Multilayer Coil Component Stray Capacitance Reduction

Solution Overview

Problem

Multilayer coil components for high-frequency devices face challenges in achieving high impedance while reducing stray capacitance, as existing solutions either compromise on frequency characteristics or require larger sizes due to the use of composite ferrite compositions that affect magnetic permeability and permittivity.

Innovation Solution

The design incorporates a component element assembly with a first region of magnetic material and a second region with a higher volume content of nonmagnetic material, specifically Si and Zn-based compounds, to reduce stray capacitance between the inner and outer conductors, ensuring large inductance and high impedance without impairing magnetic characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If composite ferrite composition containing magnetic material and nonmagnetic material is used to reduce stray capacitance, then stray capacitance is reduced, but impedance is reduced and favorable high-frequency characteristics cannot be ensured

Engineering Contradiction:

Improvestray capacitanceVSAvoidhigh-frequency characteristics

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The component element assembly is divided into a first region containing magnetic material and a second region containing nonmagnetic material. This segmentation allows the magnetic material region to maintain high impedance through large magnetic permeability while the nonmagnetic material region reduces stray capacitance, thereby resolving the contradiction between reducing stray capacitance and maintaining high-frequency characteristics.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the component element assembly are assigned different material compositions: the first region uses magnetic material with high magnetic permeability to ensure large inductance and high impedance, while the second region uses nonmagnetic material to reduce permittivity and stray capacitance. This local differentiation of material properties allows simultaneous optimization of both impedance and stray capacitance reduction.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If distance between inner conductor and outer conductor is increased to reduce stray capacitance, then stray capacitance is reduced, but component size increases

Engineering Contradiction:

Improvestray capacitanceVSAvoidcomponent size

Core Design Contradiction:

Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The invention changes the material parameter (permittivity) in the second region by using nonmagnetic material with low permittivity, which directly reduces stray capacitance without requiring an increase in the distance between conductors. This allows stray capacitance reduction while maintaining compact component dimensions.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If nonmagnetic material is added to reduce permittivity and stray capacitance, then stray capacitance is reduced, but magnetic permeability decreases and inductance is reduced

Engineering Contradiction:

Improvestray capacitanceVSAvoidmagnetic permeability

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The component element assembly is divided into a first region containing magnetic material and a second region containing nonmagnetic material. This segmentation allows the magnetic material region to maintain high impedance through large magnetic permeability while the nonmagnetic material region reduces stray capacitance, thereby resolving the contradiction between reducing stray capacitance and maintaining high-frequency characteristics.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the component element assembly are assigned different material compositions: the first region uses magnetic material with high magnetic permeability to ensure large inductance and high impedance, while the second region uses nonmagnetic material to reduce permittivity and stray capacitance. This local differentiation of material properties allows simultaneous optimization of both impedance and stray capacitance reduction.

Inventive Principle:

Principle #3Local quality

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 approach effectively reduces stray capacitance, maintains high-frequency characteristics, and achieves high impedance, while allowing for a more compact size, by optimizing the volume ratio of nonmagnetic material in the second region and magnetic material in the first region.

Implementation Method 1

a first region 8 in which the primary component is composed of a magnetic material... ensuring large inductance

Methodology Applied

Scientific EffectMagnetic permeability: Ferromagnetism

Implementation Method 2

setting the content in terms of a volume ratio of the nonmagnetic material contained in the second region to be greater than the volume content in the first region... reduce stray capacitance

Methodology Applied

Scientific EffectPermittivity: Dielectric Permittivity

Data Source

PatentUS11557429B2Multilayer coil component

Publication Date: 2023.01.17 MURATA MFG CO LTD

AI summary

A multilayer coil component includes an inner conductor, a component element assembly including the inner conductor, and outer conductors disposed at respective end portions of the component element assembly. The component element assembly has a first region in which the primary component is composed of a magnetic material and which may contain a nonmagnetic material and second regions which are disposed at respective end portions of the first region and which contain at least a nonmagnetic material. Each second region is disposed having a greater volume content of the nonmagnetic material than the first region such that, for example, the difference in the volume content results about 25% by volume or more. The coil portion of the inner conductor is embedded in the first region, and the length of the second region is greater than or equal to the length of the side-surface folded portion of the outer conductor.