Corrugated Copper Waveguides via Additive-Free Pulse Electroforming
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Solution Overview
Problem
Traditional fabrication methodologies for high-frequency microwave waveguides lack precision and practicality in producing small features required for higher frequency ranges, leading to imperfections that impact signal transmission and achievable gradients, particularly with oxygen-free copper which is difficult to machine due to its high ductility and tool wear issues.
Innovation Solution
An electroforming process using a pulse/pulse reverse process to deposit copper onto an aluminum mandrel with sub-millimeter accuracy, avoiding additive-induced contamination, and allowing for the removal of the mandrel to produce high-purity, corrugated copper waveguides with sub-micron surface finishes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional machining methods are used on oxygen-free copper, then the waveguide can be fabricated, but the machining difficulty increases significantly due to high ductility and tool wear
Solution Approach 1:
The patent replaces mechanical machining with electroforming, an electrochemical process. Copper is deposited onto an aluminum mandrel through controlled electrochemical reactions, eliminating the need for mechanical cutting tools and avoiding the tool wear and machining difficulty associated with oxygen-free copper's high ductility.
Solution Approach 2:
The patent uses a composite approach where an aluminum mandrel serves as the temporary substrate, and copper is electroformed onto it. The aluminum-copper combination during fabrication allows easy mandrel removal after copper deposition, solving the manufacturing difficulty while maintaining the final copper waveguide's required properties.
2Ease of manufacture
If conventional electroforming with additives is used, then copper deposition can be achieved, but purity is reduced due to additive-induced contamination
Solution Approach 1:
The patent extracts and removes harmful additives from the electroforming process. By using a clean electrolyte solution without conventional additives, the process eliminates contamination sources while still achieving successful copper deposition through optimized electrochemical parameters and pulse plating techniques.
Solution Approach 2:
The patent changes the electroforming parameters, specifically using pulse plating with controlled current density and time intervals. This allows precise control of copper deposition without requiring additives, maintaining both processability and high copper purity for vacuum-compatible waveguides.
3Manufacturing precision
If machining is used to create small features for high frequency ranges, then the waveguide can be fabricated, but precision is insufficient leading to imperfections that impact signal transmission
Solution Approach 1:
The patent replaces mechanical machining with electroforming to create small features. The electrochemical deposition process naturally conforms to the mandrel's geometry, producing smooth surfaces and precise corrugation features without the imperfections, tool marks, and dimensional inaccuracies that plague mechanical machining at small scales.
Solution Approach 2:
The patent achieves local quality control by using pulse plating techniques that allow different deposition rates and characteristics in different regions. The electrolyte flow and current distribution are optimized to ensure uniform, high-purity copper deposition in critical areas, producing the sub-micron surface finishes needed for high-frequency signal transmission.
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 process achieves robust, high-conductivity waveguides with improved mechanical properties and reduced ohmic losses, enabling operation at frequencies up to 300 GHz with minimal machining required, and maintaining high purity without the need for additives.
Implementation Method 1
an electroforming process where modulating the electric field with pulse-based waveforms during electroforming enable the ability to accurately confer structural features
Implementation Method 2
by a scalable electroforming approach where modulating the electric field with pulse-based waveforms during electroforming enable the ability to accurately confer structural features exhibiting sub-millimeter dimensionally accuracies
Implementation Method 3
followed by dissolution of the mandrel
Data Source
AI summary
A method of manufacturing a corrugated copper microwave waveguide comprising placing a mandrel with external corrugations in an electrolyte bath substantially devoid of brighteners, accelerators, or levelers and including copper ions, sulfuric acid, chloride, and polyethylene glycol. The mandrel is placed proximate a copper anode in the bath. One or more waveforms are applied to the mandrel and anode to control electrodeposition distribution of copper to the mandrel rather than controlling the electrolyte bath chemistry. The mandrel and the resulting electroformed waveguide are removed from the electrolyte bath and the mandrel is excised (e.g., dissolved) resulting in a microwave waveguide with internal corrugations. Substantially devoid of additives (brighteners, accelerators, and/or levelers) generally means not having to repeatedly meter in additives during the electroforming process.