IDT Electrode Layout for Suppressing Transverse Modes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing acoustic wave devices using piezoelectric layers and interdigital transducers (IDT) electrodes suffer from transverse mode spurious due to uniform acoustic velocity across the crossing region, which affects the efficiency and performance of acoustic wave conversion.
Innovation Solution
The acoustic wave device incorporates a novel planar shape for the IDT electrode, creating multiple regions within the crossing region with varying acoustic velocities, including first to fourth regions with distinct acoustic velocities, reducing transverse mode spurious by alternating electrode finger arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform acoustic velocity is maintained across the crossing region, then the structure is simple, but transverse mode spurious occurs
Solution Approach 1:
The patent applies local quality by creating different acoustic velocity regions (first, second, third, and fourth regions) within the crossing region. Each region has a specific acoustic velocity designed to suppress transverse mode spurious while maintaining overall device functionality. This localized variation in acoustic velocity properties eliminates the harmful transverse modes without requiring complete structural redesign.
Solution Approach 2:
The patent changes the acoustic velocity parameter across different regions of the crossing region. By varying the acoustic velocity from the first region through the fourth region, the patent achieves suppression of transverse mode spurious. This parameter change approach allows control over wave propagation characteristics without fundamentally altering the device structure.
2Object-generated harmful factors
If multiple regions with varying acoustic velocities are created, then transverse mode spurious is reduced, but device complexity increases
Solution Approach 1:
The patent segments the crossing region into multiple distinct regions (first, second, third, and fourth regions), each with its own acoustic velocity characteristics. This segmentation allows targeted control of acoustic wave propagation in different areas, effectively suppressing transverse mode spurious through localized acoustic velocity management.
Solution Approach 2:
The patent introduces asymmetry in the acoustic velocity distribution across the crossing region. Rather than uniform or symmetric velocity profiles, the patent employs an asymmetric arrangement where different regions have different acoustic velocities. This asymmetric configuration is specifically designed to suppress transverse mode spurious that would otherwise occur in symmetric or uniform 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
The solution effectively reduces transverse mode spurious, enhancing the efficiency and performance of acoustic wave conversion by optimizing the acoustic velocity profile across the crossing region.
Implementation Method 1
A known acoustic wave device includes a piezoelectric layer and an interdigital transducer (IDT) electrode positioned on the piezoelectric layer
Implementation Method 2
The region where the multiple electrode fingers of one comb electrode and the multiple electrode fingers of the other comb electrode overlap in the direction in the propagation direction of acoustic waves is called a crossing region
Data Source
AI summary
An acoustic wave device in which multiple second electrode fingers are connected to a different potential from multiple first electrode fingers and arranged in an alternating manner with the multiple first electrode fingers in a propagation direction of acoustic waves. The acoustic wave device includes a crossing region in which the multiple first electrode fingers and the multiple second electrode fingers overlap in the propagation direction of acoustic waves. The crossing region includes first to third regions. The first region is located at tip sides of the multiple first electrode fingers. The second region is located more centrally than the first region in the direction in which the multiple first electrode fingers and the multiple second electrode fingers extend and has a higher acoustic velocity than the first region. The third region is located more centrally than the second region and has a higher acoustic velocity than the second region.