Cavity Filter Resonator Branches for Remote Harmonic Suppression
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Solution Overview
Problem
Existing cavity filters face issues of high cost, increased insertion loss, and inability to achieve miniaturization due to the addition of low-pass filters for harmonic suppression, which also complicate assembly and occupy space.
Innovation Solution
A cavity filter design incorporating input and output resonators with branches of a quarter wavelength length to suppress remote harmonics, eliminating the need for additional low-pass filters, resulting in a simpler structure, reduced material cost, and improved performance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-pass filters are added to suppress remote harmonics, then harmonic suppression performance is improved, but device complexity increases
Solution Approach 1:
The patent merges the harmonic suppression function into the existing cavity filter structure by adding resonant branches to the resonant rods. This integration eliminates the need for separate low-pass filters, achieving harmonic suppression without increasing overall device complexity. The resonant branches are coupled with the resonant rods to form a unified structure that performs both filtering and harmonic suppression.
Solution Approach 2:
The resonant rods in the cavity filter are designed to serve multiple functions: they provide the primary resonant function for signal filtering and simultaneously suppress remote harmonics through their coupled resonant branches. This multi-functionality eliminates the need for dedicated harmonic suppression components, resolving the contradiction between performance improvement and complexity increase.
2Reliability
If low-pass filters are added to suppress remote harmonics, then harmonic suppression performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines the harmonic suppression function with the existing cavity filter structure, eliminating the need for separate low-pass filter components. This merger reduces the total number of parts, simplifies the manufacturing process, and lowers material and assembly costs while maintaining effective harmonic suppression.
Solution Approach 2:
The resonant rods are designed to perform dual functions: primary signal filtering and remote harmonic suppression. This multi-functionality reduces the bill of materials and manufacturing complexity, directly addressing the cost increase issue while achieving the desired harmonic suppression performance.
3Reliability
If low-pass filters are added to suppress remote harmonics, then harmonic suppression performance is improved, but insertion loss increases
Solution Approach 1:
The patent integrates harmonic suppression directly into the cavity filter's resonant structure, allowing for optimized coupling between the resonant branches and rods. This integrated design enables better control of energy distribution, reducing unnecessary losses that would occur with separate low-pass filter stages while maintaining effective harmonic suppression.
4Reliability
If low-pass filters are added to suppress remote harmonics, then harmonic suppression performance is improved, but the filter size increases
Solution Approach 1:
The patent merges the harmonic suppression function into the existing cavity volume by adding resonant branches to the resonant rods. This integration utilizes the existing space efficiently, avoiding the need for additional volume that would be required for separate low-pass filter components, thus preventing filter size increase.
Solution Approach 2:
The resonant branches are nested within or coupled to the existing resonant rod structure, effectively utilizing the available space within the cavity filter. This nesting approach allows harmonic suppression functionality to be embedded within the existing footprint, preventing any increase in overall filter volume.
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 design effectively suppresses remote harmonics while reducing material costs and simplifying the manufacturing process, enabling miniaturization and lightweight construction.
Implementation Method 1
The resonant rod is arranged at the bottom of the cavity and has a cylindrical shape. The cover plate cooperates with the tuning screw to adjust the coupling frequency of the cavity filter.
Implementation Method 2
The length of the first branch and the length of the second branch are a quarter wavelength of a resonant frequency of the cavity filter
Data Source
AI summary
A cavity filter includes a housing, an input resonator and an output resonator. The input resonator includes a first sheet-like resonant body, an input end extending outward from one side of the first sheet-like resonance body and a first branch extending outward from the first sheet-like resonance body and/or the input end, and the input end extends out of the housing through the input through hole. The output resonator includes a second sheet-like resonant body, an output end extending outward from one side of the second sheet-like resonance body, and a second branch extending outward from the second sheet-like resonance body and/or the output end, and the output end extends out of the housing through the output through hole. The lengths of the first branch and the second branch are both a quarter wavelength of a resonant frequency of the cavity filter.