Tunable Filter Single Rotating Rod Bandwidth Stability
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Solution Overview
Problem
Tunable bandpass filters require multiple tuning mechanisms to maintain constant absolute bandwidth over a tuning range, leading to bulkiness and high costs, while existing solutions offer limited tuning ranges and increased complexity.
Innovation Solution
A tunable filter design utilizing a single rotating rod to adjust the position of resonator posts, maintaining constant absolute bandwidth and insertion loss over a wide tuning range through inter-resonator coupling and input/output coupling structures, allowing for efficient frequency tuning in RF, microwave, and millimeter-wave applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple tuning mechanisms are used to maintain constant absolute bandwidth, then the bandwidth stability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines multiple tuning functions into a single tuning mechanism. Specifically, one tuning mechanism simultaneously adjusts the resonant frequencies of multiple resonators and maintains the constant absolute bandwidth, eliminating the need for separate tuning mechanisms for each resonator.
Solution Approach 2:
The single tuning mechanism is designed to perform multiple functions: it tunes the center frequency of the filter and simultaneously maintains the constant absolute bandwidth across the tuning range, making it a universal tuning solution for the entire filter system.
2Device complexity
If a single tuning mechanism is used, then the device complexity is reduced, but the ability to maintain constant absolute bandwidth deteriorates
Solution Approach 1:
The patent applies different geometric configurations to different resonators (e.g., different orientations of elliptical resonators) while using a single tuning mechanism. This local differentiation in resonator design enables the single mechanism to effectively control multiple resonators and maintain constant bandwidth.
Solution Approach 2:
The tuning mechanism works by changing geometric parameters (such as the position or orientation of tuning elements) of the resonators in a coordinated manner. By systematically varying these parameters, the mechanism maintains constant absolute bandwidth while tuning the filter frequency.
3Stability of the object's composition
If multiple tuning mechanisms are used, then the constant bandwidth is maintained, but the filter size and cost increase
Solution Approach 1:
The patent merges multiple tuning functions into a single tuning mechanism, which physically reduces the space required for tuning components. This consolidation eliminates the need for multiple separate tuning mechanisms, thereby reducing the overall filter volume.
4Stability of the object's composition
If multiple tuning mechanisms are used, then the constant bandwidth is maintained, but the manufacturing cost increases
Solution Approach 1:
The patent combines multiple tuning functions into a single tuning mechanism, which reduces the number of components that need to be manufactured and assembled. This consolidation directly lowers manufacturing costs by reducing part count and assembly complexity.
Solution Approach 2:
The single tuning mechanism is designed to perform multiple tuning functions simultaneously, making it a universal solution that replaces multiple specialized mechanisms. This multi-functionality reduces the overall system cost by eliminating redundant 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
The filter achieves a wide tuning range of at least 30% with minimal variations in bandwidth and insertion loss, reducing complexity and cost, and enhancing reliability for aerospace applications.
Implementation Method 1
tunable bandpass filters which have low loss (i.e. high-Quality Factor—high Q)
Implementation Method 2
The invention utilizes mechanism to change the gap between resonator post and tuning disk, thus changing the frequency response of the filter
Data Source
AI summary
The present invention is a high Q tunable co-axial filter, which maintains a constant absolute bandwidth and a constant Q over the tuning range. The present filter can be tuned by a single rotational mechanism irrespective of the filter order. A plurality of tunable resonators is aligned on a common filter axis. Each resonator has a casing having an inner wall and a cavity. The resonators are coupled by an iris opening. A pair of end plates completes the filter casing. A rotating rod placed on the common axis of the resonated, that has a tuning post attached to it, and each post located in each resonator, is used to tune the filter.