LTCC Dielectric Composition for Near-Zero Resonance Drift
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Solution Overview
Problem
Existing LTCC microwave dielectric materials have high dielectric constants and non-near-zero temperature coefficients of resonance frequency, which are undesirable for high-frequency communication applications.
Innovation Solution
A composite LTCC microwave dielectric material comprising Ba5Si8O21, (MgxCaySrzBa1-x-y-z)WO4, and Ba—B—Si glass, where the glass reduces the sintering temperature and adjusts the temperature coefficient of resonance frequency to near-zero.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ba5-xLaxTixNbxO15 is complexed with BaCuB2O5 and BaWO4 to obtain a low-temperature firing microwave dielectric ceramic, then the Qf value is higher than 10000 GHz and the temperature coefficient of resonance frequency is near-zero, but the dielectric constant becomes high (35-45)
Solution Approach 1:
The patent uses a composite material system consisting of Ba5Si8O21, (MgxCaySrzBa1-x-y-z)WO4, and Ba-B-Si glass. This composite approach allows combining materials with different properties: Ba5Si8O21 provides low dielectric constant, while (MgxCaySrzBa1-x-y-z)WO4 provides negative temperature coefficient to compensate for the positive coefficient of Ba5Si8O21, achieving near-zero overall temperature coefficient without sacrificing low dielectric constant property
Solution Approach 2:
The patent adjusts the chemical composition parameters by varying the ratios of Ba5Si8O21 and (MgxCaySrzBa1-x-y-z)WO4, and modifying the glass content (2-15 wt%). By changing these compositional parameters, the patent achieves optimal balance between low dielectric constant and near-zero temperature coefficient, while also reducing sintering temperature through glass addition
2Quantity of substance
If Ba5Si8O21 is used as a base material to achieve low dielectric constant, then the dielectric constant is reduced, but the temperature coefficient of resonance frequency becomes non-near-zero
Solution Approach 1:
The patent applies the counterweight principle by combining Ba5Si8O21 (with positive temperature coefficient) with (MgxCaySrzBa1-x-y-z)WO4 (with negative temperature coefficient). The negative temperature coefficient material acts as a counterweight to compensate for the positive coefficient of Ba5Si8O21, achieving near-zero overall temperature coefficient while maintaining the low dielectric constant advantage of Ba5Si8O21
3Loss of energy
If traditional LTCC materials are used for high-frequency applications, then signal transmission loss is high and signal transmission speed is reduced, but changing materials may affect manufacturing complexity
Solution Approach 1:
The patent optimizes the sintering temperature parameter by adding Ba-B-Si glass with low melting point, reducing the sintering temperature to 850-900°C. This parameter change enables low-temperature processing while achieving the desired material properties (low dielectric constant and near-zero temperature coefficient), thereby reducing signal transmission loss without significantly increasing manufacturing complexity
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 material achieves a low dielectric constant and a near-zero temperature coefficient of resonance frequency, making it suitable for high-frequency communication and radiofrequency applications.
Implementation Method 1
Ba5Si8O21, having a positive temperature coefficient of resonance frequency and a low dielectric constant, complexes with (MgxCaySrzBa1-x-y-z)WO4, which has a negative temperature coefficient of resonance frequency
Implementation Method 2
The sintering temperature of the system is lowered by the addition of Ba—B—Si glass, which has a low melting point
Data Source
AI summary
An LTCC microwave dielectric material, including the following components: a Ba5Si8O21+(1−a) (MgxCaySrzBa1-x-y-z)WO4+Ba—B—Si glass; wherein 0.4≤a≤0.8, 0≤x≤1, 0≤y≤1, 0≤z≤1. By adjusting the amounts of Ba5Si8O21 and (MgxCaySrzBa1-x-y-z)WO4, the temperature coefficient of resonance frequency can be adjusted to nearly zero. The material is suitable for the fields of high-frequency communication and radiofrequency. Also disclosed is a method for preparing the LTCC microwave dielectric material.