Dielectric Waveguide Plasma Source Without Inner Conductor Breakdown
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Solution Overview
Problem
Conventional plasma generating apparatuses face issues such as dielectric breakdown, heat accumulation, and high manufacturing costs due to their design, which limits the ability to generate high-output plasma and reduces the possibility of downsizing.
Innovation Solution
The apparatus employs a conductive waveguide with a dielectric member extending along its axis, eliminating the inner conductor to prevent dielectric breakdown and enhance plasma output, while incorporating a dielectric constant buffer to maintain impedance matching and facilitate heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional coaxial tube structure with an inner conductor is used, then the apparatus can guide microwaves, but dielectric breakdown easily occurs when microwaves of large output are injected
Solution Approach 1:
The invention removes the inner conductor from the coaxial tube structure, extracting the problematic component that limited the insulation distance. This allows the outer shield radius to be reduced while maintaining sufficient insulation distance for high-power microwave operation without dielectric breakdown
Solution Approach 2:
The invention changes the structural parameter by eliminating the inner conductor, which fundamentally alters the microwave guidance mechanism. This parameter change enables both high plasma output and prevention of dielectric breakdown by allowing optimized outer shield dimensions
2Reliability
If the outer shield radius is increased to ensure sufficient insulation distance, then dielectric breakdown is prevented, but the apparatus size increases
Solution Approach 1:
By removing the inner conductor, the invention eliminates the space-consuming component that forced a larger outer shield radius. This extraction allows the apparatus to be compact while maintaining adequate insulation distance for preventing dielectric breakdown
3Device complexity
If a conventional coaxial structure with limited contact area is used, then the structure is simple, but heat accumulates inside the apparatus
Solution Approach 1:
The invention segments the heat dissipation function by providing multiple heat dissipation fins on the outer shield, distributing the thermal management across multiple surfaces. This segmentation enables effective heat dissipation while maintaining structural simplicity
Solution Approach 2:
The invention adds a radial dimension for heat dissipation by incorporating fins that extend outward from the outer shield. This dimensional addition creates large surface area for heat exchange with the surrounding environment, effectively preventing heat accumulation
4Productivity
If the outer surface of the dielectric body is tapered to improve impedance matching, then plasma generation efficiency improves, but manufacturing cost increases
Solution Approach 1:
Instead of tapering the dielectric body outer surface, the invention inverts the approach by providing heat dissipation fins on the outer shield. This inverted strategy achieves plasma generation efficiency through improved thermal management rather than geometric tapering, reducing manufacturing complexity
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 design allows for enhanced plasma output and reduced apparatus size by preventing dielectric breakdown and heat accumulation, while maintaining efficient impedance matching and cost-effectiveness.
Implementation Method 1
a first dielectric member extending along a main axis of the waveguide in an interior of the waveguide, connected to a microwave supply cable that supplies microwaves, and configured to propagate the supplied microwaves to the first end side
Implementation Method 2
a second dielectric member arranged so as to close the opening and configured to generate plasma with use of the microwaves propagated by the first dielectric member
Data Source
AI summary
Provided are an outer conductor 29 as a conductive waveguide having an opening 34 at a first end, a first dielectric 31 extending along a main axis of the outer conductor 29 in an interior of the outer conductor 29, connected to a microwave supply cable 5 that supplies microwaves, and configured to propagate the supplied microwaves to the first end side, and a second dielectric 33 arranged so as to close the opening 34 and configured to generate plasma with use of the microwaves propagated by the first dielectric 31.