Curved IDT Resonator Layout for Unwanted Wave Suppression
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Solution Overview
Problem
Existing acoustic wave devices struggle to effectively suppress unwanted waves, leading to increased resonator area or insufficient suppression when trying to reduce unwanted waves.
Innovation Solution
The acoustic wave device incorporates a plurality of acoustic wave resonators, including at least one excitation angle change resonator, where the resonators are connected in series or parallel without additional elements between them, and the excitation angle is not uniform across the IDT electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the number of divided resonators is increased to suppress unwanted waves, then unwanted wave suppression is improved, but the total area of the resonators increases
Solution Approach 1:
The invention changes the excitation angle parameter across the IDT electrode by curving the electrode fingers. This parameter change allows a single resonator to achieve the unwanted wave suppression effect that would otherwise require multiple divided resonators, thereby reducing the total area while maintaining suppression performance.
Solution Approach 2:
The electrode fingers are curved to create different excitation angles across different portions of the IDT electrode. This segmentation of the excitation angle creates multiple acoustic wave paths with different propagation characteristics, achieving suppression of unwanted waves without increasing the physical number of resonators.
2Object-affected harmful factors
If the number of divided resonators is increased to suppress unwanted waves, then unwanted wave suppression is improved, but the device complexity increases
Solution Approach 1:
By changing the excitation angle parameter through curved electrode fingers, the invention achieves unwanted wave suppression within a single resonator structure, avoiding the need to increase the number of resonators and thus reducing device complexity.
Solution Approach 2:
The invention combines multiple excitation angle functions into a single resonator by curving the electrode fingers. This merging allows one resonator to perform the function that would otherwise require multiple separate resonators, simplifying the overall device structure.
3Device complexity
If the excitation angle is made uniform across the IDT electrode, then the resonator structure is simpler, but unwanted waves cannot be sufficiently suppressed
Solution Approach 1:
The electrode fingers are designed with a curved shape rather than a straight configuration, creating asymmetric excitation angles across the IDT electrode. This asymmetry is intentional and functional, enabling unwanted wave suppression while maintaining a relatively simple resonator structure.
Solution Approach 2:
Different portions of the IDT electrode have different local excitation angles due to the curved electrode fingers. This local variation in excitation angle quality allows each portion to contribute differently to acoustic wave generation, achieving unwanted wave suppression without requiring complex external structures.
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 configuration reduces or prevents unwanted waves, allowing for smaller device size without increasing the number of resonators, and improves resonance characteristics by dispersing unwanted waves outside the band.
Implementation Method 1
a piezoelectric substrate including a piezoelectric body layer, and an IDT electrode on the piezoelectric substrate
Implementation Method 2
the excitation angle is not uniform in the IDT electrode... dispersing unwanted waves outside the band
Data Source
AI summary
An acoustic wave device includes acoustic wave resonators each including a piezoelectric substrate including a piezoelectric body layer, and an IDT electrode on the piezoelectric substrate and including electrode fingers. At least one of the acoustic wave resonators is an excitation angle change resonator, in which, the piezoelectric body layer includes a propagation axis and the electrode fingers are curved. In the excitation angle change resonator, an excitation direction of an acoustic wave in a portion of one of the electrode fingers is one of first, second, or third directions. An excitation angle of the excitation angle change resonator is not uniform in the IDT electrode.