BAW Filter Raised Frame Layout for Q and Frequency Response
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Solution Overview
Problem
Achieving high performance specifications for bulk acoustic wave (BAW) devices is challenging, particularly in terms of quality factor (Q) and frequency response.
Innovation Solution
The use of bulk acoustic wave filters with a first bulk acoustic wave resonator having a multi-layer raised frame structure and a second resonator with a single or dual-layer raised frame structure, where the second resonator has less mass loading and a different frame structure configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform raised frame structure is used for all BAW resonators, then manufacturing is simplified, but performance specifications (quality factor and frequency response) cannot be optimized for different resonators
Solution Approach 1:
The patent applies local quality by configuring different raised frame structures for different resonators based on their specific performance requirements. Series resonators are equipped with raised frame structures having a first configuration, while shunt resonators have raised frame structures with a second configuration. This allows each resonator type to have optimized acoustic properties tailored to its function, improving overall filter performance while maintaining manufacturing feasibility through standardized fabrication processes.
2Reliability
If mass loading is increased in BAW resonators, then frequency response can be adjusted, but quality factor deteriorates
Solution Approach 1:
The patent employs parameter changes by systematically varying the mass loading parameters of raised frame structures across different resonators. The series resonators have raised frame structures with specific mass loading designed to achieve desired frequency responses, while shunt resonators have different mass loading parameters optimized for their function. This controlled variation of mass loading parameters allows independent optimization of frequency response and quality factor for each resonator type, resolving the trade-off between these two critical performance parameters.
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 quality factor (Q) of the BAW devices at various frequency ranges, improving the overall performance of the filters by reducing insertion loss and Gamma loss.
Implementation Method 1
In BAW resonators, acoustic waves propagate in a bulk of a piezoelectric layer
Implementation Method 2
The raised frame structures can reduce energy leakage from a main acoustically active region of the BAW devices
Data Source
AI summary
An acoustic wave filter with different bulk acoustic wave devices is disclosed. The filter includes a first bulk acoustic wave resonator and a second bulk acoustic wave resonator. The first bulk acoustic wave resonator includes a first raised frame structure. The first raised frame structure is a multi-layer raised frame structure. The second bulk acoustic wave resonator includes a second raised frame structure. The first raised frame structure has at least one more raised frame layer than the second raised frame structure.