Multilayer Filter Stabilization via Opposing Dielectric Coefficients
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Solution Overview
Problem
Multilayer band-pass filters experience significant changes in pass characteristics due to temperature variations, which can lead to failure in meeting attenuation requirements, especially in narrow passband applications.
Innovation Solution
A multilayer filter device is designed with a stack of dielectric and conductor layers, where the first dielectric layer has a positive temperature coefficient of resonant frequency and the second dielectric layer has a negative temperature coefficient, reducing temperature-induced changes in pass characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a multilayer band-pass filter is miniaturized using a stack of dielectric and conductor layers, then the filter size is reduced, but the pass characteristic shifts with temperature changes
Solution Approach 1:
The patent applies parameter changes by selecting dielectric materials with specific temperature coefficients of resonant frequency. The first dielectric layer uses material with a positive temperature coefficient while the second dielectric layer uses material with a negative temperature coefficient, allowing the filter to compensate for temperature-induced frequency shifts and maintain stable pass characteristics across temperature variations.
Solution Approach 2:
The patent employs composite materials by combining multiple dielectric layers with different temperature coefficients of resonant frequency. This composite structure integrates materials with opposing thermal characteristics (positive and negative coefficients) to create a balanced system that resists temperature-driven frequency drift while maintaining the miniaturized stack configuration.
2Measurement precision
If the passband is narrowed to meet specification requirements, then the selectivity is improved, but the pass characteristic becomes more sensitive to temperature changes
Solution Approach 1:
The patent addresses temperature sensitivity in narrow passband applications by carefully selecting dielectric materials with specific temperature coefficients. The combination of positive and negative temperature coefficient materials allows the filter to maintain its narrow passband selectivity while compensating for temperature effects, preventing the pass characteristic from shifting even when the passband is constricted.
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 stabilizes the pass characteristic of the filter across temperature changes, ensuring consistent performance and meeting attenuation requirements, particularly in narrow passband applications, while also allowing for miniaturization of the filter device.
Implementation Method 1
The first dielectric layer is formed of a first dielectric material having a positive temperature coefficient of resonant frequency. The second dielectric layer is formed of a second dielectric material having a negative temperature coefficient of resonant frequency.
Data Source
AI summary
A filter device includes a filter including at least one inductor and at least one capacitor, and a stack of a plurality of dielectric layers and a plurality of conductor layers. The plurality of dielectric layers include at least one first dielectric layer formed of a first dielectric material and at least one second dielectric layer formed of a second dielectric material. The plurality of conductor layers include at least one first conductor layer in contact with the at least one first dielectric layer, and at least one second conductor layer in contact with the at least one second dielectric layer. The temperature coefficient of resonant frequency of the first dielectric material has a positive value. The temperature coefficient of resonant frequency of the second dielectric material has a negative value.