Acoustic Wave Component With Dielectric Decoupling
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Solution Overview
Problem
Components operating with acoustic waves face limitations in nonlinearities, impedance matching, temperature coefficients of frequency, power compatibility, and coupling of reflection and excitation of acoustic waves, which need to be improved for enhanced performance.
Innovation Solution
A component comprising a piezoelectric substrate, a dielectric, and an electrode finger with a defined overlap region and mechanical finger width, where the dielectric is arranged between the electrode finger and the substrate, allowing for decoupled reflection and excitation of acoustic waves, reduced nonlinearities, and improved impedance matching, power compatibility, and reduced temperature coefficients of frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode finger is completely separated from the piezoelectric substrate by the dielectric, then the static capacitance is reduced and impedance matching is improved, but the mechanical stability and power compatibility are reduced
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the electrode finger and the piezoelectric substrate. This dielectric layer serves as a mediator that provides electrical isolation to reduce static capacitance and improve impedance matching, while still allowing mechanical support to be provided through the structured arrangement of the dielectric and substrate contact regions.
Solution Approach 2:
The dielectric layer is arranged in specific regions between the electrode finger and substrate, creating local variations in the structure. The contact regions provide local mechanical support where needed, while the overlap regions provide electrical isolation, achieving different functional qualities in different spatial locations of the same component.
2Reliability
If the electrical finger width is decreased relative to the mechanical finger width, then nonlinearities are reduced and impedance matching is improved, but the coupling of reflection and excitation of acoustic waves is reduced
Solution Approach 1:
The electrode finger structure is segmented into distinct functional regions: contact regions where the electrode touches the substrate for mechanical support and acoustic wave generation, and overlap regions where the electrode overlaps the dielectric for electrical isolation and capacitance control. This segmentation allows independent optimization of electrical and mechanical properties.
Solution Approach 2:
Different regions of the electrode finger structure are given different functional qualities: the contact regions are optimized for mechanical coupling and acoustic wave generation, while the overlap regions are optimized for electrical isolation and capacitance reduction. This local differentiation resolves the contradiction between coupling strength and nonlinearity reduction.
3Reliability
If the dielectric is arranged between the electrode finger and the substrate, then the static capacitance is reduced and impedance matching is improved, but the device complexity increases
Solution Approach 1:
The dielectric layer serves as an intermediary element that, while adding a structural component, provides significant functional benefits in capacitance reduction and impedance matching. The addition of this single intermediate layer is a relatively simple structural modification that achieves multiple performance improvements simultaneously.
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 enhances the flexibility in design, reduces static capacitance fluctuations, improves impedance matching, and stabilizes power compatibility, while maintaining unchanged pole zero distance, allowing for efficient and stable operation of acoustic wave components.
Implementation Method 1
Components operating with acoustic waves can convert electrical signals into acoustic waves, and vice versa, on account of the piezoelectric effect
Implementation Method 2
The static capacitance of the electrode fingers is reduced by the at least partial arrangement of a dielectric between at least one electrode finger and the piezoelectric substrate
Data Source
AI summary
The invention concerns a component (B) operating with acoustic waves, in which the reflection and excitation are largely decoupled. For this purpose, a component comprises a dielectric (DL) which is arranged between an electrode finger (EF) and a piezoelectric substrate (PSU) and at least partially overlaps the electrode finger.