Acoustic Wave Device Metallization Ratio Optimization
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Solution Overview
Problem
Existing acoustic wave devices face challenges in size reduction without compromising performance, leading to deterioration of characteristics such as insertion loss due to the limited size of resonator devices.
Innovation Solution
The acoustic wave device incorporates a substrate with piezoelectricity, featuring a first filter with a higher total average metallization ratio and a second filter with a lower total average metallization ratio, along with resonators of varying lengths and film thicknesses to optimize frequency bands and reduce device size, while maintaining efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the chip size is reduced, then the device size is reduced, but the insertion loss deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the metallization ratios for different frequency bands. The first filter (lower frequency band) uses a first metallization ratio while the second filter (higher frequency band) uses a second metallization ratio that is different from the first. This localized optimization allows each frequency band to have tailored electrical characteristics, enabling size reduction while maintaining insertion loss performance through frequency-specific parameter optimization.
Solution Approach 2:
The patent changes the metallization ratio parameter differently for different frequency bands. By setting the metallization ratio of the first filter to be different from that of the second filter, the patent optimizes the electrical characteristics for each band independently. This parameter differentiation enables the device to achieve compact size while preventing insertion loss deterioration through optimized electromagnetic field distribution in each frequency range.
2Reliability
If the metallization ratio is increased, then the filter performance is improved, but the device size increases
Solution Approach 1:
The patent applies local quality by assigning different metallization ratios to different frequency bands. The first filter operates with a first metallization ratio optimized for its frequency characteristics, while the second filter uses a second metallization ratio suited to its higher frequency band. This localized optimization ensures that each filter achieves its required performance without requiring uniform increases in metallization across the entire device, thereby controlling overall device size.
Solution Approach 2:
The patent optimizes filter performance by changing the metallization ratio parameter specifically for each frequency band. By differentiating the metallization ratios between the first and second filters, the patent achieves optimal electrical characteristics for each band without requiring a uniform increase in metallization that would expand device dimensions. This selective parameter optimization resolves the contradiction between performance and size.
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 allows for a reduction in the size of the acoustic wave device while improving production efficiency and maintaining filter performance by effectively dispersing stresses and reducing insertion loss.
Implementation Method 1
a substrate having piezoelectricity
Implementation Method 2
resonators that include respective interdigital transducer (IDT) electrodes
Data Source
AI summary
An acoustic wave device includes a piezoelectric substrate, a first band pass filter that is on the piezoelectric substrate and has a first pass band, and a second band pass filter that is on the piezoelectric substrate and has a second pass band at a higher frequency than the first pass band. The first and second band pass filters include resonators that include respective IDT electrodes. When a first total average metallization ratio is defined as an average of metallization ratios of all of the IDT electrodes included in the first filter and a second total average metallization ratio is defined as an average of metallization ratios of all of the IDT electrodes included in the second filter, the first total average metallization ratio is greater than the second total average metallization ratio.