Dielectric Filter Layout With Capacitive Cross-Coupling Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dielectric filters using multilayer dielectric resonators face challenges in achieving desired attenuation characteristics due to insufficient coupling of resonators, leading to overlapping attenuation pole frequencies and suboptimal performance.
Innovation Solution
A dielectric filter design with a laminate body and capacitive electrodes that allow for individual adjustment of cross-coupling between non-adjacent resonators, enhancing the adjustment range of frequency for multiple attenuation poles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If resonators are arranged in a compact layout to reduce device size, then device area is reduced, but coupling between resonators becomes insufficient and attenuation pole frequencies overlap
Solution Approach 1:
A capacitive electrode is introduced as an intermediary element between non-adjacent resonators (specifically between the first and third resonators) to enable direct capacitive coupling. This mediator allows sufficient coupling strength to be achieved without requiring the resonators to be placed close together, thus preventing attenuation pole frequency overlap while maintaining a compact overall device footprint.
Solution Approach 2:
The coupling mechanism transitions from relying solely on spatial proximity (one-dimensional arrangement) to utilizing electromagnetic field coupling through an intermediate capacitive electrode. This adds another dimension to the coupling approach, allowing non-adjacent resonators to be effectively coupled without requiring linear adjacency, thereby resolving the contradiction between compact layout and sufficient coupling.
2Manufacturing precision
If resonators are spaced further apart to improve coupling control, then coupling adjustment precision is improved, but device area increases
Solution Approach 1:
The capacitive electrode serves as a controllable intermediary that provides precise coupling adjustment capability. By modifying the geometry, position, or properties of this intermediate element, the coupling strength between non-adjacent resonators can be precisely controlled without requiring large spacing between the resonators themselves, thus achieving both precision and compactness.
Solution Approach 2:
The coupling characteristics are controlled by changing parameters of the capacitive electrode (such as its area, position, or dielectric properties) rather than relying solely on the spacing between resonators. This parameter change approach enables fine-tuned coupling control within a compact device area, resolving the contradiction between precision and size.
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 design improves attenuation characteristics by allowing precise adjustment of attenuation pole frequencies, achieving greater than 60 dB attenuation at each pole and providing steeper attenuation profiles.
Implementation Method 1
The first capacitive electrode couples the first resonator and the third resonator
Implementation Method 2
The first capacitive electrode allows individual adjustment of cross-coupling between two resonators that are not adjacent
Implementation Method 3
a first resonator, a second resonator, and a third resonator... The first to third resonators are between the first plate electrode and the second plate electrode
Data Source
AI summary
A filter device includes a laminate body including dielectric layers, plate electrodes, resonators, shield conductors, and a capacitive electrode. The plate electrodes are spaced apart from each other in a lamination direction in the laminate body. The resonators are between the plate electrodes and extend in a first direction. The shield conductors are on side surfaces, respectively, that are orthogonal or substantially orthogonal to the first direction in the laminate body, and connected to the plate electrodes. The resonators are provided in a second direction orthogonal or substantially orthogonal to the lamination direction and the first direction in the laminate body. The resonators each include a first end connected to the shield conductor and a second end spaced apart from the shield conductor. The capacitive electrode couples the resonators.