Superconductive Filter Thermal Stress Mitigation via Intermediate Substrate
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Solution Overview
Problem
Superconductive filters with stacked resonator patterns face issues with crack formation due to thermal contraction differences between the package and dielectric substrate, leading to increased transmission loss and reduced reliability.
Innovation Solution
Incorporating an intermediate substrate with a contraction degree between that of the package and dielectric substrate, and using flexible sheets to reduce shear stress and prevent cracking during cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the package, intermediate substrate, and dielectric substrate are cooled from room temperature to critical temperature, then the superconductive filter achieves operational temperature, but thermal contraction differences cause crack formation in the dielectric substrate
Solution Approach 1:
An intermediate substrate is introduced between the package and the dielectric substrate. This intermediate substrate has a thermal contraction coefficient that is intermediate between those of the package and the dielectric substrate, thereby reducing the thermal stress transmitted to the dielectric substrate during cooling and preventing crack formation.
Solution Approach 2:
The thermal contraction coefficients of the package, intermediate substrate, and dielectric substrate are carefully selected and graded. By changing the material parameters (thermal contraction coefficients) in a stepped manner from the package to the dielectric substrate, the thermal stress during temperature change is minimized, preventing cracks while maintaining operational temperature.
2Reliability
If a dielectric substrate is overlapped on the disk-type resonator pattern, then current concentration is reduced, but the structure becomes more complex and requires additional components
Solution Approach 1:
The intermediate substrate serves multiple functions simultaneously: it acts as a structural support, provides thermal management, reduces thermal stress during cooling, and helps distribute current density. By merging these functions into a single component rather than using separate elements, the overall structural complexity is reduced while achieving current concentration reduction.
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 effectively reduces the occurrence of cracks in the dielectric substrate, maintaining the superconductive filter's performance and reliability by minimizing thermal stress, thereby enhancing the filter's operational stability and efficiency.
Implementation Method 1
an intermediate substrate disposed between an inner surface of the package and the superconductive filter substrate, and thermally coupling the package and the superconductive filter substrate
Implementation Method 2
when the package, the intermediate substrate, and the dielectric substrate are cooled from room temperature to a critical temperature of the resonator patterns
Data Source
AI summary
A superconductive filter includes a superconductive filter substrate having a dielectric substrate and a plurality of resonator patterns formed on a surface of the dielectric substrate, the plurality of resonator patterns including a superconductive material; a package accommodating the superconductive filter substrate; and an intermediate substrate disposed between an inner surface of the package and the superconductive filter substrate, and thermally coupling the package and the superconductive filter substrate wherein a difference between a degree of contraction of the intermediate substrate and the degree of contraction of the dielectric substrate is smaller than a difference between the degree of contraction of the dielectric substrate and the degree of contraction of the package, when the package, the intermediate substrate, and the dielectric substrate are cooled from room temperature to a critical temperature of the resonator patterns.