Segmented Cathode for Phase-Stable Planar Magnetron
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Solution Overview
Problem
Recirculating planar magnetrons face challenges in maintaining phase synchronization between upper and lower sections, leading to inefficient microwave power extraction due to weak coupling and frequency drift, especially when operating in pi mode.
Innovation Solution
The design includes a segmented mode control cathode with gaps aligned with cavities between vanes, allowing for enhanced coupling and phase stability by operating in either even or odd pi modes, which also reduces magnetic field requirements and precision control needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a solid cathode is used in recirculating planar magnetron, then the structure is simpler, but the coupling between upper and lower planar magnetron sections is weak leading to phase instability
Solution Approach 1:
The cathode is segmented into multiple sections with gaps between them, allowing electromagnetic coupling between upper and lower magnetron sections while maintaining structural simplicity. The gaps enable phase synchronization without requiring complex cathode structures.
2Device complexity
If traditional extraction methods are used, then the device structure is simpler, but microwave power extraction efficiency is reduced due to phase differences between sections
Solution Approach 1:
The extraction waveguides from upper and lower magnetron sections are merged into a common waveguide structure. This merging ensures that microwave power is extracted in-phase from both sections, maximizing extraction efficiency while maintaining relatively simple device structure.
3Productivity
If odd pi mode operation is used to achieve in-phase extraction, then power extraction efficiency improves, but magnetic field requirements and precision control increase
Solution Approach 1:
The invention changes the operational parameters by operating in even pi mode rather than odd pi mode. This parameter change achieves in-phase power extraction while reducing magnetic field requirements and relaxing precision control requirements, thereby improving productivity without increasing device 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 configuration achieves efficient power extraction by ensuring in-phase RF energy in waveguides, improving stability and reducing power requirements while maintaining the benefits of even pi mode operation.
Implementation Method 1
a cathode surrounded by an anode for creating a direct current (DC) or quasi-DC electric field (E) applied from the cathode to the anode region
Implementation Method 2
magnetic elements are placed on either side of the cathode and anode for creating a magnetic field (B) that is orthogonal to the electric field
Implementation Method 3
The cross product of these two fields results in electrons drifting in the direction shown by VExB
Implementation Method 4
This structure of vanes and cavities is often referred to as a 'slow wave structure' because of its tendency to slow the velocity of oscillatory electromagnetic (or 'EM') waves traveling along the structure to less than the speed of light
Implementation Method 5
electrons drifting in the direction shown by VExB along both sides of the cathode and then around the recirculation sections, which results in the creation of microwaves being formed in the cavities
Data Source
AI summary
A crossed field device for generating electromagnetic emissions includes an anode having a first slow-wave structure having a plurality of first vanes separated by cavities formed therebetween and a second slow-wave structure having a plurality of second vanes separated by cavities formed therebetween. At least one of the first vanes is laterally aligned with one of the second vanes. The first vanes are offset from the second vanes by an offset distance so that at least one of the first vanes is not laterally aligned with a second vane and at least one of the second vanes is not laterally aligned with a first vane. The device further includes a cathode disposed in a space located between first and second vanes. A magnetic element generates a magnetic field (B), which is oriented orthogonally to an electric field (E) formed by the anode and cathode to generate EM emissions.