Band-pass filter shield partition for waveguide mode suppression
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Solution Overview
Problem
Band-pass filters designed for quasi-millimeter and millimeter wave bands face issues with unwanted resonance due to the waveguide mode, which degrades attenuation characteristics, especially since the resonance frequency of the lowest-order waveguide mode is close to the passband, and achieving strong capacitive coupling between adjacent resonators is challenging without compromising filter characteristics.
Innovation Solution
A band-pass filter design incorporating a shield with a partition that divides the space defined by the shield into smaller sections, allowing for magnetic coupling between non-adjacent resonators and capacitive coupling between adjacent ones, thereby increasing the resonance frequency of the lowest-order waveguide mode and creating attenuation poles in specific frequency regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield is added to prevent electromagnetic radiation, then radiation shielding is improved, but waveguide mode resonance occurs degrading attenuation characteristics
Solution Approach 1:
The shield is divided into multiple sections by inserting partitions between resonators. This segmentation breaks the continuous waveguide path, preventing waveguide mode resonance while maintaining electromagnetic radiation shielding. The partitions create discontinuities that block the propagation of waveguide modes without compromising the overall shielding effectiveness.
Solution Approach 2:
Partitions are introduced as intermediary elements between resonators within the shield. These partitions act as mediators that prevent the formation of waveguide modes by disrupting the electromagnetic field continuity, while allowing the shield to maintain its radiation shielding function. The partitions are strategically positioned to interfere with waveguide mode propagation paths.
2Reliability
If the space inside the shield is reduced to raise waveguide mode resonance frequency, then attenuation characteristic is improved, but coupling between resonators deteriorates
Solution Approach 1:
The internal space is segmented into multiple smaller regions by partitions, which effectively reduces the wavelength of waveguide modes and raises their resonance frequencies. This segmentation allows maintaining adequate coupling between resonators while preventing the formation of low-frequency waveguide modes that would degrade attenuation characteristics.
Solution Approach 2:
Partitions are inserted in the vertical dimension within the shield, creating a multi-level structure. This dimensional approach allows maintaining horizontal coupling between resonators while introducing vertical barriers that disrupt waveguide mode propagation, effectively raising the resonance frequency without compromising resonator coupling.
3Reliability
If partitions are added to raise waveguide mode resonance frequency, then attenuation characteristic is improved, but device complexity increases
Solution Approach 1:
The shield structure is segmented into modular sections with partitions positioned at specific locations. This segmentation achieves the desired attenuation improvement while keeping the overall structure manageable. The partitions are strategically placed only where needed to disrupt waveguide modes, avoiding unnecessary complexity in regions where it is not required.
Solution Approach 2:
Partitions are introduced locally at specific positions within the shield where waveguide mode propagation is most problematic, rather than uniformly throughout. This local quality approach improves attenuation characteristics by targeting specific resonance issues while minimizing the overall increase in device complexity and maintaining simplicity in other regions.
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 design enhances the attenuation characteristics by preventing deterioration in the frequency region above the passband and achieving steep changes in insertion loss, while maintaining strong coupling between resonators, thus improving the filter's performance in both passband vicinity regions.
Implementation Method 1
configured so that electromagnetic coupling is established between every two of the resonators adjacent to each other in circuit configuration
Implementation Method 2
the shield and a dielectric material inside the shield constitute a structure similar to a waveguide, thereby generating at least one propagation mode for electromagnetic waves
Implementation Method 3
The resonance frequency of the lowest-order waveguide mode varies depending on the shape of the space defined by the shield
Data Source
AI summary
A band-pass filter includes a main body, five resonators, a shield, and a partition. The main body is formed of a dielectric. The partition is formed of a conductor. The five resonators are configured so that capacitive coupling is established between every two of the resonators adjacent to each other in circuit configuration. Each of the five resonators includes a resonator conductor portion. A first stage resonator and a fifth stage resonator are magnetically coupled to each other although not adjacent to each other in circuit configuration. The partition extends to pass between the respective resonator conductor portions of the first stage resonator and the fifth stage resonator, and is electrically connected to the shield.