Microwave Plasma Chamber Capacitive Ridges
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Solution Overview
Problem
Conventional microwave plasma sources have limitations in efficiently generating and sustaining plasmas due to restricted waveguide cavity widths, leading to reduced sensitivity in spectroscopic analysis and increased plasma cooling, which affects elemental analysis.
Innovation Solution
A microwave chamber with a capacitive loaded section that reduces cavity width while maintaining microwave propagation, using ridges to shape electromagnetic fields and improve impedance matching, allowing for more effective plasma generation and analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional waveguide cavity widths are used, then microwave propagation is maintained, but plasma generation efficiency is reduced and plasma cooling increases
Solution Approach 1:
The patent applies local quality by introducing ridges at specific locations within the waveguide cavity to create localized regions of enhanced electric field strength. These ridges are positioned to concentrate electromagnetic energy where plasma generation is most effective, allowing the cavity width to be reduced while maintaining plasma generation efficiency in the critical regions.
Solution Approach 2:
The patent changes the electromagnetic field distribution parameters by introducing ridges that modify the field pattern within the cavity. This alters the impedance characteristics and field concentration, enabling efficient plasma generation in a narrower cavity while maintaining the necessary microwave propagation properties.
2Measurement precision
If cavity width is reduced, then sensitivity of spectroscopic measurements is improved, but plasma cooling increases
Solution Approach 1:
The ridges create localized high-field regions that concentrate microwave energy precisely where needed for plasma generation. This localized energy concentration maintains plasma temperature and reduces cooling effects even in the narrower cavity configuration, thereby preserving measurement sensitivity.
Solution Approach 2:
The ridges are positioned periodically or at strategic intervals along the waveguide to create multiple zones of enhanced field strength. This periodic structure ensures continuous plasma generation and heating along the interaction region, compensating for the reduced cavity width and preventing plasma cooling.
3Ease of operation
If ridges are introduced to shape electromagnetic fields, then impedance matching is improved, but device complexity increases
Solution Approach 1:
Rather than modifying the entire chamber structure, the patent introduces ridges only in specific locations where field shaping is most effective for impedance matching. This localized approach improves impedance matching while minimizing the increase in overall device complexity.
Solution Approach 2:
The ridges act as intermediary structures that mediate between the microwave source and the plasma region. They provide a simple geometric feature that effectively shapes the electromagnetic fields and improves impedance matching without requiring complex tuning mechanisms or additional components.
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 enhances plasma generation efficiency, reduces plasma cooling, and improves elemental analysis by maintaining higher ionization states over a shorter distance, increasing the sensitivity of spectroscopic measurements.
Implementation Method 1
delivering microwave energy to a first end of the chamber and propagating the microwave energy through the chamber to a second end of the chamber
Implementation Method 2
The internal wall structure is configured to guide microwave energy... the ridges extend into the cavity from respective walls... capacitively load a region of the cavity near the ridges thereby increasing the electric fields of the microwaves in those regions
Implementation Method 3
Energy is coupled into a plasma forming gas in the plasma torch to sustain a plasma from microwaves in the microwave chamber
Implementation Method 4
sustain a plasma from microwaves in the microwave chamber. The plasma heats and excites the sample
Implementation Method 5
The plasma heats and excites the sample
Implementation Method 6
heating and ionizing the chemical sample... create ions of said elements
Implementation Method 7
atomized, ionised and/or excited so as to emit light characteristic of each element present in the sample
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
A microwave chamber for plasma generation. The microwave chamber comprises a launch structure at a first end of the microwave chamber to accommodate a microwave source for producing microwave energy and a termination section at a second end of the microwave chamber opposite the first end. The termination section is configured to substantially block propagation of the microwave energy from the second end of the chamber. The microwave chamber further comprises an internal wall structure for guiding the microwave energy received within the microwave chamber at the first end toward the second end and defines a cavity. The internal wall structure comprises an impedance matching section intermediate the first end and the second end, and a capacitive loaded section intermediate the impedance matching section and the second end, wherein the capacitive loaded section comprises at least one ridge extending along a longitudinal axis of the chamber. The microwave chamber defines a first opening extending through a first wall of the capacitive loaded section and a second opening extending through a second wall of the capacitive loaded section. The second wall is opposite the first wall. The first opening and second opening are configured to cooperate with one another to receive a plasma torch in the capacitive loaded section along an axis extending through first opening and second opening and substantially perpendicular to the longitudinal axis of the chamber.