BAW Resonator Reflective Layer Layout for Transverse Wave Blocking
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Solution Overview
Problem
Existing bulk acoustic wave (BAW) resonators face challenges in optimizing the reflection of transverse waves due to asymmetrical structures of the reflective layer, which affects the overall performance and frequency blocking characteristics in high-frequency components.
Innovation Solution
The acoustic resonator features a reflective layer with distinct cross-sectional areas and materials in its first and second sections, positioned between the piezoelectric layer and the second electrode, enhancing the reflection of transverse waves and improving the Q-factor for better frequency blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a symmetrical reflective layer structure is used, then the manufacturing process is simple, but the reflection of transverse waves is not optimized
Solution Approach 1:
The reflective layer is designed with an asymmetrical structure where the first section has a first cross-sectional area and the second section has a second cross-sectional area that is different from the first. This asymmetry optimizes the reflection of transverse waves by creating different acoustic impedance conditions in different regions, thereby improving energy loss characteristics without requiring complex manufacturing processes.
Solution Approach 2:
The reflective layer is divided into multiple sections (first section and second section) with different cross-sectional areas. This segmentation allows each section to contribute differently to the overall acoustic performance, with the first section providing one type of reflection characteristic and the second section providing another, collectively optimizing transverse wave reflection.
2Reliability
If the reflective layer has uniform cross-sectional area, then the structure is simple, but the Q-factor is not optimized
Solution Approach 1:
The reflective layer employs an asymmetrical configuration with the first section having a first cross-sectional area and the second section having a second cross-sectional area different from the first. This asymmetry creates optimized acoustic boundary conditions that enhance the Q-factor by improving the resonance characteristics and reducing energy dissipation, while maintaining a relatively simple overall structure.
3Loss of energy
If the reflective layer is positioned away from the resonant region, then the resonant region design is flexible, but frequency blocking characteristics are reduced
Solution Approach 1:
The reflective layer is segmented into a first section and a second section, where the first section is positioned adjacent to the resonant region and the second section extends outward. This segmentation allows the first section to provide strong frequency blocking characteristics by being close to the resonant region, while the second section can be configured to optimize overall acoustic performance without compromising the blocking 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
This configuration maximizes the reflection of transverse waves and enhances the performance of the acoustic resonator by optimizing the structural design of the reflective layer, leading to improved frequency blocking characteristics.
Implementation Method 1
a bulk acoustic wave (BAW) resonator employing semiconductor thin-film wafer manufacturing technology
Implementation Method 2
a reflective layer disposed along a periphery of the resonant region... enhancing the reflection of transverse waves
Data Source
AI summary
An acoustic resonator includes: a substrate; a resonant region including a first electrode, a piezoelectric layer, and a second electrode disposed on the substrate, and a reflective layer disposed along a periphery of the resonant region; and a connection electrode extending from the second electrode. The reflective layer includes a second section disposed between the resonant region and the connection electrode, and a first section, and a cross-sectional area of the first section is different than a cross-sectional area of the second section.