Stacked Waveguide Band-Stop Filter for Wide-Range Tuning
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Solution Overview
Problem
Existing waveguide band-stop filters face limitations in tunability over a large frequency range due to dispersive coupling in extracted cavity filters and parasitic coupling in direct coupled filters, leading to bulky designs and narrow tuning ranges.
Innovation Solution
A waveguide band-stop filter arrangement with stacked cavity pairs connected via inductive and capacitive apertures, allowing for controlled electromagnetic couplings and tunability through complementary aperture arrangements with tuning screws, reducing parasitic coupling and enabling wide frequency range operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If extracted cavities are used for band-stop filtering, then the filter can be realized with conventional design, but the filter becomes bulky and tuning over large frequency range is complicated or impossible
Solution Approach 1:
The patent transitions from a conventional linear arrangement of cavities to a three-dimensional stacked configuration where cavities are arranged in multiple layers along the vertical dimension. This dimensional change allows compact filtering structures while maintaining the required electromagnetic coupling characteristics, resolving the contradiction between ease of manufacture and compact size.
2Ease of manufacture
If extracted cavities are used for band-stop filtering, then the filter can be realized with conventional design, but tuning over relatively large frequency band is complicated or impossible
Solution Approach 1:
The patent introduces adjustable coupling mechanisms between cavities that allow dynamic tuning of the filter characteristics. The coupling between stacked cavities can be adjusted to compensate for dispersive coupling effects, enabling continuous tuning over large frequency ranges while maintaining filter performance, thus resolving the contradiction between ease of manufacture and tunability range.
3Volume of moving object
If direct coupled cavities are used with broad wall coupling, then the filter is more compact, but the tuning range remains narrow due to identical coupling control limitation
Solution Approach 1:
The patent applies different coupling configurations to different cavities in the stack, with each cavity pair having independently controllable coupling characteristics. This local differentiation allows optimized coupling control for each stage, enabling wide tuning range while maintaining compact overall structure, resolving the contradiction between compact size and tuning range.
4Volume of moving object
If direct coupled cavities are used with narrow wall coupling, then the filter structure is compact, but strong parasitic coupling occurs between cavities that cannot be controlled
Solution Approach 1:
The patent transforms the parasitic coupling effect into a useful characteristic by strategically positioning and coupling cavities to generate desired reflection zeros. The coupling that was previously harmful is now controlled and utilized to achieve arbitrary placement of reflection zeros, converting the harmful effect into a beneficial design feature.
5Volume of moving object
If direct coupled cavities are used with narrow wall coupling, then the filter structure is compact, but arbitrary placement of reflection zeroes cannot be achieved
Solution Approach 1:
The patent introduces adjustable coupling mechanisms between cavities that allow dynamic control of the electromagnetic fields. By varying the coupling strength and phase between stacked cavities, arbitrary placement of reflection zeros can be achieved, providing full control over filter characteristics while maintaining compact structure.
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
The solution results in a compact, tunable band-stop filter with stable stop-band width and improved control over electromagnetic couplings, offering better wide-band performance and arbitrary placement of reflection zeroes.
Implementation Method 1
each cavity in the first pair, each first pair cavity, comprises a corresponding inductive first pair aperture arrangement that is adapted to connect the corresponding first pair cavity to the waveguide transmission line
Implementation Method 2
The first pair of cavities comprises a first capacitive aperture arrangement in the first common wall, mutually connecting the first pair cavities
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present disclosure relates to waveguide band-stop filter arrangement (1) adapted to be connected to a waveguide transmission line (2) at a filter interface (11), where the waveguide transmission line (2) is adapted for a main propagation extension (P). The band-stop filter (1) arrangement comprises a first pair of cavities (3, 4), where each cavity (3, 4) in the first pair, each first pair cavity (3, 4), comprises a corresponding inductive first pair aperture arrangement (5, 6) that is adapted to connect the corresponding first pair cavity (3, 4) to the waveguide transmission line (2). The first pair cavities (3, 4) are positioned adjacent each other along a stacking extension (S) perpendicular to the main propagation extension (P) such that they share a first common wall (7) and are adapted to be positioned adjacent the waveguide transmission line (2). The first pair of cavities (3, 4) comprises a first capacitive aperture arrangement (8) in the first common wall (7), mutually connecting the first pair cavities (3, 4).