Tilted Multilayer Interdigital Transducer for Spurious Mode Suppression
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Solution Overview
Problem
Existing acoustic wave filters face challenges in suppressing spurious responses due to strong transverse modes, which affect accuracy and stability, while tilted single-layer interdigital transducer electrodes occupy excessive surface area.
Innovation Solution
Implementing a multilayer interdigital transducer electrode with a non-zero tilt angle and rotation angle, utilizing materials with varying densities and thicknesses to reduce the required surface area while maintaining suppression of spurious responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tilted single-layer interdigital transducer electrode is used to suppress spurious responses, then the suppression of spurious responses is improved, but the surface area occupied increases excessively
Solution Approach 1:
The single-layer electrode is divided into multiple layers (first layer and second layer) with different materials and thicknesses. This segmentation allows the electrode to achieve the necessary mass distribution for spurious response suppression while reducing the overall surface footprint through vertical stacking.
Solution Approach 2:
The design transitions from a two-dimensional single-layer electrode to a three-dimensional multilayer structure. By adding the vertical dimension with multiple layers of varying densities and thicknesses, the electrode achieves effective spurious response suppression without proportionally increasing the horizontal surface area.
2Reliability
If the interdigital transducer electrode has a tilt angle of at least 12 degrees to suppress spurious responses, then the suppression of spurious responses is improved, but the device complexity increases
Solution Approach 1:
The patent specifies a tilt angle of at least 12 degrees as a critical parameter to achieve spurious response suppression. This parameter optimization allows the electrode to maintain acoustic wave generation functionality while effectively suppressing unwanted transverse modes, balancing performance with manageable complexity.
Solution Approach 2:
The electrode uses composite material structure with a first layer (higher density) and a second layer (lower density, greater thickness). This composite approach enables the tilted electrode to achieve the necessary acoustic properties for spurious response suppression while managing the complexity through material selection rather than purely geometric complexity.
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 multilayer interdigital transducer electrode effectively suppresses spurious responses and improves quality factor, reducing the necessary surface area without compromising performance.
Implementation Method 1
A surface acoustic wave resonator can include an interdigital transductor electrode on a piezoelectric substrate. The surface acoustic wave resonator can generate a surface acoustic wave on a surface of the piezoelectric layer
Data Source
AI summary
An acoustic wave device is disclosed. The acoustic wave device can include a multilayer piezoelectric substrate and an interdigital transducer electrode over the multilayer piezoelectric substrate. The interdigital transducer electrode includes a first layer and a second layer over the first layer. The interdigital transducer electrode has a tilt angle of at least 12 degrees. The acoustic wave device being configured to generate a surface acoustic wave having a wavelength L.