Surface Acoustic Wave Electrode Layout for Transverse Mode Suppression
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Solution Overview
Problem
Surface acoustic wave devices face issues with unnecessary transverse modes that generate spurious responses and increase insertion loss, making it difficult to suppress these modes due to complex patterns and high failure rates.
Innovation Solution
A surface acoustic wave device with a simpler structure featuring protruding portions on inter-digital electrodes in specific edge regions, which reduces wave velocities in these areas compared to the central region, allowing for effective suppression of transverse modes without the complexity of forming protruding portions on both electrodes in the same edge region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protruding portions are formed on both inter-digital electrodes in the same edge region to suppress transverse mode, then transverse mode suppression is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies asymmetry by forming protruding portions on only one of the first or second inter-digital electrodes in the edge region, rather than symmetrically on both electrodes. This asymmetric configuration is sufficient to suppress transverse modes while reducing manufacturing complexity and the risk of defects compared to forming protrusions on both electrodes.
2Reliability
If complex patterns are used to suppress transverse mode, then transverse mode suppression is improved, but manufacturing reliability decreases
Solution Approach 1:
The patent applies local quality by concentrating the transverse mode suppression function in a localized edge region of the inter-digital electrodes, where protruding portions are formed only in the edge region rather than across the entire electrode structure. This localized approach simplifies the overall pattern fabrication while maintaining effective transverse mode suppression at the critical edge region.
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
This approach effectively suppresses transverse modes, simplifies the structure, and reduces the likelihood of defects, thereby improving the device's performance and reliability.
Implementation Method 1
A surface acoustic wave device converts electrical energy into acoustic wave energy or converts acoustic wave energy into electrical energy
Implementation Method 2
a piezoelectric substrate, first and second bus bars formed on the piezoelectric substrate
Data Source
AI summary
Disclosed is a surface acoustic wave device including a piezoelectric substrate, first and second bus bars formed on the piezoelectric substrate to be opposite each other, a plurality of first inter-digital electrodes that are electrically connected to the first bus bar and extend from the first bus bar toward the second bus bar, and a plurality of second inter-digital electrodes that are electrically connected to the second bus bar and extend from the second bus bar toward the first bus bar, in which the first inter-digital electrodes and the second inter-digital electrodes are alternately arranged.