Interdigitated RF Filter Resonator Slot Coupling
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Solution Overview
Problem
Existing RF filters face challenges in achieving enhanced band pass performance and efficient slot coupling due to limitations in resonator configuration and interdigitation, which affect the placement of input and output nodes and impact electrical properties.
Innovation Solution
The implementation of a radio-frequency (RF) filter using an even number of ceramic coaxial resonators arranged in an interdigitated manner, with specific orientations to provide slot coupling between resonators, allowing for enhanced band pass performance by maintaining input and output nodes on a common side and optimizing electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resonators are arranged in traditional configurations, then the structure is simple, but the slot coupling between resonators is insufficient and band pass performance is not enhanced
Solution Approach 1:
The filter structure is segmented into multiple resonators (at least six) arranged in a specific interdigitated pattern, where odd-numbered resonators face one direction and even-numbered resonators face the opposite direction. This segmentation allows for optimized slot coupling between adjacent resonators while maintaining manageable structural complexity through modular arrangement.
Solution Approach 2:
The resonators are arranged in an interdigitated pattern extending in multiple dimensions rather than a simple linear or planar configuration. This multi-dimensional arrangement enhances the slot coupling between resonators and allows input and output nodes to be positioned on opposite sides, improving band pass performance without excessive complexity increase.
2Reliability
If input and output nodes are placed on opposite sides, then slot coupling is enhanced, but the reference plane consistency is compromised
Solution Approach 1:
Different regions of the filter are assigned different orientations: odd-numbered resonators (1st, 3rd, 5th, etc.) face one direction while even-numbered resonators (2nd, 4th, 6th, etc.) face the opposite direction. This local differentiation optimizes slot coupling in each region while maintaining overall reference plane consistency through the systematic alternating pattern.
Solution Approach 2:
The resonator array is segmented into alternating orientation groups, creating distinct coupling regions that maintain reference plane consistency within each segment while achieving enhanced overall slot coupling through the interdigitated arrangement of opposite-facing resonators.
3Reliability
If fewer resonators are used, then the device complexity is reduced, but the band pass performance and coupling coefficients are insufficient
Solution Approach 1:
The filter employs at least six resonators segmented into alternating orientation groups, where each resonator contributes to the overall band pass performance. This segmentation allows for optimized coupling coefficients between adjacent resonators while distributing the complexity across multiple standardized units, making the enhanced performance achievable without excessive complexity.
Solution Approach 2:
The resonators are arranged in an interdigitated multi-dimensional pattern rather than a simple linear sequence, which enhances the coupling coefficients and band pass performance. This spatial arrangement maximizes the electromagnetic interaction between resonators, achieving superior performance with a practical number of components.
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 significantly improves the filter's performance by reducing undesirable responses outside the band pass region, enhancing coupling coefficients, and maintaining a common reference plane for input and output connections, thereby achieving efficient RF signal filtering.
Implementation Method 1
The N resonators are configured to provide slot coupling between the first and the N-th resonators
Implementation Method 2
the first and second interdigitations being configured to provide enhancement of the slot coupling between the first and N-th resonators
Data Source
AI summary
Devices and methods related to multiple-pole ceramic resonator filters. In some embodiments, a radio-frequency (RF) filter can include a first coaxial resonator in a first orientation and having an input tab on a first side of the filter, and an N-th coaxial resonator in the first orientation and having an output tab on the first side of the filter. The RF filter can further include second and (N−1)th coaxial resonators, each in a second orientation opposite the first orientation to form first and second interdigitations with the first and N-th resonators, respectively. The RF filter can further include at least two coaxial resonators in the first orientation and coupled between the second and (N−1)th resonators. The N resonators can be slot coupled between the first and N-th resonators. The first and second interdigitations can be configured to provide enhancement of the slot coupling between the first and N-th resonators.