Carbon Nanotube Yarn Mesh Antenna for Thermal Distortion
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Solution Overview
Problem
Gold plated wire mesh antennas 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
A mesh antenna reflector formed from Carbon Nano-Tube yarn with a low solar absorptivity to hemispherical emissivity ratio and low Coefficient of Thermal Expansion, offering reduced thermal distortion and enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If gold plated wire mesh material is used for antenna reflector, then the antenna can provide high gain, but the high solar absorptivity to hemispherical emissivity ratio results in high mesh temperatures
Solution Approach 1:
The patent changes the material parameter from gold plated wire to carbon nanotube yarn, which fundamentally alters the solar absorptivity to hemispherical emissivity ratio from approximately 8 to a much lower value. This parameter change maintains the antenna's RF reflective properties while dramatically reducing solar heating, thus resolving the contradiction between maintaining antenna gain and reducing mesh temperature.
Solution Approach 2:
The patent employs carbon nanotube yarn as a composite material that combines the necessary electrical conductivity for RF reflection with superior thermal radiation properties. The carbon nanotube structure provides both the functional requirements for antenna operation and the thermal management capabilities needed to operate at lower temperatures in the space environment.
2Shape
If gold plated wire mesh material is used for antenna reflector, then the antenna structure can be formed, but the high Coefficient of Thermal Expansion results in thermal distortion of the antenna reflector
Solution Approach 1:
The patent changes the material from gold plated tungsten or molybdenum wire to carbon nanotube yarn, which has a Coefficient of Thermal Expansion more than an order of magnitude lower (approximately -0.3 ppm/C° compared to 4.5-5.0 ppm/C°). This parameter change ensures that the antenna reflector maintains its precise parabolic shape and dimensional stability across the wide temperature ranges experienced in orbit, eliminating thermal distortion while preserving the required geometric form.
3Weight of stationary object
If carbon nanotube yarn is used to form mesh material, then the areal density is reduced to less than ten percent of gold plated wire mesh, but the manufacturing complexity increases
Solution Approach 1:
The patent utilizes the flexible, yarn-based nature of carbon nanotube materials to create lightweight mesh structures through knitting techniques. The carbon nanotube yarn can be directly knitted into mesh configurations, eliminating the need for heavy structural support that would be required with traditional rigid wire materials. This approach achieves extreme weight reduction while maintaining manufacturability through established textile processing methods.
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 yarn mesh antennas exhibit lower thermal distortion and improved operational frequency capabilities with reduced areal density, addressing the thermal issues of gold plated wire mesh antennas.
Implementation Method 1
a mesh material formed of a Carbon Nano-Tube ("CNT") yarn that is reflective of radio waves
Implementation Method 2
low solar absorptivity to hemispherical emissivity ratio
Implementation Method 3
low Coefficient of Thermal Expansion (CTE
Data Source
AI summary
An antenna reflector comprising a mesh material formed of a Carbon Nano-Tube (“CNT”) yarn that is reflective of radio waves and has a low solar absorptivity to hemispherical emissivity ratio (αsolar/εH ratio) and a low Coefficient of Thermal Expansion (“CTE”).