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CN-122026849-A - Surface acoustic wave device having different acoustic impedances and electronic apparatus

CN122026849ACN 122026849 ACN122026849 ACN 122026849ACN-122026849-A

Abstract

The invention relates to the technical field of surface acoustic wave devices, in particular to a surface acoustic wave device and electronic equipment with different acoustic impedances, which comprise a piezoelectric substrate, an IDT electrode and a reflecting grating, wherein the IDT electrode and the reflecting grating are arranged on the piezoelectric substrate, the reflecting grating is respectively arranged on two sides of the IDT electrode along a first direction, the reflecting grating comprises a plurality of reflecting electrodes which are arranged at intervals along the first direction, the acoustic impedances of the reflecting electrodes are changed along the first direction, and the reflecting electrodes with different acoustic impedances adopt different manufacturing materials or single manufacturing materials with different material properties. The invention provides a surface acoustic wave device and electronic equipment with different acoustic impedances, which are miniaturized, have obviously weakened unwanted oscillation in passband frequency response, obviously improved quality factors and effectively suppressed transverse parasitic modes.

Inventors

  • WANG YUANYUAN
  • WANG QUAN
  • ZHANG SHUMIN

Assignees

  • 左蓝微(江苏)电子技术有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. A surface acoustic wave device with different acoustic impedances comprises a piezoelectric substrate (100), an IDT electrode (200) and a reflection grating (300), wherein the IDT electrode (200) and the reflection grating (300) are arranged on the piezoelectric substrate (100), the reflection grating (300) is respectively arranged on two sides of the IDT electrode (200) along a first direction, and the reflection grating (300) comprises a plurality of reflection electrodes (320) which are arranged at intervals along the first direction, and the surface acoustic wave device is characterized in that the acoustic impedances of the reflection electrodes (320) are changed along the first direction, and the reflection electrodes (320) with different acoustic impedances are made of different manufacturing materials or single manufacturing materials with different material properties.
  2. 2. The surface acoustic wave device having different acoustic impedances as recited in claim 1, characterized in that the acoustic impedance of the reflection electrode (320) in the reflection grating (300) increases in a direction away from the IDT electrode (200).
  3. 3. The surface acoustic wave device having different acoustic impedances as recited in claim 1, characterized in that the acoustic impedance of the reflection electrode (320) in the reflection grating (300) decreases in a direction away from the IDT electrode (200).
  4. 4. A surface acoustic wave device having different acoustic impedances as set forth in claim 2 or 3, characterized in that the acoustic impedance of the reflection electrode (320) in the reflection grating (300) is gradually changed in a direction away from the IDT electrode (200).
  5. 5. A surface acoustic wave device having different acoustic impedances as set forth in claim 2 or 3, characterized in that the acoustic impedance of the reflection electrode (320) in the reflection grating (300) is stepwise changed in a direction away from the IDT electrode (200).
  6. 6. A surface acoustic wave device having different acoustic impedances as set forth in claim 2 or 3, characterized in that the acoustic impedance of at least one of the reflection electrodes (320) in the reflection grating (300) is graded or/and the acoustic impedance of at least one of the reflection electrodes (320) in the reflection grating (300) is stepwise varied.
  7. 7. A surface acoustic wave device having different acoustic impedances as set forth in claim 2 or 3, characterized in that the acoustic impedance of at least one reflection electrode (320) in said reflection grating (300) is changed gradually and stepwise.
  8. 8. A surface acoustic wave device having different acoustic impedances as set forth in claim 2 or 3, characterized in that the acoustic impedance of each reflecting electrode (320) in the reflecting grating (300) is different.
  9. 9. A surface acoustic wave device having different acoustic impedances as set forth in claim 2 or 3, characterized in that reflection electrodes (320) having the same acoustic impedance are present in the reflection grating (300).
  10. 10. An electronic device comprising a communication circuit and a saw device having different acoustic impedances as claimed in any of claims 1-9 connected to the communication circuit.

Description

Surface acoustic wave device having different acoustic impedances and electronic apparatus Technical Field The invention relates to the technical field of surface acoustic wave devices, in particular to a surface acoustic wave device with different acoustic impedances and electronic equipment. Background The surface acoustic wave device mainly comprises a piezoelectric substrate, an IDT electrode and a reflection grating, wherein the IDT electrode and the reflection grating are arranged on the piezoelectric substrate, and the IDT electrode and the reflection grating convert electric signals into surface acoustic waves of the piezoelectric substrate and are widely applied to mobile communication equipment such as smart phones, tablet computers and the like. With the rapid development of mobile communication technology, higher requirements are put on the performance and the size of surface acoustic wave devices (such as resonators and filters), such as obviously reduced unwanted oscillations in the frequency response, higher quality factor (Q) and more effective lateral parasitic mode suppression, while ensuring miniaturization. Therefore, it is necessary to develop a surface acoustic wave device that is miniaturized, significantly attenuated in unwanted oscillations in the frequency response, significantly improved in quality factor, and effectively suppressed in the lateral parasitic mode. Disclosure of Invention The invention aims to solve the problems in the prior art in the background art and provides a surface acoustic wave device and electronic equipment with different acoustic impedances, wherein the surface acoustic wave device and the electronic equipment are miniaturized, unwanted oscillation in frequency response is obviously weakened, quality factors are obviously improved, and a transverse parasitic mode is effectively restrained. The surface acoustic wave device with different acoustic impedances comprises a piezoelectric substrate, an IDT electrode and a reflection grating, wherein the IDT electrode and the reflection grating are arranged on the piezoelectric substrate, the reflection grating is respectively arranged on two sides of the IDT electrode along a first direction, the reflection grating comprises a plurality of reflection electrodes which are arranged at intervals along the first direction, the acoustic impedances of the reflection electrodes are changed along the first direction, and the reflection electrodes with different acoustic impedances are made of different manufacturing materials or single manufacturing materials with different material properties. Further, the acoustic impedance of the reflection electrode in the reflection grating increases in a direction away from the IDT electrode. Further, the acoustic impedance of the reflection electrode in the reflection grating decreases in a direction away from the IDT electrode. Further, the acoustic impedance of the reflection electrode in the reflection grating is gradually changed in a direction away from the IDT electrode. Further, the acoustic impedance of the reflection electrode in the reflection grating is changed stepwise in a direction away from the IDT electrode. Further, the acoustic impedance of at least one reflecting electrode in the reflecting grating is graded or/and the acoustic impedance of at least one reflecting electrode in the reflecting grating is changed stepwise. Further, at least one reflecting electrode in the reflecting grating has acoustic impedance gradual change and stepwise change. Further, the acoustic impedance of each reflective electrode in the reflective grating is different. Further, reflecting electrodes with the same acoustic impedance are arranged in the reflecting grating. An electronic device includes a communication circuit and the surface acoustic wave device having different acoustic impedances connected to the communication circuit. The invention has the beneficial effects that: (1) According to the invention, the plurality of reflecting electrodes are made of different manufacturing materials or single manufacturing materials with different material properties and have different acoustic impedances, so that acoustic impedances of the plurality of reflecting electrodes are changed along a first direction to form acoustic impedance steps, reflection can be weighted, reflection coefficient (kappa) is controlled, and electrode fingers of the IDT electrodes and reflecting electrodes of the reflecting grids can form soft boundaries, thereby reducing Fresnel ripple, obviously reducing unnecessary oscillation in frequency response and providing a smoother passband. (2) The different acoustic impedances of the reflecting grating in the invention determine the change of the sound velocity under the reflecting grating, create a deeper potential well for the surface wave, force the energy to be kept under the IDT electrode, and obviously improve the quality factor (Q). (3) According to the in