Acoustic Wave Device Spurious Emission Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing acoustic wave resonators with different resonant frequencies face challenges in reducing spurious emissions, as the arrangement of recesses and protrusions on the rough surface is not effectively known for such configurations.
Innovation Solution
The acoustic wave device incorporates a support substrate with a piezoelectric substrate bonded directly or indirectly, featuring protruding and recessed portions between them, with different pitch electrode fingers on each resonator type, optimizing the interval between these features to minimize spurious emissions by configuring series and parallel resonators with distinct pitch intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single interval arrangement of protruding portions and recessed portions is used for all acoustic wave resonators, then the device structure is simple, but spurious emissions cannot be effectively reduced for resonators with different resonant frequencies
Solution Approach 1:
The patent applies local quality by configuring different interval arrangements of protruding portions and recessed portions in different regions corresponding to different acoustic wave resonators. Specifically, a first interval arrangement is used for resonators with a first resonant frequency, and a second interval arrangement is used for resonators with a second resonant frequency. This allows each resonator to have an optimized local structure that minimizes its specific spurious emissions, thereby resolving the contradiction between reducing harmful emissions and maintaining structural simplicity.
2Reliability
If the interval between protruding portions and recessed portions is optimized for one resonant frequency, then spurious emissions are reduced for that frequency, but the optimization does not apply to resonators with different resonant frequencies
Solution Approach 1:
The patent segments the support substrate into multiple regions, each corresponding to a specific acoustic wave resonator type. In each region, the interval between protruding portions and recessed portions is specifically configured to match the resonant frequency of the resonators in that region. This segmentation allows independent optimization of the interval arrangement for each resonator type, ensuring consistent performance across different resonant frequencies while managing the complexity through systematic regional division.
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 effectively reduces spurious emissions by optimizing the interval between protruding and recessed portions, ensuring that each resonator type has an optimal arrangement for minimizing unwanted emissions, enhancing the performance of acoustic wave devices like filters and multiplexers.
Implementation Method 1
a piezoelectric substrate directly or indirectly bonded on the support substrate
Implementation Method 2
Surface acoustic wave resonators are known as acoustic wave resonators used in communication devices
Data Source
AI summary
An acoustic wave device includes: a piezoelectric substrate bonded on a support substrate, a surface including protruding portions and/or recessed portions being interposed between the piezoelectric substrate and the support substrate; a first acoustic wave resonator that includes first electrode fingers with a first average pitch and is disposed on the piezoelectric substrate in a first region where an average interval between the protruding portions and/or the recessed portions in a direction in which the first electrode fingers are arranged is a first interval; and a second acoustic wave resonator that includes second electrode fingers with a second average pitch different from the first average pitch, and is disposed on the piezoelectric substrate in a second region where an average interval between the protruding portions and/or the recessed portions in a direction in which the second electrode fingers are arranged is a second interval different from the first interval.