SAW Resonator Sawtooth Overlap Layout for Spurious Mode Suppression
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Solution Overview
Problem
Traditional surface acoustic wave resonators/filters suffer from clutter in spurious modes, which affects their performance. There is a need to improve the clutter suppression capability of these devices.
Innovation Solution
A surface acoustic wave resonator device is designed with a clutter suppression structure that includes a body structure and a sawtooth structure. The body structure continuously extends along a certain direction and overlaps with the end portions of the interdigital electrodes, while the sawtooth structure is disposed on the side of the body structure away from the body region and overlaps with the interdigital electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional surface acoustic wave resonator is designed without a clutter suppression structure, then the device complexity is reduced and manufacturing is easier, but clutter in spurious modes appears which degrades filter performance
Solution Approach 1:
The clutter suppression structure is segmented into two distinct functional parts: a body structure that continuously extends along the second direction to provide baseline clutter suppression, and a sawtooth structure with multiple protrusions that targets specific spurious modes. This segmentation allows each part to be optimized independently for its specific function while working together to achieve comprehensive clutter suppression.
Solution Approach 2:
The clutter suppression structure is positioned in the third direction (perpendicular to the piezoelectric substrate surface) to overlap with the interdigital electrodes. By utilizing this vertical dimension for overlap rather than only horizontal placement, the structure achieves effective clutter suppression without significantly increasing the horizontal footprint of the device.
2Reliability
If the clutter suppression structure is designed with increased overlapping area with interdigital electrodes, then clutter suppression capability is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The body structure is designed to continuously extend along the second direction and overlap with the interdigital electrodes before the sawtooth structure is added. This preliminary overlapping provides a foundation of clutter suppression that is less sensitive to precise alignment, while the subsequent sawtooth structure adds targeted suppression with moderate precision requirements.
Solution Approach 2:
Different regions of the clutter suppression structure have different overlapping characteristics: the body structure provides continuous overlap along the second direction for broad suppression, while the sawtooth structure provides localized overlap at specific positions to target particular spurious modes. This local differentiation allows each region to contribute optimally without requiring uniform high precision across the entire structure.
3Reliability
If the sawtooth structure extends beyond the interdigital electrode edges into the peripheral region, then clutter suppression is improved, but the device area increases
Solution Approach 1:
The sawtooth structure extends partially beyond the interdigital electrode edges into the peripheral region, providing just enough additional overlap to suppress clutter in those areas without fully occupying the peripheral space. This partial extension achieves the necessary clutter suppression while minimizing the increase in overall device area.
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 increased overlapping area of the clutter suppression structure with the interdigital electrodes enhances the clutter suppression capability, reducing or eliminating clutter in the resonator device and improving its performance. Additionally, the design helps in reducing the size of the resonator device.
Implementation Method 1
a piezoelectric substrate; an interdigital transducer, disposed on a side of the piezoelectric substrate and including a plurality of interdigital electrodes
Data Source
AI summary
A surface acoustic wave resonator device, manufacturing method therefor and filter, the surface acoustic wave resonator device includes: an interdigital transducer, located on a piezoelectric substrate and including first and second interdigital electrode lead-out parts, and first and second interdigital electrodes extending along a first direction and alternately arranged along a second direction, the first interdigital electrode is connected to the first interdigital electrode lead-out part, and the second interdigital electrode is connected to the second interdigital electrode lead-out part; and a clutter suppression structure, including a body structure and a sawtooth structure, wherein the body structure continuously extends along the second direction and overlaps with the interdigital electrodes in a third direction, and the sawtooth structure is disposed at a side of the body structure in the first direction, and at least a portion of the sawtooth structure overlaps with the interdigital electrodes in the third direction.