Deployable Satellite Reflector Reducing Passive Intermodulation
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Solution Overview
Problem
Deployable satellite reflectors face challenges in minimizing passive intermodulation (PIM) due to the use of woven wire mesh, which requires tight tension maintenance over a wide temperature range and involves complex fabrication and assembly processes.
Innovation Solution
A flexible reflector system comprising a plurality of gores with a thin conductive metal layer sandwiched between dielectric layers, using capacitive coupling between adjacent gores to form a continuous reflective surface, minimizing metal-to-metal interfaces and employing non-metallic fasteners and coatings to reduce PIM.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If woven wire mesh is used for the reflector surface, then the reflector can be deployed, but passive intermodulation increases and tension maintenance becomes difficult
Solution Approach 1:
The patent removes the woven wire mesh structure entirely and replaces it with a dielectric membrane having a continuous conductive coating. This extraction eliminates the metal-to-metal interfaces that generate passive intermodulation while maintaining the deployable reflector functionality through the flexible membrane structure.
Solution Approach 2:
The patent employs a composite structure consisting of a dielectric membrane material (such as polyimide or polyester) coated with a continuous conductive layer (such as aluminum or copper). This composite material provides both the mechanical flexibility needed for deployment and the electromagnetic reflective properties, while avoiding the PIM issues of woven mesh.
2Ease of manufacture
If woven wire mesh is used for the reflector surface, then the reflector can be deployed, but fabrication and assembly become complex
Solution Approach 1:
By removing the woven wire mesh and its associated tensioning mechanisms, the patent dramatically simplifies the fabrication and assembly processes. The continuous dielectric membrane with conductive coating can be manufactured as a single integrated component, eliminating the complex assembly steps required for mesh construction and tension maintenance.
Solution Approach 2:
The patent uses a flexible dielectric membrane with conductive coating that can be easily fabricated using thin-film deposition techniques. This approach allows the reflector to be manufactured as a lightweight, flexible structure that deploys naturally without requiring complex rigging or tensioning systems.
3Object-generated harmful factors
If tight tension is applied to woven wire mesh, then PIM is reduced, but the reflector shape must be maintained over wide temperature ranges
Solution Approach 1:
The patent eliminates the tensioning requirement by removing the woven wire mesh structure. The continuous conductive coating on the dielectric membrane maintains its reflective properties without requiring tight tension, thereby eliminating the need to maintain shape stability under thermal stress from tensioning.
Solution Approach 2:
The dielectric membrane material is selected for its thermal stability and dimensional consistency across wide temperature ranges. The composite structure of dielectric substrate with conductive coating provides both mechanical stability and electromagnetic functionality without requiring active tension maintenance.
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 passive intermodulation, allows for easy assembly and mass production, and maintains reflector shape integrity over temperature variations, while being cost-effective and suitable for UHF frequency ranges.
Implementation Method 1
The individual reflector gores are connected together to form a continuous reflective surface through capacitive coupling. The coupling is accomplished by overlapping adjacent gores so a dielectric material between the conductive layers of the overlapping gores forms a capacitor, allowing RF currents to flow from one gore to another with very little disturbance.
Data Source
AI summary
A passive intermodulation modulation reducing structure for a multicarrier reflector system, including a plurality of flexible reflector gores, each gore having a thin layer of conductive metal, a first layer of dielectric material laminated to one face of the conductive metal, and a second layer of dielectric material laminated to an opposite face of the conductive metal. Capacitive coupling joins the reflector's RF components. The structure can be a deployable parabolic reflector for a satellite antenna.