Scheelite Microwave Dielectric Ceramic Material

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Solution Overview

Problem

Current microwave dielectric ceramic materials face challenges in achieving high dielectric constants, low loss, zero temperature coefficient of resonant frequency, and cost-effectiveness, particularly in meeting the requirements for miniaturization and integration in modern communication technologies.

Innovation Solution

A scheelite microwave dielectric ceramic material with the composition Bi(V1-xInx/3)MoO4, where 0.06≦x≦0.12, is developed using a low-temperature sintering method without sintering aids, allowing for adjustable temperature coefficients and high microwave performance, suitable for applications like radio frequency capacitors and filters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional microwave dielectric ceramic materials are used, then they can provide basic dielectric function, but they cannot simultaneously achieve high dielectric constant, low loss, zero temperature coefficient, and cost-effectiveness

Engineering Contradiction:
Improvemicrowave performanceVSAvoidmaterial composition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite material strategy by combining multiple metal elements (Bi, V, In, Mo, Nb) in specific ratios to create a scheelite-structured ceramic composite. This composite approach enables simultaneous achievement of high dielectric constant (70-75), low loss (Q×f > 5000 GHz), and adjustable temperature coefficient, while avoiding the need for precious metals and complex multi-phase composites.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes parameter changes by systematically varying the molar ratios of metal oxides (particularly In2O3 and Nb2O5 content represented by parameter x) to optimize microwave performance. By controlling the substitution parameter x in the formula Bi(V1-xInx/3Mo2x/3)MoO4, the temperature coefficient of resonant frequency can be adjusted while maintaining high dielectric constant and low loss characteristics.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If high dielectric constant materials are developed to meet miniaturization requirements, then component size can be reduced, but material loss increases and temperature stability deteriorates

Engineering Contradiction:
Improvecomponent sizeVSAvoiddielectric loss
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The scheelite-structured composite ceramic combines multiple metal elements to achieve high dielectric constant (70-75) while maintaining low dielectric loss (Q×f = 9230-10110 GHz). The synergistic effect of Bi, V, In, Mo, and Nb elements creates a material that enables component miniaturization without sacrificing loss performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

By optimizing the compositional parameter x (ratio of In2O3 and Nb2O5) within the range 0.06≦x≦0.12, the patent achieves the optimal balance between high dielectric constant and low dielectric loss. This parameter control ensures Q×f exceeds 5000 GHz while maintaining ∈r > 45, enabling miniaturized components with excellent loss performance.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If complex sintering aids are added to achieve desired microwave performance, then material performance improves, but preparation process complexity and cost increase

Engineering Contradiction:
Improvemicrowave performanceVSAvoidpreparation process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the need for complex sintering aids by utilizing the intrinsic low-melting-point characteristics of the scheelite-structured Bi-V-In-Mo-Nb oxide system. The material achieves complete sintering and phase formation at relatively low temperatures (780-840°C) without requiring additional sintering aid additives, thereby simplifying the preparation process while maintaining excellent microwave performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The scheelite-structured ceramic system exhibits self-sintering capability through the low melting points of its constituent oxides (Bi2O3, MoO3, V2O5). The material's own composition provides the necessary fluxing action during sintering, eliminating the need for external sintering aids and enabling a simpler, more cost-effective manufacturing process.

Inventive Principle:
Principle #25Self-service

4Reliability

If precious metals are used to achieve excellent microwave performance, then dielectric constant and quality factor improve, but material cost increases significantly

Engineering Contradiction:
Improvemicrowave performanceVSAvoidmaterial cost
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent replaces expensive precious metals with abundant, low-cost base metals (Bi, V, In, Mo, Nb) that can achieve comparable or superior microwave performance. The scheelite-structured ceramic made from these economical elements delivers ∈r = 70-75 and Q×f = 9230-10110 GHz at a fraction of the cost of precious metal-based dielectrics, making the material economically viable for large-scale communication applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The scheelite ceramic material achieves a high dielectric constant of 70-75, quality factor value of 9230-10110 GHz, and adjustable temperature coefficient of resonant frequency, meeting the performance criteria for various communication components while being environmentally friendly and cost-effective.

Implementation Method 1

A microwave dielectric ceramic is a new functional electronic ceramic material that has been developing rapidly in recent three decades, which features low loss, a small frequency temperature coefficient, a high dielectric constant

Methodology Applied
Scientific EffectMicrowave dielectric: Dielectric

Implementation Method 2

The scheelite microwave dielectric ceramic material may be obtained by means of low-temperature sintering without adding any sintering aid

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentUS9199882B2Scheelite microwave dielectric ceramic material and preparation method thereof
Publication Date: 2015.12.01 HUAWEI TECH CO LTD

AI summary

An embodiment of the present invention provides a scheelite microwave dielectric ceramic material. For example, a structure expression of the scheelite microwave dielectric ceramic material can be Bi(V1-xInx/3Mo2x/3)MoO4. In this embodiment, 0.06≦x≦0.12 An embodiment of the present invention further provides a method for preparing a scheelite microwave dielectric ceramic material.