Acoustic Wave Reflector Layout for Lower Return Loss
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Solution Overview
Problem
Existing acoustic wave devices face challenges in preventing an increase in return loss, which affects their performance in applications such as mobile phone filters.
Innovation Solution
The acoustic wave device incorporates a piezoelectric substrate with interdigitated electrode fingers and reflectors, featuring connection electrode formation regions with varying metallization ratios to control the distribution of metal coverage, thereby reducing acoustic wave leakage and preventing return loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional IDT electrode configuration is used with uniform metallization, then the device structure is simple, but return loss increases and acoustic wave leakage occurs
Solution Approach 1:
The patent applies local quality by varying the metallization ratio in different regions of the reflector busbars. Specifically, the connection electrode formation regions have a first metallization ratio while other regions have a second metallization ratio, creating localized differences in metal coverage that control acoustic wave reflection and prevent return loss without requiring complete structural redesign
Solution Approach 2:
The patent changes the metallization ratio parameter in the connection electrode formation regions of the reflector busbars. By adjusting the metal coverage ratio in these specific regions, the acoustic wave reflection characteristics are optimized to prevent return loss while maintaining overall device performance
2Loss of energy
If the acoustic wave device uses uniform metal coverage in reflectors, then manufacturing is easier, but acoustic wave leakage increases
Solution Approach 1:
The patent implements local quality by providing different metallization ratios in specific regions of the reflector busbars. The connection electrode formation regions have enhanced metal coverage compared to other regions, creating localized acoustic wave confinement that prevents leakage without requiring complete restructuring of the manufacturing process
Solution Approach 2:
The patent segments the reflector busbar into distinct regions with different metallization characteristics. The connection electrode formation regions are separated from other regions, each with optimized metal coverage ratios, allowing independent optimization of acoustic wave reflection and manufacturing considerations
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 effectively minimizes return loss and enhances the Q value, ensuring improved performance and reduced insertion loss in filter devices.
Implementation Method 1
an acoustic wave device includes a piezoelectric substrate, an IDT electrode on the piezoelectric substrate
Implementation Method 2
an IDT electrode on the piezoelectric substrate and including a first busbar and a second busbar facing each other, and a plurality of first electrode fingers and a plurality of second electrode fingers interdigitated with each other
Implementation Method 3
a pair of reflectors on the piezoelectric substrate and facing each other across the IDT electrode in a second direction
Data Source
AI summary
An acoustic wave device includes a piezoelectric substrate, an IDT electrode on the piezoelectric substrate and including first and second busbars including first and second interdigitated electrode fingers, and reflectors on the piezoelectric substrate facing each other across the IDT electrode. In the IDT electrode, a pair of regions outward of first and second base ends of the first and second electrode fingers are a pair of outer regions, and regions extending from the pair of outer regions are a pair of extended outer regions. Each of the reflectors includes a pair of reflector busbars facing each other and reflector electrode fingers electrically connected to the pair of reflector busbars. Each of the reflector busbars includes a plurality of reflector connection electrodes in a portion of the reflector located in one of the extended outer regions and directly or indirectly connected to the reflector electrode fingers.