Coupled Resonator Structure for Spurious Mode Suppression
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Solution Overview
Problem
Acoustic resonators, such as SAW and BAW resonators, face challenges in achieving ideal phase curves due to spurious modes caused by lateral standing waves, which reduce the quality factor and complicate filter designs for high-frequency applications.
Innovation Solution
The use of border rings and apodization techniques to suppress spurious modes, combined with coupled resonator structures that allow for flexible electrical coupling of transducers to optimize impedance behaviors and series resonance frequencies, enhancing filter performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If border rings and apodization techniques are used to suppress spurious modes, then the quality factor is improved, but the device complexity increases
Solution Approach 1:
Border rings and apodization techniques are applied in advance to suppress spurious modes before they can degrade the quality factor. These structures are designed into the resonator from the beginning to prevent the formation of lateral standing waves that would otherwise reduce performance.
Solution Approach 2:
The border ring structure modifies only the peripheral regions of the resonator while leaving the central active area unchanged. This localized modification suppresses spurious modes at the boundaries without affecting the main resonant behavior, thereby improving quality factor with minimal added complexity.
2Adaptability or versatility
If coupled resonator structures are used to optimize impedance behaviors and series resonance frequencies, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The coupled resonator structure serves multiple functions simultaneously: it provides impedance transformation, enables frequency tuning, and maintains signal filtering. By combining these functions into a single integrated structure, the design achieves high adaptability without proportionally increasing complexity.
Solution Approach 2:
The resonator is divided into multiple coupled segments that can be independently designed and optimized. This segmentation allows each section to be tuned for specific impedance or frequency requirements, providing adaptability while maintaining modular simplicity that reduces overall design complexity.
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
These solutions effectively suppress spurious modes, improve the quality factor, and provide flexibility in filter design, leading to better performance in high-frequency applications, particularly in 5G wireless devices.
Implementation Method 1
applying electrical signals across the top electrode 20 and the bottom electrode 22 excites acoustic waves in the piezoelectric layer 18
Implementation Method 2
the bottom transducer is vertically acoustically coupled to the top transducer via the first acoustic coupling structure
Data Source
AI summary
Various arrangements for electrically coupling the electrodes of coupled resonator structures (CRSes) to form unique two- and three-terminal devices as well as the use of such CRSes in filter networks are disclosed.