Post-Wall Waveguide Filter Layout for Easier Resonator Tuning
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Solution Overview
Problem
The design of resonator-coupled filter devices is complex due to the need for optimizing resonator areas and coupling window sizes, which are mutually dependent, making it difficult to achieve uniform effective areas and desired transmission characteristics.
Innovation Solution
A post-wall waveguide configuration with n electromagnetically coupled resonators, where resonators R1 to R(n−1)/2 have control posts with decreasing shortest distances to the narrow wall, and resonators R(n+1)/2+1 to Rn have control posts with increasing shortest distances, allowing for simpler design by adjusting control post positions to match effective areas and coupling window sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If various sizes of coupling windows are used to obtain desired transmission characteristics, then the bandwidth and resonance frequencies can be controlled, but the effective areas of the resonators become non-uniform and deviate from design values
Solution Approach 1:
The invention introduces control posts at specific locations within resonators to locally adjust electromagnetic field distribution. By positioning control posts at different distances from the resonator center, the effective area of each resonator can be precisely controlled to compensate for variations caused by coupling windows, thereby maintaining uniform effective areas while achieving desired transmission characteristics
Solution Approach 2:
The invention changes the parameter of control post position to adjust the effective area of resonators. By varying the distance of control posts from the resonator center, the electromagnetic coupling and effective area are modified, allowing independent control of resonance frequencies and effective areas to resolve the contradiction between transmission characteristics and area uniformity
2Adaptability or versatility
If the areas of resonators and sizes of coupling windows are optimized together, then desired transmission characteristics can be achieved, but the design process becomes complex due to mutual dependence
Solution Approach 1:
The invention separates the design optimization into independent stages: first determining coupling window sizes based on desired bandwidth, then using control posts to adjust effective areas for precise resonance frequency control. This segmentation eliminates the need for simultaneous optimization of resonator areas and coupling window sizes, significantly simplifying the design process while achieving desired transmission characteristics
Solution Approach 2:
The invention performs preliminary determination of coupling window sizes before finalizing resonator dimensions. By first establishing the coupling windows to achieve target bandwidth, then adding control posts to adjust effective areas, the design process follows a logical sequence that reduces complexity compared to simultaneous optimization approaches
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 simplifies the design process by eliminating the need for precise optimization of resonator areas and coupling window sizes, enabling the creation of filter devices with desired characteristics, such as ultra-narrow-band band pass filters, while reducing the complexity of design parameters.
Implementation Method 1
The two adjacent resonators are electromagnetically coupled together via the coupling window
Implementation Method 2
A change in position of the control post makes it possible to change a resonance frequency of a corresponding resonator
Data Source
AI summary
A filter device having desired characteristics is easily designed. The filter device includes a post-wall waveguide functioning as a resonator group including five congruent resonators (R1 to R5). The resonators (R1, R2) include therein respective control posts (CP1, CP2), and a shortest distance (di) from the control post (CPi) to a narrow wall of the resonator (Ri) satisfies d1>d2. The resonators (R4, R5) include therein respective control posts (CP4, CP5), and a shortest distance (dj) from the control post (CPj) to a narrow wall of the resonator (Rj) satisfies d4<d5.