Multilayer Bandpass Filter Via Coupling Impedance

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Solution Overview

Problem

Existing multilayer bandpass filters face challenges in miniaturization and design flexibility due to the need for precise impedance matching, which requires adjusting the distance between resonators, leading to increased component size and reduced design flexibility.

Innovation Solution

A multilayer bandpass filter design that includes a plurality of dielectric layers, capacitor electrodes, inductor electrodes, and via electrodes, allowing for adjustable impedance values by varying the thickness of dielectric layers and positioning of via coupling electrodes, enabling efficient magnetic field coupling and overlapping inductor loops for improved Q factors and reduced size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the distance between resonators is adjusted for impedance matching, then the impedance values are set to desired values, but the entire size of the component is increased

Engineering Contradiction:
Improveimpedance matching precisionVSAvoidcomponent size
Core Design Contradiction:
Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The patent transitions from adjusting resonator spacing in the horizontal plane to controlling impedance through vertical layering and via electrode positioning. The via electrodes extend through multiple dielectric layers, allowing impedance matching to be achieved in the vertical dimension rather than requiring increased horizontal separation between resonators.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the parameters controlled for impedance matching from resonator distance to via electrode characteristics (length, position, connection points). By varying the via electrode insertion depth and positioning within the stacked dielectric layers, the impedance can be precisely adjusted without changing the resonator spacing or overall component footprint.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the distance between resonators is changed for impedance matching, then the impedance values are adjusted, but the design flexibility is reduced

Engineering Contradiction:
Improveimpedance matching precisionVSAvoiddesign flexibility
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic adjustability through the via electrode configuration. The via electrodes can be positioned at different locations and extended to different depths within the dielectric layers, allowing the impedance to be adjusted for different design requirements without changing the fundamental resonator structure or spacing.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the impedance control function into multiple via electrodes that can be independently configured. Each via electrode can be optimized for specific impedance requirements, allowing different impedance values to be achieved by modifying individual via electrode parameters rather than redesigning the entire resonator arrangement.

Inventive Principle:
Principle #1Segmentation

3Reliability

If via coupling electrodes are used to connect via electrodes in adjacent LC parallel resonators, then magnetic field coupling is enhanced and Q factors are improved, but the device complexity increases

Engineering Contradiction:
ImproveQ factorVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The via coupling electrodes merge the grounding functions of adjacent resonators by connecting their via electrodes to a common ground reference. This unified grounding structure enhances magnetic field coupling between resonators and improves Q factors while the complexity is managed by using the same via electrode structure repeated across multiple resonators.

Inventive Principle:
Principle #5Merging (Combining)

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 allows for precise adjustment of impedance values, achieving a smaller size and higher design flexibility while maintaining high Q factors and efficient coupling between LC parallel resonators.

Implementation Method 1

via coupling electrode 23 electrically connecting via electrode 41 and via electrode 43 to each other

Methodology Applied
Scientific EffectMagnetic field coupling: Electromagnetic Induction

Data Source

PatentEP2312687B1Multilayer bandpass filter
Publication Date: 2015.02.11 MURATA MFG CO LTD
  • EP2312687B1 patent drawingFigure 1
  • EP2312687B1 patent drawingFigure 2
  • EP2312687B1 patent drawingFigure 3

AI summary

A first capacitor is formed between a first capacitor electrode and a ground electrode. A second capacitor is formed between a second capacitor electrode and the ground electrode. A first inductor is formed of first and second via electrodes and a first inductor eledrode. A second inductor is formed of third and fourth via electrodes and a second inductor electrode. Two LC parallel resonators, one of which includes the first inductor and the first capacitor and the other one of which includes the second inductor and the second capacitor, are formed. The second via electrode included in one of the LC parallel resonators and the fourth via electrode included in the other one of the LC parallel resonators are electrically connected to each other by a via coupling electrode.