Multilayer LC Filter With Segmented Via Conductors
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Solution Overview
Problem
Multilayer LC filters with simple inductor configurations have inadequate Q values, leading to high internal resistances and increased insertion loss, which is undesirable for electronic devices, especially battery-driven mobile communication devices.
Innovation Solution
The multilayer LC filter design includes a rectangular-parallelepiped-shaped multilayer body with stacked dielectric layers, line-shaped conductor patterns, capacitor conductor patterns, and via conductors connected to both ends of the line-shaped conductor patterns, forming loop-shaped inductors and capacitors, with a specific arrangement of via conductors to reduce internal resistances and increase Q values while maintaining a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple inductor configuration is used in the multilayer LC filter, then the device complexity is reduced and manufacturing is easier, but the Q value of the inductor becomes inadequate and internal resistance increases
Solution Approach 1:
The inductor is segmented into multiple via conductors (first via conductor, second via conductor, third via conductor) connected in series to form a loop-shaped structure. This segmentation allows the inductor to achieve higher Q value and lower internal resistance while maintaining a compact multilayer structure, resolving the contradiction between simplicity and performance.
Solution Approach 2:
The inductor utilizes the vertical dimension of the multilayer structure by stacking via conductors across multiple dielectric layers. This three-dimensional configuration increases the effective inductance and Q value without increasing the planar footprint, thereby improving inductor performance without proportionally increasing device complexity.
2Ease of manufacture
If a simple inductor configuration is used, then the manufacturing process is simplified, but the internal resistance of the inductor increases leading to higher insertion loss
Solution Approach 1:
The inductor path is divided into multiple segments (via conductors and conductor patterns) distributed across different layers. This segmentation reduces the current density in each individual conductor, lowering resistive losses while maintaining manufacturability through standard multilayer PCB techniques.
Solution Approach 2:
Multiple conductor elements (via conductors and line-shaped/conductor patterns) are merged to form a complete loop-shaped inductor. This combined structure provides multiple parallel current paths that reduce overall internal resistance and insertion loss while being fabricated using conventional multilayer manufacturing processes.
3Reliability
If the filter size is increased to improve Q value and reduce insertion loss, then the inductor performance improves, but the compactness of the filter is compromised
Solution Approach 1:
The inductor structure transitions from a planar two-dimensional layout to a three-dimensional multilayer configuration. Via conductors connect different layers vertically, creating compact loop-shaped inductors that achieve high Q values and low insertion loss within a small footprint, effectively decoupling performance from size.
Solution Approach 2:
The loop-shaped inductor is nested within the multilayer body structure, with via conductors and conductor patterns integrated into the stacked dielectric layers. This nesting allows the inductor to occupy space efficiently in three dimensions rather than requiring large planar area, maintaining compact filter size while improving Q value.
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 reduces internal resistances, increases Q values of inductors, and decreases insertion loss, achieving improved frequency characteristics and broader bandwidth without increasing the filter's size.
Implementation Method 1
via conductors connected to both ends of line-shaped conductor patterns, forming loop-shaped inductors
Implementation Method 2
capacitors provided by capacitance between capacitor conductor patterns and ground conductor patterns
Implementation Method 3
LC resonators formed by inductors and capacitors connected to each other
Data Source
AI summary
A multilayer LC filter includes one via conductor on a second edge side and two via conductors on a fourth edge side that are connected to line-shaped conductor patterns of a first inductor, and two via conductors on the second edge side and one via conductor on the fourth edge side that are connected to line-shaped conductor patterns of a second inductor, and the third to fifth inductors also have this same relationship.