Forsterite-Calcium Strontium Titanate Dielectric Ceramic Composition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current dielectric ceramic compositions for high-frequency applications lack optimal Q values, temperature stability, and mechanical strength, particularly in mobile communication devices, where high-frequency radio waves are used.
Innovation Solution
A dielectric ceramic composition comprising forsterite and calcium strontium titanate with specific molar ratios, combined with Li-containing glass and additional subcomponents like CuO, B2O3, Al2O3, and MnO, to achieve improved Q values, temperature stability, and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dielectric ceramic compositions are used, then manufacturing is simpler, but Q value and temperature stability are insufficient
Solution Approach 1:
The patent uses a composite ceramic system combining forsterite (Mg2SiO4) and calcium strontium titanate (Ca1-xSrxTiO3) in specific ratios, where forsterite provides high Q value and low dielectric constant, while calcium strontium titanate adjusts the temperature coefficient of resonance frequency. This composite approach achieves satisfactory Q value (Q×f ≥ 1500) and temperature stability (τf between -30 to +30 ppm/℃) that neither material can achieve alone.
Solution Approach 2:
The patent optimizes specific compositional parameters: forsterite content at 84.0-92.5 parts by mole, calcium strontium titanate at 7.5-16.0 parts by mole, (Sr+Ca)/Ti ratio at 1.03-1.20, and Ca/(Sr+Ca) ratio at 0.60-1.00. These precise parameter controls enable simultaneous achievement of high Q value, appropriate dielectric constant (6.0-8.0), and satisfactory temperature coefficient of resonance frequency.
2Ease of manufacture
If glass content is increased to improve sinterability, then manufacturing is easier, but Q value decreases
Solution Approach 1:
The patent precisely controls glass content at 2-10 parts by mass relative to 100 parts by mass of main component and subcomponent (excluding Li-containing glass), and specifies Li2O content at 10-30% by mass within the glass. This controlled glass addition provides sufficient sinterability for low-temperature co-fired ceramic (LTCC) processing while minimizing the negative impact on Q value, achieving Q×f ≥ 1500.
Data Source
AI summary
Provided is a dielectric ceramic composition comprising a main component of forsterite and calcium strontium titanate. A content ratio of forsterite in the main component is from 84.0 to 92.5 parts by mole, and a content ratio of calcium strontium titanate is from 7.5 to 16.0 parts by mole. (Sr+Ca)/Ti in the calcium strontium titanate is from 1.03 to 1.20 in terms of a molar ratio. With respect to a total of 100 parts by mass of the main component and a subcomponent except for Li-containing glass, from 2 to 10 parts by mass of Li-containing glass is added. The Li-containing glass includes Al2O3 in an amount of from 1% by mass to 10% by mass.