Waveguide Bandstop Filter Resonator Coupling
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Solution Overview
Problem
Conventional bandstop filters face limitations in achieving strong couplings between resonator chambers and waveguides due to the upper limit of diaphragm cross-sectional area, restricting their filtering capabilities.
Innovation Solution
Incorporating resonator bodies with resonance frequencies above the waveguide limit frequency, combined with inductive or capacitive discontinuities like iris diaphragms and recesses in the waveguide, to enhance coupling strength and achieve desired filter characteristics, including reflexion zeros at finite frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the free cross section area of the diaphragm is increased to strengthen coupling between resonator chambers and waveguide, then the coupling strength is improved, but the area is limited by the chamber cross section which restricts further coupling enhancement
Solution Approach 1:
The patent transitions from two-dimensional diaphragm coupling to three-dimensional resonator body coupling by placing resonator bodies at specific positions within the waveguide cross-section. This spatial arrangement in multiple dimensions enables stronger electromagnetic interaction without being constrained by diaphragm area limitations.
Solution Approach 2:
The invention changes the fundamental coupling parameter from diaphragm area to resonator body position and dimensions. By adjusting the location, size, and orientation of resonator bodies within the waveguide, coupling strength can be optimized without the area constraints that limit diaphragm-based coupling.
2Strength
If resonator bodies with resonance frequencies above the waveguide limit frequency are used, then stronger couplings and more flexible filter designs are achieved, but the device complexity increases
Solution Approach 1:
The filter is divided into multiple resonator bodies that can be independently positioned and tuned. Each resonator body acts as a separate coupling element, allowing the overall filter response to be synthesized through the combination of individual resonator contributions, thereby achieving complex filtering characteristics through modular segmentation.
Solution Approach 2:
Resonator bodies serve as intermediary elements between the waveguide modes. These resonators with frequencies above the waveguide cutoff act as mediators that enable strong coupling interactions while transforming the electromagnetic field distribution, thereby achieving desired filter characteristics through controlled intermediate resonance.
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 allows for stronger couplings and more flexible filter designs, enabling effective blocking and transmission bands, suitable for applications like frequency duplex microwave transmission lines, with reduced manufacturing complexities and improved performance.
Implementation Method 1
at least one resonator body having a resonance frequency above the limit frequency of the waveguide
Implementation Method 2
a hollow waveguide interconnecting the two
Implementation Method 3
inductive or capacitive discontinuity located in the waveguide
Implementation Method 4
inductive or capacitive discontinuity located in the waveguide
Data Source
AI summary
In a bandstop filter having an input port (2; 3), an output port (3; 2) and a waveguide (1, 1′) connecting the two ports, at least one resonator body (4, 5; 4′ 5) is located in the waveguide (1, 1′), which resonator body has resonance frequency above the limit frequency of the waveguide (1; 1′).