Triple-Mode Resonator Coupling Windows for Wideband Waveguide Filters
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Solution Overview
Problem
Current multi-mode ceramic waveguide filters have limited bandwidth, lower Q-factor compared to metal cavity filters, and poor harmonic performance due to inadequate coupling methods, making them unsuitable for wideband radio applications and requiring larger sizes to improve Q-factor, which contradicts the need for smaller filters in 5G base stations.
Innovation Solution
A triple-mode resonator design with specific coupling window configurations on a dielectric material block with conductive overlays, allowing for improved Q-factor, flexible transmission zero settings, and enhanced harmonic performance by using annular and neighboring coupling windows to achieve predetermined parasitic zero points and wideband coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of the cavity is increased to improve Q-factor in single-mode CWG filters, then the value of Q-factor is improved, but the size of the filter increases which contradicts the basic design needs for reduction in size
Solution Approach 1:
The patent combines multiple resonant modes (TE011, TE101, TE012) within a single ceramic waveguide cavity to create a triple-mode resonator. This merging of multiple resonant functions into one cavity allows achieving high Q-factor equivalent to multiple separate cavities while significantly reducing the overall filter size and weight.
Solution Approach 2:
The triple-mode resonator is designed to support three different resonant modes simultaneously, making it a multi-functional component that replaces what would traditionally require three separate single-mode cavities. This universality allows the filter to achieve high Q-factor performance while maintaining compact dimensions suitable for 5G base station integration.
2Volume of moving object
If existing multi-mode CWG filters are used to reduce size, then the volume is reduced by 30%-50%, but the bandwidth is limited which cannot be applied to wideband radio
Solution Approach 1:
The patent introduces adjustable coupling mechanisms between the triple-mode resonator and external single-mode resonators, allowing dynamic control of coupling strength. This enables the filter to adapt its bandwidth characteristics while maintaining compact size, resolving the contradiction between small form factor and wideband operation.
Solution Approach 2:
The design allows modification of coupling parameters and resonator geometry to optimize both bandwidth and size. By changing coupling window configurations and resonator dimensions, the filter can be tuned for wideband performance while maintaining reduced volume suitable for 5G applications.
3Ease of manufacture
If blind holes or grooves are used for negative/capacitive coupling in single-mode CWG filters, then coupling is realized, but the coupling method is neither convenient for multi-mode coupling nor handy in coupling value control and transmission zero settings
Solution Approach 1:
The patent introduces external single-mode resonators as intermediary elements that couple to the triple-mode resonator through controlled coupling windows. This intermediary approach provides convenient control over coupling values and transmission zero settings, overcoming the limitations of direct blind hole or groove coupling methods.
Solution Approach 2:
The coupling windows are designed with adjustable parameters (size, position, configuration) that allow precise control of coupling strength and transmission zero locations. This parameter adjustability makes the coupling method both easy to implement and flexible for optimization, resolving the contradiction between manufacturing ease and operational control.
4Volume of moving object
If current multi-mode CWG filters are used, then size is reduced, but harmonic performance is very bad due to coupling method
Solution Approach 1:
The patent strategically positions parasitic zeros introduced by the coupling mechanism to suppress harmonic frequencies. By converting what would normally be harmful parasitic effects into beneficial harmonic rejection, the design achieves both compact size and improved harmonic performance simultaneously.
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 triple-mode resonator design significantly improves the Q-factor and insertion loss of waveguide filters, enables easier control of cross-coupling and transmission zero settings, and enhances harmonic performance, allowing for more compact and efficient filter designs suitable for wideband applications.
Implementation Method 1
A triple-mode resonator design with specific coupling window configurations on a dielectric material block with conductive overlays, allowing for improved Q-factor, flexible transmission zero settings, and enhanced harmonic performance
Implementation Method 2
When viewed in cross-section, a substantially closed region defined by an inner edge of each annular coupling window is positioned substantially within an electric field-concentrated area respectively associated with the first or second face of the main body
Data Source
AI summary
A triple-mode resonator includes a main body having a block of a dielectric material and an overlay of conductive material on the block; a first set of coupling windows provided in the overlay of conductive material on a first face of the main body to be coupled with a first single-mode resonator, and through which signals can be coupled into the main body; and a second set of coupling windows provided in the overlay of conductive material on a second face of the main body to be coupled with a second single-mode resonator, and through which signals can be coupled out of the main body, wherein the first and second sets of coupling windows each include an annular coupling window and a plurality of neighboring coupling windows located adjacent to the annular coupling window.