Bulk Acoustic Wave Resonator Ground Plane for Wider Bandwidth
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Solution Overview
Problem
Existing bulk acoustic wave resonators (BAWRs) face challenges in increasing their bandwidth due to limitations in enhancing the Acousto-electric coupling coefficient, which is proportional to the film characteristics of electrodes and piezoelectric layers.
Innovation Solution
The introduction of a ground plane at a distance from the bulk acoustic wave resonance unit modifies the anti-resonant frequency, generating an additional capacitor component that increases the Acousto-electric coupling coefficient and subsequently the bandwidth of the BAWR, without affecting the resonant frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Acousto-electric coupling coefficient is increased by improving film characteristics of electrodes and piezoelectric layer, then the bandwidth of BAWR is improved, but the manufacturing complexity and difficulty increase
Solution Approach 1:
A ground plane is introduced as an intermediary element between the electrodes and the substrate. This ground plane modifies the anti-resonant frequency by generating an additional capacitor component, thereby increasing the Acousto-electric coupling coefficient and bandwidth without requiring complex film configurations or crystallizability improvements
Solution Approach 2:
The invention changes the electrical parameters of the BAWR system by introducing a ground plane at a specific distance from the bulk acoustic wave resonance unit. This modifies the capacitance characteristics and anti-resonant frequency, thereby increasing the Acousto-electric coupling coefficient and bandwidth through parameter adjustment rather than film structure modification
2Reliability
If ground plane is introduced to increase Acousto-electric coupling coefficient, then bandwidth is improved, but device structure becomes more complex
Solution Approach 1:
The device is segmented into distinct functional layers: the bulk acoustic wave resonance unit, the ground plane, and the substrate. This segmentation allows the ground plane to be positioned at an optimized distance from the resonance unit, enabling independent optimization of the coupling coefficient without redesigning the entire film structure
Solution Approach 2:
The ground plane serves as an intermediary element that simplifies the overall structure compared to complex multi-layer film configurations. By placing the ground plane at a specific distance, the invention achieves enhanced coupling through a simple additive structure rather than complex integrated film designs
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 approach effectively enhances the bandwidth of the BAWR by increasing the Acousto-electric coupling coefficient, improving the filter's frequency selectivity and transmission characteristics.
Implementation Method 1
a piezoelectric layer comprising a first region and a second region, the first region having a first piezoelectric coefficient and the second region having a second piezoelectric coefficient
Implementation Method 2
resonance characteristics
Data Source
Figure 1~3
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Figure 7~9
AI summary
Provided is a bulk acoustic wave resonator (BAWR). The BAWR may include a bulk acoustic wave resonance unit and an anti-resonant frequency modifying unit to modify an anti-resonant frequency generated from the bulk acoustic wave resonance unit.