Elastic Tensioners for Thermal Protection Membrane Stability

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Solution Overview

Problem

Existing telecommunications antennas face challenges with thermo-elastic deformations and phase shifts due to temperature variations and material differences between thermal protection membranes and reflectors or radiating panels, leading to instability and radiation interference, particularly at high frequencies.

Innovation Solution

The use of elastic tensioners, such as flexible blades made of poly-para-phenylene terephthalamide or polyimide, integrated with the thermal protection membrane to maintain permanent tension between the active face of the transmitter equipment and space, independently of thermal expansions, ensuring consistent phase shifts and stability across a wide temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a thermal protection membrane is placed between the transmitter equipment and space to thermally insulate the equipment, then thermo-elastic deformations are limited, but the membrane induces phase shifts in the radiofrequency waves at high frequencies

Engineering Contradiction:
Improvethermo-elastic deformation stabilityVSAvoidphase shift consistency
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent employs elastic tensioners that can dynamically adjust their tension based on temperature variations. These tensioners are designed to automatically compensate for thermal expansions and contractions of both the membrane and the transmitter equipment, maintaining constant membrane tension and consistent phase shifts across the operating temperature range from -250°C to +400°C

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the physical state and properties of the tensioning system by using elastic materials with specific thermal expansion characteristics. The elastic tensioners are designed with stiffness between 5 N/m and 500 N/m and thickness between 0.1 mm and 2 mm, allowing them to adapt their tensioning force according to temperature changes while maintaining membrane stability

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If turnbuckles are used to guarantee permanent tension of the membrane, then the membrane remains stretched like a drum skin, but the reflector must be immobilized for prolonged periods during installation

Engineering Contradiction:
Improvemembrane tension stabilityVSAvoidreflector immobilization time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-attaching the elastic tensioners to the membrane before mounting the entire assembly on the reflector. This allows the membrane with its tensioning system to be installed as a complete unit, eliminating the need for prolonged reflector immobilization and complex on-site tensioning adjustments

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The elastic tensioners are designed to automatically self-adjust their tensioning force in response to temperature variations without requiring external intervention. The system serves itself by using the thermal expansions and contractions of the membrane and equipment to automatically maintain optimal tension, eliminating the need for manual turnbuckle adjustments

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If U-folded tensioners are used to stretch the membrane, then the membrane is permanently stretched, but the solution becomes bulky and fragile

Engineering Contradiction:
Improvemembrane tension permanenceVSAvoidtensioner structure simplicity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent replaces the bulky U-folded tensioner structure with thin, flexible blade-like tensioners made of elastic material. These flexible strips have a thickness between 0.1 mm and 2 mm and can be directly attached to the membrane perimeter, providing the necessary tensioning force while occupying minimal space and eliminating the complexity of folding mechanisms

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent extracts the essential function of the tensioners (providing outward force on the membrane) from their complex U-folded structural form. By separating the tensioning function from the structural support function, the design uses simple elastic strips that can be directly bonded to the membrane, eliminating unnecessary bulk and fragility while maintaining the tensioning effect

Inventive Principle:
Principle #2Taking out (Extraction)

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 provides a compact, reliable, and reproducible method to maintain membrane tension, reducing immobilization time, ensuring consistent radiation performance and avoiding solar focusing issues, while being applicable to various reflector types and temperature conditions.

Implementation Method 1

a plurality of elastic tensioners designed to keep the thermal protection membrane stretched between a first active face of the transmitter equipment and the space, independently of the thermal expansions of the membrane and of the equipment emitter occurring in a predetermined temperature range

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

independently of the thermal expansions of the membrane and of the equipment emitter occurring in a predetermined temperature range

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

flexible blades having a stiffness greater than the stiffness of the membrane... made of poly-para-phenylene terephthalamide PPD-T or of polyimide

Methodology Applied
Scientific EffectThermal resistance: Thermal Insulation

Data Source

PatentEP2451007B1Device for emitting radio waves, antenna and spacecraft
Publication Date: 2014.11.26 THALES SA
  • EP2451007B1 patent drawingFigure 1a~1b
  • EP2451007B1 patent drawingFigure 2a~2b
  • EP2451007B1 patent drawingFigure 3

AI summary

Device for emitting radio waves comprising a transmitting equipment (13) for a telecommunications antenna (10), a thermal protection membrane (18) for the reflector and means for attaching the thermal protection membrane (18) to the equipment (13), said thermal protection membrane (18) being provided with a plurality of elastic tensioners intended to keep the thermal protection membrane (18) taut between a first active face of the transmitting equipment (13) and space, independently of thermal expansions of the membrane (18) and the transmitting equipment (13) occurring within a predetermined temperature range, when the attachment means ensure the attachment of the membrane (18) to said transmitting equipment (13).