Crystallized Glass Composition for Temperature-Stable 10 GHz Dielectrics
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Solution Overview
Problem
Existing crystallized glasses for high-frequency devices exhibit a positive temperature dependence of the relative dielectric constant, leading to performance variations with temperature changes, necessitating a material with stable dielectric properties across a wide temperature range.
Innovation Solution
A crystallized glass with a specific composition, including SiO2, Al2O3, B2O3, TiO2, and controlled alkali metal oxide content, that maintains a small change in relative dielectric constant between -50 ppm/°C and 50 ppm/°C at 10 GHz, incorporating rutile crystals to stabilize dielectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional crystallized glass is used, then dielectric properties can be improved, but relative dielectric constant increases with temperature leading to performance variation
Solution Approach 1:
The patent changes the chemical composition parameters of the glass, specifically controlling alkali metal oxide content to 3.0% or less and adjusting the ratio of alkaline earth metal oxides (MgO: 5-15%, CaO: 10-20%, SrO: 5-15%, BaO: 5-15%). This compositional parameter adjustment resolves the contradiction by achieving both improved dielectric properties and temperature stability of the relative dielectric constant.
Solution Approach 2:
The patent creates a composite crystallized glass material containing multiple crystal phases (rutile, anatase, brookite, or TiO2) dispersed in a glass matrix with specific composition. This composite structure provides both excellent dielectric properties and temperature stability, resolving the technical contradiction between dielectric performance and temperature dependence.
2Ease of manufacture
If alkali metal oxide content is increased to improve glass properties, then ease of manufacture is improved, but dielectric stability over temperature range deteriorates
Solution Approach 1:
The patent optimizes the alkali metal oxide content parameter to 3.0% or less, which is lower than conventional glasses. This parameter change maintains ease of manufacture while significantly improving dielectric stability over temperature, resolving the contradiction between manufacturability and dielectric reliability.
Solution Approach 2:
The patent introduces local quality control by specifying different content ranges for various alkaline earth metal oxides (MgO: 5-15%, CaO: 10-20%, SrO: 5-15%, BaO: 5-15%) while keeping total alkali metal oxide content low. This localized compositional control achieves both manufacturability and dielectric stability.
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 solution provides a crystallized glass with stable dielectric properties over a wide temperature range, ensuring consistent performance in high-frequency applications by minimizing changes in the relative dielectric constant.
Implementation Method 1
a crystallized glass which has a value calculated according to the following equation (A) of −50 ppm (/° C.) to 50 ppm (/° C.) when a rate of change ΔDk (/° C.) in a relative dielectric constant at 10 GHz due to a temperature is expressed by the following equation (A)
Data Source
AI summary
The present invention relates to a crystallized glass, having a value calculated according to the following equation (A) of −50 ppm (/° C.) to 50 ppm (/° C.) when a rate of change ΔDk (/° C.) in a relative dielectric constant at 10 GHz due to a temperature is expressed by the following equation (A), and having a total content of an alkali metal oxide R2O of 3.0% or less in terms of molar percentage based on oxides,[Math. 1]ΔDk=(relative dielectric constant at 10 GHz and 60° C.)-(relative dielectric constant at 10 GHz and -20° C.)(relative dielectric constant at 10 GHz and 20° C.)×(60° C. - (-20° C.))(A)