Dielectric Filter Side-Via Layout for Smaller Footprint and Stable Q
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Solution Overview
Problem
The existing dielectric filters occupy a large area on a mounting board due to the projection size of resonance blind vias, which reduces the single-cavity Q value and hampers miniaturization, while also affecting filtering efficiency and remote suppression capabilities.
Innovation Solution
The dielectric filter design places resonance blind vias on opposite side surfaces of the dielectric body and uses coupling through holes and slots on the top surface to implement negative and positive coupling between resonators, reducing the height projection area without affecting the single-cavity Q value, thereby minimizing the on-board footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If resonance blind vias are located on the upper surface of the dielectric body, then the dielectric filter occupies a large area on the mounting board, but the single-cavity Q value is maintained
Solution Approach 1:
The patent moves the resonance blind vias from the upper surface (2D plane) to the side surfaces (vertical dimension) of the dielectric body. This dimensional transition allows the filter to maintain its single-cavity Q value while significantly reducing the on-board footprint, as the vias now occupy vertical space rather than horizontal mounting board area
2Area of stationary object
If the projection size of the dielectric body in the axial direction is reduced, then the on-board footprint is reduced, but the single-cavity Q value decreases
Solution Approach 1:
By relocating resonance blind vias to side surfaces and using vertical coupling through holes, the patent decouples the relationship between projection area and Q value. The single-cavity Q value is now maintained through vertical coupling mechanisms rather than horizontal projection size
Solution Approach 2:
The patent changes the structural parameters of coupling by introducing coupling through holes with specific depths and positions on side surfaces. This allows optimization of coupling strength independently from the projection area, enabling small footprint while maintaining Q value
3Adaptability or versatility
If coupling blind vias with greater depth are used for negative coupling, then coupling between resonators is achieved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the coupling function into separate coupling through holes positioned on side surfaces, distinct from resonance blind vias. This segmentation allows each component to be optimized independently, simplifying manufacturing compared to deep coupling blind vias that require precise integration with resonance structures
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 achieves miniaturization of the dielectric filter without compromising the single-cavity Q value, improves remote suppression, and reduces insertion loss by eliminating the need for low-pass traces, enhancing filtering efficiency.
Implementation Method 1
negative coupling is implemented between the first resonator and the second resonator via the first connection part
Implementation Method 2
Signal energy conversion between electric and magnetic fields may be performed between two adjacent resonators, to implement coupling between the two resonators
Data Source
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AI summary
Embodiments of this application provide a dielectric filter and a communication apparatus. The dielectric filter includes a dielectric body, and the dielectric body is provided with at least a first resonance blind via located on a first side surface and a second resonance blind via located on a second side surface. The first resonance blind via and the dielectric body surrounding the first resonance blind via form a first resonator, and the second resonance blind via and the dielectric body surrounding the second resonance blind via form a second resonator. A top surface of the dielectric body is provided with a first coupling through hole and a second coupling through hole, a first connection part is provided between the first coupling through hole and the second coupling through hole, and negative coupling is implemented between the first resonator and the second resonator via the first connection part. An on-board footprint of the dielectric filter can be reduced without reducing a single-cavity Q value of the resonator, thereby effectively implementing miniaturization of the dielectric filter. In addition, a remote suppression effect can be improved, and a loss of the dielectric filter can be reduced.