Dielectric Waveguide Filter Window Coupling for Harmonic Suppression
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Solution Overview
Problem
Current dielectric waveguide filters face challenges in effectively suppressing high-order modes and far-end harmonics, leading to poor performance and increased area requirements due to the need for additional filters or metal cavities, which compromise volume efficiency and performance.
Innovation Solution
The implementation of a dielectric waveguide filter with specific coupling structures, including window coupling structures and a feed structure, that target high-order modes by minimizing magnetic coupling and maximizing electrical coupling between resonant cavities, along with an adjacent cavity coupling spacer to reduce inter-cavity coupling, thereby enhancing suppression of high-order modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multi-order low-pass filters are added to suppress high-order modes, then far-end out-of-band suppression is improved, but device area and insertion loss increase
Solution Approach 1:
The patent extracts and targets the problematic high-order modes specifically through strategically positioned window coupling structures. By opening windows at locations where high-order mode fields are strongest, the filter selectively couples out harmful high-order modes while leaving the fundamental mode unaffected, achieving suppression without adding entire filter sections.
Solution Approach 2:
The window coupling structures act as intermediary elements between resonant cavities. These windows provide controlled coupling paths that specifically affect high-order mode transmission between cavities, serving as a mediator to suppress harmful modes without requiring additional filter components.
2Object-affected harmful factors
If metal cavities are cascaded with dielectric waveguide filters to improve far-end suppression, then harmonic suppression is improved, but volume efficiency deteriorates
Solution Approach 1:
The patent merges the harmonic suppression function directly into the dielectric waveguide filter structure by integrating window coupling structures into the existing resonant cavities. This combination eliminates the need for separate metal cavity sections while achieving equivalent or superior harmonic suppression, thereby maintaining volume efficiency.
Solution Approach 2:
The window coupling structures serve multiple functions simultaneously: they provide coupling between resonant cavities for fundamental mode transmission, and they selectively suppress high-order modes and harmonics. This multi-functionality replaces what would otherwise require separate dedicated suppression components, improving volume efficiency.
3Loss of energy
If window coupling structures are positioned to maximize fundamental mode coupling, then insertion loss is reduced, but high-order mode suppression deteriorates
Solution Approach 1:
The patent applies local quality by positioning window coupling structures at specific locations on resonant cavities where the fundamental mode has strong field intensity but high-order modes have different field distributions. This localized positioning creates different coupling characteristics for different modes: strong coupling for fundamental mode (low insertion loss) and selective coupling for high-order modes (effective suppression).
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 approach effectively suppresses high-order modes and far-end harmonics, improving the filter's performance while maintaining volume efficiency by reducing inter-cavity coupling and excitation of second high-order modes, thus enhancing overall suppression capabilities.
Implementation Method 1
minimizing magnetic coupling and maximizing electrical coupling between resonant cavities
Implementation Method 2
minimizing magnetic coupling and maximizing electrical coupling between resonant cavities
Implementation Method 3
a plurality of first resonant cavities and a plurality of second resonant cavities, wherein the plurality of first resonant cavities are connected to form upper resonant cavities, and the plurality of second resonant cavities are connected to form lower resonant cavities
Data Source
AI summary
A dielectric waveguide filter includes first resonant cavities, which are connected to form upper resonant cavities, and second resonant cavities, which are connected to form lower resonant cavities, wherein the upper and lower resonant cavities are correspondingly overlapped; each of the first resonant cavities has a first window coupling structure, wherein the first window coupling structure includes a first window opened at a position where the magnetic field distribution of a high-order mode in each of the first resonant cavities is the weakest, and/or a second window opened at a position where the electric field distribution of the high-order mode in each of the first resonant cavities is the strongest; and each of the second resonant cavities has a second window coupling structure corresponding to the first window coupling structure, and the first and second window coupling structures cooperate to eliminate the high-order modes of the dielectric waveguide filter.