Multilayer Filter Device Reducing Electromagnetic Coupling
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Solution Overview
Problem
Filter devices with components close to each other on a circuit substrate experience increased signal power loss and degraded attenuation characteristics due to electromagnetic coupling, which affects their performance.
Innovation Solution
A filter device design incorporating a multilayer board with series and parallel passive elements, open stubs, and strategically arranged electrodes to minimize electromagnetic interference, including a series wire connecting input and output terminals, parallel wires connecting to a reference electrode, and open stubs with opposing portions to form capacitors without conductive interposition, thereby reducing parasitic capacitance and enhancing filter characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If components are arranged close to one another to reduce filter size, then device size is reduced, but signal power loss increases and attenuation characteristics are degraded due to electromagnetic coupling
Solution Approach 1:
The patent transitions from a planar two-dimensional layout to a three-dimensional multilayer structure. Components are distributed across multiple wiring layers (first, second, and third wiring layers) separated by dielectric layers, allowing compact arrangement while maintaining spatial separation to reduce electromagnetic coupling between components.
Solution Approach 2:
Dielectric layers are introduced as intermediary materials between conducting wires and components across different wiring layers. These dielectric layers act as electromagnetic shields that reduce coupling effects while allowing electrical connections through vias, thus maintaining both compactness and signal integrity.
2Reliability
If additional reactance elements are added to improve attenuation characteristics, then filter performance is improved, but device complexity and size increase
Solution Approach 1:
Existing structural elements (wiring layers, dielectric layers, vias, and component mounting positions) are designed to serve multiple functions. The multilayer board structure itself provides both mechanical support and electromagnetic isolation, while via holes provide both electrical connections and additional isolation pathways, reducing the need for separate dedicated isolation components.
Solution Approach 2:
The patent combines multiple functions into integrated structures. The multilayer board integrates mechanical support, electrical connectivity, and electromagnetic isolation functions. Components are mounted on the board and electrically connected through the layered structure, merging what would traditionally require separate isolation elements into the fundamental board architecture.
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 effectively suppresses degradation in filter characteristics by reducing electromagnetic coupling, allowing for improved signal attenuation and increased harmonic frequency band attenuation without additional reactance elements, while minimizing device size.
Implementation Method 1
The parallel wire and the open stub include a first opposing portion and a second opposing portion, respectively, that are opposed to each other without necessarily having a conductor interposed therebetween
Data Source
AI summary
A filter device includes: a multilayer board including a first wiring layer where a first terminal and a second terminal are connected, a second wiring layer including a reference electrode, a third wiring layer between the first wiring layer and the second wiring layer, a first dielectric layer between the first wiring layer and the third wiring layer, and a second dielectric layer between the second wiring layer and the third wiring layer; a series passive element provided to a series wire; a parallel wire connecting the series wire and the reference electrode; a parallel passive element provided to the parallel wire; and an open stub provided to the third wiring layer. The parallel wire and the open stub include a first opposing portion and a second opposing portion, respectively, that are opposed to each other without a conductor interposed therebetween.