Multilayer Band-pass Filter Electrode Segmentation
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Solution Overview
Problem
The reduction in thickness of dielectric layers in multilayer band-pass filters leads to unintended electromagnetic field coupling between resonator capacitor electrodes, preventing the achievement of desired frequency characteristics.
Innovation Solution
A compact band-pass filter design where LC resonators are arranged perpendicular to the stacking direction, with one capacitor electrode grounded on one main surface and the others on the opposite surface, minimizing electromagnetic field coupling by increasing the distance between line electrodes and using loop inductors to enhance capacitance without size increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of dielectric layers is reduced to achieve size reduction and low profile, then the compactness of the band-pass filter is improved, but unintended electromagnetic field coupling occurs between resonator capacitor electrodes via the ground electrode
Solution Approach 1:
The patent divides the resonator capacitor electrodes into multiple segments stacked in the thickness direction. By segmenting the electrodes and introducing dielectric layers between them, the electromagnetic field coupling path is interrupted, preventing unintended coupling while maintaining the reduced thickness design.
Solution Approach 2:
The patent transitions from a planar electrode configuration to a three-dimensional stacked configuration. By arranging capacitor electrodes in multiple layers along the thickness direction and connecting them via via electrodes, the design achieves compactness in the horizontal plane while managing electromagnetic coupling through the vertical dimension.
2Length of stationary object
If the distance between the ground electrode and LC resonators is decreased to achieve low profile, then the thickness of the band-pass filter is reduced, but electromagnetic field coupling between resonator capacitor electrodes increases
Solution Approach 1:
The patent introduces dielectric layers as intermediary elements between the ground electrode and the resonator capacitor electrodes. These dielectric layers act as mediators that reduce the direct electromagnetic coupling while allowing the overall structure to maintain a low profile thickness.
Solution Approach 2:
The patent applies different dielectric materials with varying permittivity values in different regions of the structure. By optimizing the local dielectric properties in specific areas, the electromagnetic field distribution is controlled to minimize unwanted coupling while maintaining compact dimensions.
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 prevents unnecessary electromagnetic field coupling, reduces external noise interference, and maintains excellent frequency characteristics, allowing for a compact and efficient band-pass filter with improved out-of-band attenuation.
Implementation Method 1
a via inductor defined by a plurality of via electrodes (154, 160, 264, 268, 354, 360) which are connected to each other and which penetrate through the dielectric layers (114 to 119)
Implementation Method 2
a capacitor (C1 to C3) including a pair of capacitor electrodes (133, 134, 233, 234, 332, 355) provided on the dielectric layers (113 to 119)
Implementation Method 3
LC resonators (Q1 to Q3) arranged in a direction perpendicular or substantially perpendicular to a stacking direction of the multilayer body
Data Source
AI summary
A capacitor of a certain LC resonator, among multiple LC resonators in a band-pass filter, is arranged at a side of one main surface in a stacking direction of a multilayer body of the band-pass filter and the capacitors of the remaining LC resonators are arranged at a side of the other main surface in the stacking direction of the multilayer body. One of a pair of capacitor electrodes of the capacitor of the certain LC resonator is grounded. The one capacitor electrode that is grounded covers at least the plurality of LC resonators, as viewed from the stacking direction of the multilayer body.