SAW Resonator Suppression Layer for Transverse Mode Attenuation
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Solution Overview
Problem
Existing surface acoustic wave resonators suffer from violent fluctuations between passbands due to a strong transverse mode, which adversely affects device performance, and current methods for suppressing this mode, such as apodization and piston structures, are complex and costly.
Innovation Solution
A surface acoustic wave resonator with a piezoelectric substrate and an interdigital transducer, featuring a suppression layer arranged on the substrate or transducer to attenuate the transverse mode, which includes a deceleration layer in recessed portions of the substrate and temperature compensation layers with varying sound velocities to suppress the transverse mode without complex electrode modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If apodization or piston structures are used to suppress transverse mode, then the transverse mode is attenuated, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the physical parameters of the piezoelectric substrate by creating recessed portions with specific depth ranges (0.5-5 μm) and filling them with materials having different acoustic impedances. This parameter modification creates acoustic velocity differences that suppress transverse modes without requiring complex electrode structures like apodization or piston designs.
Solution Approach 2:
The patent replaces the mechanical/electrical complexity of apodization (variable electrode spacing) and piston structures (weighted electrode regions) with a simpler substrate-level solution. By modifying the substrate topology and material composition rather than the electrode configuration, the invention achieves transverse mode suppression through acoustic field control rather than mechanical structure complexity.
2Object-affected harmful factors
If apodization or piston structures are used to suppress transverse mode, then the transverse mode is attenuated, but the manufacturing cost increases
Solution Approach 1:
The patent modifies substrate parameters (recess depth, filling material acoustic impedance) rather than requiring complex electrode fabrication processes. This approach uses standard semiconductor manufacturing techniques for creating recesses and depositing thin films, avoiding the need for specialized apodization or piston structure fabrication equipment and processes.
Solution Approach 2:
The patent extracts the transverse mode suppression function from the electrode structure and relocates it to the substrate level. By removing the need for complex electrode modifications and implementing suppression at the substrate level through recessed portions, the invention simplifies the overall manufacturing process and reduces costs.
3Object-affected harmful factors
If complex electrode modifications are made to suppress transverse mode, then the transverse mode is attenuated, but the device structure becomes more complex
Solution Approach 1:
The patent substitutes complex electrode modifications with a substrate-level acoustic field control mechanism. By using recessed portions filled with materials of different acoustic impedances, the invention controls the acoustic field distribution to suppress transverse modes without altering the electrode structure, thereby maintaining device simplicity.
Solution Approach 2:
The patent introduces an intermediary layer (the recessed portion filling material) between the substrate and the electrode to achieve transverse mode suppression. This intermediary structure with controlled acoustic impedance modifies the acoustic field distribution without requiring direct modification of the electrode, thus maintaining structural simplicity while achieving the desired suppression effect.
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 proposed resonator effectively attenuates the transverse mode with a simpler manufacturing process, reducing complexity and costs while maintaining performance stability.
Implementation Method 1
a suppression layer for suppressing a transverse mode... temperature compensation layers with varying sound velocities to suppress the transverse mode
Implementation Method 2
SAW (surface acoustic wave), i.e. a surface acoustic wave, is an elastic wave that is generated and propagated on a surface of a piezoelectric substrate material
Data Source
AI summary
A surface acoustic wave resonator and a manufacturing method thereof are provided. The surface acoustic wave resonator includes a piezoelectric substrate, an interdigital transducer located on a surface of the piezoelectric substrate, and a suppression layer for suppressing a transverse mode arranged on at least one of the piezoelectric substrate and the interdigital transducer.