Microwave Filtering Structure with Conductive Pillars
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing three-plate microwave filtering structures suffer from transmission losses and distortion in frequency response due to imperfections in transitions and low quality factor substrates, leading to spurious responses outside the passband.
Innovation Solution
A microwave filtering structure with two dielectric layers separated by a conductive layer, featuring optimized transition devices that minimize standing wave ratios and TE10 mode excitation, and conductive pillars connecting ground planes without coupling, allowing seamless microstrip to stripline mode transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If three-plate structures are used for microwave filtering, then electromagnetic shielding and compact dimensions are improved, but transmission losses in the dielectric increase
Solution Approach 1:
The patent extracts and eliminates the harmful TE10 mode by introducing conductive pillars that specifically target and suppress this parasitic mode, while preserving the beneficial TEM mode propagation in the three-plate structure
Solution Approach 2:
Conductive pillars are introduced as intermediary elements between the ground planes to suppress the TE10 mode without interfering with the main TEM mode signal transmission, thereby reducing spurious responses while maintaining low transmission losses
2Ease of manufacture
If standard microstrip to stripline transitions are used, then ease of integration is improved, but distortion and spurious responses in frequency response increase
Solution Approach 1:
The transition devices are locally optimized with specific geometric parameters and conductive pillar placements to minimize TE10 mode excitation at the transition zones, while maintaining standard manufacturing processes for overall integration
Solution Approach 2:
The patent optimizes specific geometric parameters of the transition devices and conductive pillar configurations to minimize standing wave ratios and TE10 mode coupling, thereby reducing distortion while maintaining ease of integration
3Device complexity
If conventional filter structures are used, then simplicity of design is improved, but parasitic responses outside the passband increase
Solution Approach 1:
The patent converts the potentially harmful TE10 mode that naturally arises in three-plate structures into a beneficial suppression mechanism by strategically placing conductive pillars that eliminate spurious responses while maintaining structural simplicity
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 solution provides a distortion-free and parasitic response over a wide frequency band, significantly enhancing filtering performance and reducing production costs through standard microwave circuit techniques.
Implementation Method 1
the propagation takes place in Transverse Electro Magnetic (TEM) mode
Implementation Method 2
the three-plate structure has its own electromagnetic shielding and therefore does not radiate
Implementation Method 3
each allowing passage from a microstrip mode to a stripline mode and vice-versa
Implementation Method 4
at least two conductive pillars perpendicular to the plane of the structure, located laterally element relative to the filter as close as possible to a main axis of the structure, without there being any coupling with the filter and connecting the upper and lower ground planes
Data Source
Figure 1~2
Figure 3
AI summary
Microwave-frequency filtering structure (20) characterized in that it comprises: - two dielectric layers (21, 23) separated by a conducting layer (22), the conducting layer (22) being etched in the pattern of a filter, - the upper and lower exterior faces of the stack of two dielectric layers (21, 23) being covered over the larger part of their surface by a conducting plane constituting ground planes of the structure (20), - said ground planes being interlinked by a metallization of the periphery of the structure (20), except in the vicinity of microwave-frequency ports, - two identical devices (24, 25), one of them being an input transition device (24) and one being an output transition device (25), each allowing the passage from a microstrip mode to a stripline mode and vice versa, configured in such a way that the geometry of the transition device (24, 25) is optimized so as to minimize the standing wave ratios at the ports of the filter (22), and to also minimize the excitation and the coupling of the TE10 mode, - at least two conducting pillars (27) perpendicular to the plane of the structure (20) and situated as close as possible to its principal axis, without there being any coupling with the filter (22), and linking the upper and lower ground planes.