Coaxial-to-Waveguide Transition with Movable Conductor for Impedance Tuning
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Solution Overview
Problem
The existing coaxial-to-waveguide transitions in traveling wave tubes face complexity and increased manufacturing costs due to the need for precise adjustment of characteristic impedance, which is challenging due to machining inaccuracies and dimensional variations, requiring multiple components and a cumbersome assembly process.
Innovation Solution
A coaxial-to-waveguide transition structure that includes a movable coaxial center conductor supported by a screw part, allowing for axial adjustment within the waveguide or connection part, with a dielectric for impedance adjustment near the insulating window member, preventing unintended impedance changes and arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple components with different dimensions are prepared and selected for assembly to achieve optimal impedance, then the characteristic impedance can be adjusted to desired optimal value, but the operation of adjusting impedance becomes complicated and manufacturing costs increase
Solution Approach 1:
The coaxial center conductor of exterior portion is made movable along the axial direction through a screw mechanism, allowing dynamic adjustment of its position. This enables continuous impedance tuning without requiring multiple discrete components of different dimensions, thereby simplifying assembly while maintaining precise impedance matching capability
Solution Approach 2:
The impedance is adjusted by changing the positional parameter of the coaxial center conductor of exterior portion along the axial direction. By moving this conductor to different positions, the characteristic impedance can be continuously tuned to optimal values without requiring multiple pre-manufactured components with different fixed dimensions
2Manufacturing precision
If multiple components with different dimensions are prepared and selected for assembly to achieve optimal impedance, then the characteristic impedance can be adjusted to desired optimal value, but manufacturing costs increase
Solution Approach 1:
Instead of manufacturing multiple discrete components with different dimensions, the invention uses a single coaxial center conductor that can be positioned dynamically. This reduces manufacturing complexity and costs while maintaining the ability to achieve optimal impedance through positional adjustment via the screw mechanism
Solution Approach 2:
A single coaxial center conductor of exterior portion serves multiple functions: it provides structural support, enables impedance matching, and allows for adjustable positioning. This multi-functionality eliminates the need for multiple specialized components, thereby reducing manufacturing costs while achieving precise impedance control
Data Source
AI summary
The present invention includes a waveguide for outputting radio frequency wave, a vacuum envelope provided with a slow-wave circuit, a coaxial connection part connecting the waveguide and the vacuum envelope, an insulating window member which is provided in the coaxial connection part and which hermetically seals a said of vacuum envelope and a said of waveguide, a coaxial center conductor of exterior portion with one end supported by the waveguide, and a coaxial center conductor of an interior portion with one end abutting on the slow-wave circuit and the other end connected to the coaxial center conductor of the exterior portion. The waveguide is provided with a screw part supporting the coaxial center conductor of the exterior portion movably in an axial direction of the coaxial center conductor of the exterior portion. An end portion of the coaxial center conductor of the exterior portion is connected to the end portion of the coaxial center conductor of the interior portion movably in the axial direction of the coaxial center conductor of the exterior portion.