CNT Antenna Reflector Assembly for Thermal Distortion Control
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Solution Overview
Problem
Gold plated wire mesh antennas used in satellites suffer from high solar absorptivity to hemispherical emissivity ratio and high Coefficient of Thermal Expansion, leading to thermal distortion and degraded performance due to on-orbit temperatures.
Innovation Solution
The use of Carbon Nano-Tube material with a low solar absorptivity to hemispherical emissivity ratio and low Coefficient of Thermal Expansion, formed into wedge-shaped pieces and bonded using a resin film adhesive to create a three-dimensional contoured antenna reflector with a parabolic shape, reducing thermal distortion and enhancing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If gold plated wire mesh material is used for antenna reflector, then the antenna can be manufactured with conventional materials and processes, but the high solar absorptivity to hemispherical emissivity ratio results in high mesh temperatures and thermal distortion
Solution Approach 1:
The patent changes the material parameters by transitioning from gold plated wire to Carbon Nano-Tube material, which fundamentally alters the solar absorptivity to hemispherical emissivity ratio from high (approximately 8) to low (less than 2.0), thereby reducing mesh temperatures and thermal distortion while maintaining manufacturability through the described bonding process
Solution Approach 2:
The patent employs Carbon Nano-Tube material as a composite alternative to conventional gold plated wire mesh, combining the advantages of low solar absorptivity, low hemispherical emissivity, and low Coefficient of Thermal Expansion in a single material system that resolves the thermal performance issues of traditional materials
2Device complexity
If gold plated wire mesh material is used for antenna reflector, then the antenna structure can be simple and conventional, but the high Coefficient of Thermal Expansion results in thermal distortion and degraded antenna performance
Solution Approach 1:
The patent changes the Coefficient of Thermal Expansion parameter by using Carbon Nano-Tube material with CTE of less than 1.0 ppm/C°, compared to the high CTE of gold plated wire (approximately 4.5-5.0 ppm/C°), thereby achieving superior thermal stability and preventing antenna reflector distortion under thermal cycling conditions
Solution Approach 2:
The patent creates a new material model (Carbon Nano-Tube mesh) that copies and improves upon the functional characteristics of conventional wire mesh while eliminating its thermal expansion deficiencies, achieving both structural simplicity and thermal stability
3Stability of the object's composition
If Carbon Nano-Tube material is cut into wedge shaped pieces and bonded together to form three dimensional contoured surface, then thermal distortion is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent divides the Carbon Nano-Tube material into multiple wedge-shaped pieces that can be individually handled, positioned, and bonded to form the three-dimensional contoured antenna reflector surface, making the manufacturing of complex shapes feasible while maintaining the thermal stability benefits of the CNT material
Solution Approach 2:
The patent introduces a resin film adhesive as an intermediary bonding agent that facilitates the assembly of wedge-shaped CNT pieces into a three-dimensional structure, enabling complex shape fabrication while maintaining thermal stability through the use of low-CTE CNT material
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 Carbon Nano-Tube material reduces thermal distortion and maintains antenna performance by minimizing mesh temperatures and thermal expansion, enabling higher operational frequency capabilities and improved antenna gain.
Implementation Method 1
bonding together the wedge shaped pieces using a resin film adhesive (e.g., cyanate ester resin film) to form the antenna reflector
Implementation Method 2
applying heat and pressure to the resin film adhesive and the plurality of wedge shaped pieces of CNT material
Implementation Method 3
applying heat to (i) increase a temperature of the wedge shaped pieces from a first temperature to a second temperature, and (ii) reduce a viscosity of the resin film adhesive
Implementation Method 4
applying pressure to the wedge shaped pieces and the resin film adhesive; The pressure may be applied using at least one of a caul structure and a vacuum bag
Implementation Method 5
allowing the resin film adhesive to flow into the CNT material and cure so as to stiffen the CNT material, whereby the antenna reflector is formed
Implementation Method 6
applying heat to (i) increase the temperature of the wedge shaped pieces from the second temperature to a third temperature, and (ii) initiate a cross-linking chemical reaction to occur within the resin system; waiting a second period of time to allow an acceptable percentage (e.g., >50%) of the resin system to cross-link
Implementation Method 7
The CNT material has a low solar absorptivity to hemispherical emissivity ratio and low Coefficient of Thermal Expansion, formed into wedge-shaped pieces and bonded using a resin film adhesive to create a three-dimensional contoured antenna reflector with a parabolic shape, reducing thermal distortion
Implementation Method 8
The CNT material has a low solar absorptivity to hemispherical emissivity ratio and low Coefficient of Thermal Expansion
Data Source
AI summary
Systems and methods for making an antenna reflector. The methods comprise: obtaining a Carbon Nano-Tube (“CNT”) material; cutting the CNT material into a plurality of wedge shaped pieces; and bonding together the wedge shaped pieces using a resin film adhesive to form the antenna reflector with a three dimensional contoured surface.