Tubular LC Resonator Diffraction Grating for Facade Reflection Control

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Solution Overview

Problem

Existing solutions for mitigating parasitic reflections of radioelectric waves from building facades, particularly in airport areas, face challenges due to the size, weight, and fragility of conventional diffraction structures, which complicate installation and affect the structural integrity of the facade.

Innovation Solution

A diffraction grating device comprising tubular structural elements with specific dimensions and geometry, acting as LC resonators, that adjust their spacing based on wavelength and angle of incidence to create a phase shift, allowing for effective diffraction of radioelectric waves in a preferred direction, while being more rigid and easier to install due to smaller dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional diffraction structures with large dimensions are used to prevent parasitic reflections, then the diffraction effectiveness is improved, but the installation complexity and structural load on the facade increase

Engineering Contradiction:
Improveparasitic reflectionsVSAvoidinstallation complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the dimensional parameters of the diffraction structure by using resonant elements with much smaller dimensions than conventional structures. The resonant frequency is tuned to match the problematic radio wave frequency, allowing effective diffraction with compact elements that have dimensions independent of the wavelength, thereby reducing installation complexity while maintaining diffraction effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by designing resonant elements with specific electromagnetic properties tailored to the problematic frequency. Each resonant element is locally optimized with specific dimensions and resonant frequencies to target particular parasitic reflection issues, allowing selective mitigation without requiring large-scale structural modifications.

Inventive Principle:
Principle #3Local quality

2Weight of stationary object

If hollow tubular elements are used to reduce weight, then the structural load on the facade is reduced, but the rigidity and mechanical strength of the elements decrease

Engineering Contradiction:
Improvestructural weightVSAvoidelement rigidity
Core Design Contradiction:
Weight of stationary objectVSStrength

Solution Approach 1:

The patent employs composite construction for the resonant elements, combining conductive materials with dielectric or magnetic materials. This composite approach allows the hollow tubular structure to maintain reduced weight while the internal materials provide the necessary rigidity and electromagnetic resonance properties, resolving the contradiction between weight reduction and structural strength.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If the spacing between structural elements is increased to reduce facade load, then the installation becomes easier, but the diffraction precision and control over reflection direction deteriorate

Engineering Contradiction:
Improveinstallation easeVSAvoiddiffraction precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent changes the spacing parameter from being wavelength-dependent to being determined by the resonant frequency of the elements. This allows for larger spacing between elements compared to conventional structures while maintaining precise diffraction control, as the resonant elements actively control the electromagnetic field rather than relying solely on geometric spacing.

Inventive Principle:
Principle #35Parameter changes

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 effectively reduces parasitic reflections with a more compact and rigid structure, minimizing disruptions to sensitive areas like airport runways, while being less obtrusive and easier to install on building facades, thus enhancing the occupancy rate of airport areas.

Implementation Method 1

A diffraction grating device comprising tubular structural elements with specific dimensions and geometry, acting as LC resonators, that adjust their spacing based on wavelength and angle of incidence to create a phase shift

Methodology Applied
Scientific EffectLC resonance: Resonance

Implementation Method 2

allowing for effective diffraction of radioelectric waves in a preferred direction

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

create a phase shift, allowing for effective diffraction of radioelectric waves in a preferred direction

Methodology Applied
Scientific EffectPhase shift:

Data Source

PatentEP2789051B1Use of a diffracting device
Publication Date: 2020.11.25 AIRBUS (SAS)
  • EP2789051B1 patent drawingFigure 1~2
  • EP2789051B1 patent drawingFigure 3~5
  • EP2789051B1 patent drawingFigure 6

AI summary

A diffractive device for fitting to a façade (11) of a building, or to any other reflective wall, exposed to electromagnetic radiation emitted by a source located at a distance from the building, the device comprising a plurality of tubular resonant elements (12) arranged on the façade of said building, characterised in that said resonant elements are arranged in a substantially parallel manner on the façade (11) of said building in such a way as to form a diffraction grating and are oriented in a substantially perpendicular direction to the plane defined by the propagation vectors of the incident and reflected electromagnetic waves, each resonant element (12) being configured to form an LC resonator capable of re-radiating a wave corresponding to the incident wave affected by a phase shift; the set of resonant elements being arranged in such a way that the incident wave is diffracted in a preferential direction. The diffraction grating formed in this way is advantageously not as thick as the existing devices. The overall structure is both lighter and less susceptible to deformation.