Bulk Acoustic Wave Filter Module With Switched Resonators
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Solution Overview
Problem
The increasing demand for small, light filters in mobile communications devices that support multiple frequency bands leads to complex signal processing and increased manufacturing costs and size, particularly due to the need for multiple filters controlling overlapping bands.
Innovation Solution
A filter module incorporating a plurality of bulk acoustic wave resonators with series and shunt resonators, a piezoelectric layer, and switches on a cap, allowing for selective operation of resonators to adjust frequency bands and prevent interference by varying the upper and lower limit frequencies of filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple filters are used to control multiple frequency bands, then the filter can support more communication bands, but the device complexity and size increase
Solution Approach 1:
Multiple filters are integrated into a single filter module with shared components including a common substrate, piezoelectric layers, and capacitor structures. The filters share common electrodes and dielectric layers, merging multiple filtering functions into one compact unit while maintaining the ability to control different frequency bands independently through switching mechanisms.
Solution Approach 2:
The filter module is designed as a universal structure that can control multiple frequency bands simultaneously. Each filter within the module can be independently activated or deactivated through switching elements, allowing the same physical structure to adapt to different communication band requirements without requiring separate dedicated filters for each band.
2Adaptability or versatility
If multiple filters are used to control multiple frequency bands, then the filter can support more communication bands, but the manufacturing cost increases
Solution Approach 1:
Multiple filters are integrated into a single filter module with shared components including a common substrate, piezoelectric layers, and capacitor structures. The filters share common electrodes and dielectric layers, merging multiple filtering functions into one compact unit while maintaining the ability to control different frequency bands independently through switching mechanisms.
Solution Approach 2:
The filtering characteristics are adjusted by changing the switching states of electronic switches rather than by physical manufacturing changes. This allows the same manufactured structure to be configured for different frequency bands through electrical parameter changes, reducing the need for multiple specialized manufacturing processes.
3Adaptability or versatility
If the number of filters is increased, then more frequency bands can be controlled, but the signal processing becomes complicated
Solution Approach 1:
The filter module employs dynamic switching mechanisms that can activate or deactivate specific filters based on the required frequency band. This dynamic control simplifies signal processing by ensuring that only the necessary filters are active at any given time, reducing the computational and processing complexity compared to having all filters continuously operational.
Solution Approach 2:
Specific filtering functions are extracted and isolated into independent filter units within the module, each handling a specific frequency band. This modular extraction allows the signal processing system to engage only the required filtering functions rather than processing through all filters, simplifying the overall signal path.
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 solution enables efficient control of multiple frequency bands with reduced filter module size and manufacturing costs by allowing filters to adjust their frequency bands dynamically, minimizing interference and optimizing space and production efficiency.
Implementation Method 1
a plurality of bulk acoustic wave resonators including one or more series resonators and one or more shunt resonators formed by a first electrode, a piezoelectric layer, and a second electrode sequentially disposed on a substrate
Data Source
AI summary
A filter may include a plurality of bulk acoustic wave resonators including one or more series resonators and one or more shunt resonators formed by a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on a substrate, a cap accommodating the plurality of bulk acoustic wave resonators therein, and one or more switches provided on the cap.