Multilayer Dielectric Filter Layout for Sintering Stress Relief
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Solution Overview
Problem
Manufacturing dielectric filters with multilayer dielectric resonators can result in structural defects due to differences in thermal expansion coefficients between regions of varying conductor density, leading to cracks, deformations, and reduced filtering characteristics.
Innovation Solution
The dielectric filter design includes a multilayer body with resonators arranged in a specific configuration, where lateral surfaces extend more in regions with conductors than in regions without, allowing for controlled shrinkage timing and reduced stress between these regions during manufacturing, thereby preventing structural defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If dielectric layers with varying conductor density are stacked together, then the resonator can be downsized and resonance frequency can be lowered, but structural defects including cracks and deformation occur due to difference in thermal expansion coefficient
Solution Approach 1:
The patent applies local quality by creating a protruding portion in the lateral surface of the multilayer body at the region where resonators are arranged. This local structural modification allows the region with resonators (higher conductor density) to have different dimensional characteristics than regions without resonators, compensating for the differential shrinkage and preventing cracks while maintaining the downsized resonator structure.
2Volume of moving object
If dielectric layers with varying conductor density are stacked together, then the resonator can be downsized and resonance frequency can be lowered, but deformation of internal structure such as bending or dimensional change of conductor occurs
Solution Approach 1:
The protruding portion creates a local dimensional difference that compensates for the shrinkage differential between high and low conductor density regions. This local structural feature prevents the conductor from bending or undergoing dimensional changes during the sintering process, while allowing the overall resonator to maintain its downsized configuration.
3Ease of manufacture
If lateral surfaces are made uniform across all regions, then manufacturing is simplified, but stress between regions with different conductor density increases causing structural defects
Solution Approach 1:
The patent introduces asymmetry by making the lateral surface protrude in the region where resonators are arranged, while keeping it recessed or at a different level in regions without resonators. This asymmetric design creates a stress-compensating structure that prevents cracks and deformation, while still being manufacturable through standard ceramic processing techniques.
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 configuration effectively prevents structural defects, ensuring the integrity and performance of the dielectric filter by minimizing stress and maintaining consistent conductor-dielectric adhesion, thus enhancing device strength and filtering characteristics.
Implementation Method 1
Some dielectric filters are manufactured by stacking together a plurality of dielectric layers with plate conductors disposed thereon, and compression-bonding or sintering them.
Implementation Method 2
a difference in thermal expansion coefficient between the portion where the conductor density is larger and a portion where the conductor density is smaller may cause structural defects
Data Source
AI summary
A filtering device includes a multilayer body and a plurality of resonators. The multilayer body includes a plurality of dielectric layers and has a rectangular parallelepiped shape. Each of the plurality of resonators is located inside the multilayer body and extends in a first direction orthogonal to a stacking direction of the multilayer body. The multilayer body includes lateral surfaces in a direction orthogonal to the first direction, and includes a region where the plurality of resonators are arranged and regions where the plurality of resonators are not arranged. The first and second lateral surfaces in the former region extend to a greater extent in the first direction than the first and second lateral surfaces in the latter regions.