Elastic wave device, filter, and multiplexer

By optimizing the ratio of the temperature coefficient adjustment layer and the mass compensation layer in the interdigital transducer, and combining it with a multilayer substrate structure, the frequency temperature coefficient problem of the elastic wave device was solved, achieving frequency stability and performance improvement.

CN120856092APending Publication Date: 2025-10-28SHOULDER ELECTRONICS CO LTD
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Patent Information

Application Number
CN202510970883.7
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-07-15
Publication Date
2025-10-28

AI Technical Summary

Technical Problem

Existing elastic wave devices have problems with the temperature coefficient of frequency (TCF), which causes frequency drift, affects filter selectivity and insertion loss, and performance degrades especially when temperature changes.

Method used

By optimizing the thickness and density ratio of the temperature coefficient adjustment layer and the mass compensation layer in the interdigital transducer, ensuring that 112/574≤h1ρ1/(h1ρ1+h2ρ2)≤64/109, and combining the material of the piezoelectric layer and the structure of the supporting substrate, a multilayer substrate is formed to adjust the frequency temperature coefficient.

Benefits of technology

It effectively reduces the impact of ambient temperature changes on elastic wave devices, keeps the TCF difference between the resonant frequency and the anti-resonant frequency within a small range, and improves the performance stability of filters and multiplexers.

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Abstract

The invention relates to the technical field of elastic waves, and discloses an elastic wave device, a filter and a multiplexer. The elastic wave device comprises a supporting substrate, a low-sound-velocity layer, a piezoelectric layer and an interdigital transducer, the low-sound-velocity layer is arranged on the supporting substrate, the piezoelectric layer is arranged on the low-sound-velocity layer, the interdigital transducer is arranged on the piezoelectric layer, and the interdigital transducer comprises a temperature coefficient adjusting layer and a mass compensation layer which are sequentially stacked on the piezoelectric layer. According to the elastic wave device, the mass proportion of the temperature coefficient adjusting layer is optimally designed to be within a specific range value, so that the TCF difference value of the resonant frequency and the anti-resonant frequency can be kept at a relatively small level, and the influence of environment temperature change on the elastic wave device is reduced; and the stable performance of a filter and a multiplexer based on the elastic wave device is further maintained.
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