Dielectric Ceramic Materials for Microwave Resonators

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Solution Overview

Problem

Current dielectric ceramic materials for electronic components, particularly in microwave devices, face challenges in achieving optimal electrophysical characteristics such as high relative dielectric constant, high Q factor, and small temperature coefficient, while maintaining low temperature sintering and reduction resistance.

Innovation Solution

The development of a dielectric ceramic material with the formula Ba12M'(28+2x/3)Ti(54-x-y)M''xGe y O162, where M' is a rare earth element and M'' is a metal, with specific fabrication methods involving blending precursor compounds, promoting reaction, comminuting, forming, sintering, and adding dopants to enhance dielectric properties and crystalline morphology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional dielectric ceramic compositions are used, then the relative dielectric constant can be achieved, but the Q factor and temperature coefficient cannot be simultaneously optimized

Engineering Contradiction:
Improveelectrophysical characteristicsVSAvoidtemperature coefficient control
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs a composite ceramic system comprising multiple oxide components (BaO, TiO2, RE2O3, M''2O3, M'''2O3) that work synergistically. The base composition Ba12M'(28+2x/3)Ti(54-x-y)M''xM''''yO162 provides high dielectric constant, while rare earth elements (La, Nd, Sm, Gd, Y) and metal dopants (Mg, Ni, Co) enable independent optimization of Q factor and temperature coefficient through controlled substitution at specific lattice sites.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent systematically varies compositional parameters including rare earth element selection, dopant concentrations (x, y values), and sintering conditions to achieve target electrophysical properties. By adjusting the ratios of M'', M'''' and their concentrations, the invention independently controls Q factor, temperature coefficient, and dielectric constant to meet specific application requirements.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If high dielectric performance is achieved through complex compositions, then electrophysical characteristics improve, but manufacturing complexity and sintering difficulty increase

Engineering Contradiction:
Improvedielectric constant and Q factorVSAvoidsintering process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs preliminary calcination of precursor mixtures before final sintering to pre-form the complex perovskite-phase ceramic structure. This two-stage process (calcination at 900-1100°C followed by sintering at 1200-1400°C) simplifies the manufacturing by breaking down the complex one-step sintering into manageable stages, ensuring complete reaction and phase formation while reducing final sintering temperature requirements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses intermediate precursor compounds (carbonates, oxalates, or hydroxides of Ba, RE, Ti, and dopants) that facilitate uniform mixing and controlled decomposition during calcination. These intermediaries act as mediators that enable complete incorporation of all elements into the final ceramic structure, ensuring stoichiometric accuracy and homogeneous microstructure even for complex multi-component compositions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If standard sintering temperatures are used, then processing is simplified, but reduction resistance and phase stability are compromised

Engineering Contradiction:
Improvesintering temperatureVSAvoidreduction resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent utilizes controlled atmosphere parameters during sintering (oxidizing, neutral, or reducing conditions) to stabilize specific crystal phases and enhance reduction resistance. By adjusting atmospheric composition and sintering temperature within optimized ranges, the invention achieves phase stability and desired microstructure while maintaining lower processing temperatures compared to conventional methods.

Inventive Principle:
Principle #35Parameter changes

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 results in dielectric ceramic materials with improved electrophysical characteristics, including high relative dielectric constant, high Q factor, and controlled temperature coefficient, suitable for microwave devices, while ensuring low temperature sintering and reduction resistance.

Implementation Method 1

dielectric ceramic materials with improved electrophysical characteristics, including high relative dielectric constant, high Q factor

Methodology Applied
Scientific EffectDielectric polarization: Dielectric

Implementation Method 2

sintering, and adding dopants to enhance dielectric properties

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP2957547B1Dielectric ceramic materials and associated methods
Publication Date: 2019.07.31 SKYWORKS SOLUTIONS INC
  • EP2957547B1 patent drawingFigure 1
  • EP2957547B1 patent drawingFigure 2
  • EP2957547B1 patent drawingFigure 3A~3B

AI summary

Ceramic dielectric materials that can be utilized as electronic components, such as dielectric resonators are disclosed. The material can have a formula Ba12M'(28+a/3)Ti(54-a-b)M"aGebO162, wherein M' is at least one rare earth element selected from the group consisting of lanthanum, neodymium, samarium, gadolinium, and yttrium, M" is at least one element selected from the group consisting of aluminum, gallium, chromium, indium, scandium, and ytterbium, 0 ≤ a ≤ 6, and 0 ≤ b ≤ 3. The ceramic dielectric material can also have a formula Ba12M'(28+2x/3)Ti(54-x-y)M"'xGeyO162, wherein M' is at least one rare earth element selected from the group consisting of lanthanum, neodymium, samarium, gadolinium, and yttrium, M"' is at least one metal selected from the group consisting of magnesium, zinc, nickel, and cobalt, 0 ≤ x ≤ 3, and 0 ≤ y ≤ 3. One or more aspects of the present invention pertain to methods of fabricating a dielectric component. Methods of synthesizing the disclosed ceramic dielectric materials are also disclosed.