IDT Busbar Connection Layout to Preserve Acoustic Wave Q
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Solution Overview
Problem
The existing acoustic wave devices experience degradation of Q characteristics due to the connection between inner and outer busbar portions, which affects their performance.
Innovation Solution
The acoustic wave device incorporates a wide width connecting portion with a larger dimension in the acoustic wave propagation direction to reduce electric resistance between the inner and outer busbar portions, thereby suppressing the degradation of Q characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inner busbar portion and outer busbar portion are connected by multiple fine connecting portions, then the structural connection is achieved, but the Q characteristics degrade due to increased electric resistance
Solution Approach 1:
The patent changes the dimensional parameters of the connecting portions by introducing at least one wide width connecting portion with a larger dimension in the acoustic wave propagation direction. This parameter change reduces electric resistance while maintaining structural connection, thereby improving Q characteristics without sacrificing structural integrity.
2Ease of manufacture
If multiple fine connecting portions are used to connect busbar portions, then the connection structure is formed, but electric resistance increases causing performance degradation
Solution Approach 1:
The patent applies local quality by making specific connecting portions (at least one) have different dimensions than others. The wide width connecting portion has a larger dimension in the acoustic wave propagation direction, creating a localized region with lower electric resistance that reduces overall energy loss while maintaining the multi-portion connection structure for ease of manufacture.
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 implementation of wide width connecting portions effectively reduces electric resistance and minimizes the likelihood of Q characteristic degradation, enhancing the device's performance by confining transverse mode ripples and maintaining higher Q values.
Implementation Method 1
at least one of the plurality of connecting portions is a wide width connecting portion with a dimension in the acoustic wave propagation direction larger than a dimension of each of the remaining connecting portions
Implementation Method 2
an acoustic wave device includes a piezoelectric substrate, and an IDT electrode on the piezoelectric substrate... acoustic velocities in the first low acoustic velocity region and the second low acoustic velocity region are lower than an acoustic velocity in the central region
Data Source
AI summary
An acoustic wave device includes a piezoelectric substrate, and an IDT electrode on the piezoelectric substrate, and the IDT electrode includes an intersection region in which first and second electrode fingers overlap each other in an acoustic wave propagation direction, the intersection region includes a central region and first and second low acoustic velocity regions outside the central region on respective sides in an extending direction of the first and second electrode fingers, first and second busbars include first and second cavities, respectively, first and second inner busbar portions on one side of the first and second cavities, and first and second outer busbar portions on another side are connected by first and second connecting portions, and at least one of the first connecting portions and at least one of the second connecting portions are a first wide width connecting portion and a second wide width connecting portion having a width wider than that of each of remaining first and second connecting portions.