SAW Ladder Filter with Additional Resonator for Thermal Load Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing acoustic wave filters, such as ladder-type filters, face challenges in efficiently filtering signals and managing heat dissipation, leading to potential thermal and electrical load concentration and reduced durability.
Innovation Solution
Incorporating an additional resonator with an IDT electrode connected to the transmission terminal before the transmission filter, positioned outside the passband, which acts as a heat dissipation route and improves the filter's electrical resistance and durability by configuring a heat dissipation path before the initial stage resonator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ladder-type filter is used to filter transmission signals, then the filter characteristics are maintained, but thermal and electrical loads reduce durability and performance
Solution Approach 1:
An additional resonator is introduced as an intermediary component between the transmission terminal and the ladder-type filter. This resonator acts as a mediator to handle thermal and electrical loads, protecting the main filter structure from direct thermal stress while maintaining signal filtering performance
Solution Approach 2:
The filter system is segmented into multiple functional components: the main ladder-type filter for signal filtering and an additional resonator for thermal management. This segmentation allows each component to specialize in its function, with the resonator handling thermal loads and the filter handling signal processing
2Productivity
If the initial stage serial resonator handles thermal load, then filtering is performed, but heat influences filter characteristics and reduces performance
Solution Approach 1:
The additional resonator serves as a thermal intermediary, positioned to receive and dissipate heat before it reaches the initial stage serial resonator. This protects the resonator critical for filtering from thermal degradation while allowing it to maintain its filtering function
Solution Approach 2:
The thermal management function is extracted from the main filter structure and assigned to a separate additional resonator. This separation allows the filter to focus on signal processing while the dedicated resonator handles thermal dissipation
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 additional resonator effectively dissipates heat, reduces thermal and electrical load concentration, and enhances the durability and filter characteristics of the acoustic wave filter, allowing for improved performance and reduced size.
Implementation Method 1
Each acoustic wave resonator for example includes a piezoelectric substrate and an IDT (interdigital transducer) electrode positioned on the piezoelectric substrate
Implementation Method 2
The acoustic wave is for example a surface acoustic wave (SAW)
Data Source
AI summary
A SAW filter includes a substrate including a piezoelectric substrate, a transmission filter, and an additional resonator. The transmission filter is a ladder-type filter filtering signals from a transmission terminal and outputting the result to an antenna terminal. Further, the transmission filter includes one or more serial resonators and one or more parallel resonators which are connected in a ladder configuration on the piezoelectric substrate. An initial stage resonator is the serial resonator. The additional resonator includes an IDT electrode on the piezoelectric substrate. The IDT electrode is connected to the transmission terminal at a stage before the transmission filter and is connected to any of the one or more GND terminals. In the additional resonator, a resonance frequency and an antiresonance frequency are located outside of a passband of the transmission filter.