace for edge treatment

Core Design Contradiction:

Loss of energyVSLength of stationary object

Solution Approach 1:

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

This solution significantly reduces edge diffraction distortions, enabling compact range measurements at lower frequencies without the need for large reflector dimensions, allowing for a smaller anechoic chamber size while maintaining accurate wave-front collimation.

Implementation Method 1

The outer periphery of the reflector is embedded in the absorber so that electromagnetic energy incident upon the interface of the reflector and absorbers, and energy scattered from the edge of the reflector, is absorbed by the absorbers.

Methodology Applied

Scientific EffectElectromagnetic absorption: Absorption (EM radiation)

Implementation Method 2

a parabolic-shaped reflector to transform wave-fronts from a spherical wave-front coming from a feed source to form a substantially planar wave-front

Methodology Applied

Scientific EffectElectromagnetic reflection: Reflection

Data Source

PatentUS8330640B2Termination of edges of a parabolic reflector in a compact range

Publication Date: 2012.12.11 ETS LINDGREN INC

AI summary

Embodiments include an anechoic chamber lined with absorber to absorb electromagnetic energy incident upon the absorber and reflector edge interfaces. The chamber comprises a reflector to reflect waves from a source to form a substantially plane wave field in a test zone within the chamber. In some embodiments, the outer periphery of the reflector extends to the interior walls, floor and ceiling of the chamber. The outer periphery of the reflector is embedded in the absorber in some embodiments.