Acoustic Resonator Scattering Structure for Bulk Mode Suppression
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Solution Overview
Problem
Existing acoustic wave resonators suffer from unwanted parasitic modes that degrade filter performance, necessitating a solution to reduce or eliminate bulk mode acoustic waves.
Innovation Solution
Incorporation of acoustic wave scattering structures within the resonator device, including apodized surfaces, voids, and substrate seams, to disrupt and scatter unwanted coherent waves, allowing for closer integration of multiple filters without performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple filter devices are integrated in close proximity, then device footprint is reduced, but unwanted bulk mode acoustic waves cause interference between devices
Solution Approach 1:
An acoustic wave scattering structure is introduced as an intermediary element between filter devices to scatter bulk mode acoustic waves and prevent interference, enabling close integration without performance degradation
Solution Approach 2:
The harmful bulk mode acoustic waves are extracted and redirected away from the filter devices through the scattering structure, removing the interference problem while maintaining compact integration
2Reliability
If acoustic wave scattering structures are added to suppress bulk mode waves, then filter device performance is improved, but device complexity increases
Solution Approach 1:
The acoustic wave scattering structure utilizes a porous or textured surface configuration that effectively scatters bulk mode waves while maintaining a relatively simple overall device architecture
Solution Approach 2:
The scattering structure introduces surface topology variations in the vertical dimension rather than requiring additional lateral components, reducing overall device complexity while maintaining effectiveness
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 enables a smaller footprint for acoustic resonator devices by effectively reducing unwanted modes, enabling multiple filters to operate efficiently in close proximity.
Implementation Method 1
an acoustic wave scattering structure within the substrate that is distanced away from but sufficiently close to the interdigitated metal so as to scatter the non-lateral component of the acoustic waves
Implementation Method 2
an interdigitated metal disposed over the piezoelectric layer that is configured to generate acoustic waves
Data Source
AI summary
The present disclosure provides an acoustic resonator device, among other things. One example of the disclosed acoustic resonator device includes a substrate having a carrier layer, a first layer disposed over the carrier layer, and a piezoelectric layer disposed over the first layer. The acoustic resonator device is also disclosed to include an interdigitated metal disposed over the piezoelectric layer, where the interdigitated metal is configured to generate acoustic waves within an acoustically active region. The acoustic resonator device is further disclosed to include an acoustic wave scattering structure.