Folded Waveguide Beam Hole Positioning for Bandwidth
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Solution Overview
Problem
The miniaturization of helix slow-wave circuits for high-frequency applications, such as terahertz waves, is hindered by the difficulty in shrinking the beam hole relative to the waveguide, leading to increased phase velocity frequency deviation and the appearance of stopbands, which limits the securement of a wide bandwidth for traveling-wave tubes.
Innovation Solution
A slow-wave circuit design featuring a folded waveguide with a beam hole arranged between the edge and center, rather than at the center, to reduce phase velocity slope and minimize stopbands, thereby securing a wider bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the beam hole is positioned at the center of the folded waveguide, then the structure is simple and symmetric, but the phase velocity frequency deviation increases and stopbands appear, limiting bandwidth
Solution Approach 1:
The beam hole is deliberately positioned asymmetrically within the folded waveguide structure, specifically at a location that is not the geometric center. This asymmetric positioning modifies the electromagnetic field distribution and phase velocity characteristics, eliminating stopbands and reducing frequency deviation while maintaining structural feasibility.
Solution Approach 2:
The invention applies local quality by creating a non-uniform structure where the beam hole position is specifically optimized at a particular location within the folded waveguide. This localized modification affects the electromagnetic interaction in that specific region, improving overall phase velocity flatness and bandwidth without requiring complete structural redesign.
2Volume of moving object
If the beam hole size is reduced to enable miniaturization, then the waveguide can be shrunk for high-frequency applications, but the ratio of beam hole to waveguide increases, causing frequency deviation and stopbands
Solution Approach 1:
The invention changes the positional parameter of the beam hole within the folded waveguide structure. By adjusting the beam hole's location rather than its size or the overall waveguide dimensions, the patent achieves miniaturization while maintaining controlled phase velocity characteristics and avoiding stopband formation.
3Power
If the beam hole ratio to waveguide is increased, then the electron beam interaction is enhanced, but the slope of phase velocity increases and stopbands appear
Solution Approach 1:
The asymmetric positioning of the beam hole optimizes the electromagnetic field interaction between the electron beam and the waveguide mode. This asymmetric configuration enhances the interaction efficiency for power transfer while simultaneously controlling the phase velocity slope to prevent stopband formation, resolving the contradiction between amplification capability and phase velocity control.
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 allows for a flatter frequency characteristic slope, reduces stopbands, and enhances the bandwidth of the traveling-wave tube, enabling improved amplification and frequency matching, with the beam hole's position fine-tuned to maintain effective interaction between the electron beam and high-frequency waves.
Implementation Method 1
a slow-wave circuit that delays the high frequency wave is necessary
Implementation Method 2
the high frequency wave is propagated in a helical waveguide
Implementation Method 3
an electron beam that is an amplification energy source
Data Source
AI summary
A slow-wave circuit is provided with a folded waveguide and a beam hole. The beam hole is arranged between an edge and a center in the direction of width of the folded waveguide. The beam hole is preferably arranged at an edge in the direction of width of the folded waveguide, at a position that does not protrude beyond the folded waveguide. The beam hole is preferably arranged at a position separated by a prescribed distance from the edge in the direction of width of the folded waveguide.