CN-224233663-U - Surface acoustic wave resonator and surface acoustic wave filter

CN224233663UCN 224233663 UCN224233663 UCN 224233663UCN-224233663-U

Abstract

The utility model belongs to the technical field of resonators and discloses a surface acoustic wave resonator and a surface acoustic wave filter, wherein the surface acoustic wave resonator comprises an interdigital transduction layer, the interdigital transduction layer comprises a first bus bar and a second bus bar, the first bus bar comprises a first interdigital electrode, the second bus bar comprises a second interdigital electrode, a main excitation area is formed in an intersection area of the first interdigital electrode and the second interdigital electrode, the interdigital transduction layer further comprises a third bus bar and a fourth bus bar, the third bus bar comprises a third interdigital electrode, the fourth bus bar comprises a fourth interdigital electrode, a fifth interdigital electrode and a sixth interdigital electrode are respectively arranged on the first interdigital electrode and the second interdigital electrode in an extending mode, a first sub-excitation area is formed in an intersection area of the third interdigital electrode and the fifth interdigital electrode, and a second sub-excitation area is formed in an intersection area of the fourth interdigital electrode and the sixth interdigital electrode. The quality factor value of the surface acoustic wave resonator is improved by arranging the secondary excitation area.

Inventors

BI ZHEN
XIA YONGLU
XU YUQING
GAO PENG
Meng Jiahao
CHU QIANJIN

Assignees

西安砺芯慧感科技有限公司

Dates

Publication Date: 20260512
Application Date: 20250414

Claims (10)

1. A surface acoustic wave resonator, comprising: a piezoelectric substrate; An interdigital transduction layer is arranged above the piezoelectric substrate, the interdigital transduction layer comprises a first bus bar and a second bus bar which are oppositely arranged along a first direction, the first bus bar comprises a first interdigital electrode arranged along the first direction, the second bus bar comprises a second interdigital electrode arranged in parallel with the first interdigital electrode, and an intersection area of the first interdigital electrode and the second interdigital electrode forms a main excitation area; The interdigital transduction layer further comprises a third bus bar and a fourth bus bar which are respectively arranged in an intersecting manner with the first bus bar and the second bus bar, the third bus bar comprises a third interdigital electrode, the fourth bus bar comprises a fourth interdigital electrode which is arranged in parallel with the third interdigital electrode, a fifth interdigital electrode and a sixth interdigital electrode are respectively arranged on the first interdigital electrode and the second interdigital electrode in an extending manner along a first direction, an intersection area of the third interdigital electrode and the fifth interdigital electrode forms a first excitation area, and an intersection area of the fourth interdigital electrode and the sixth interdigital electrode forms a second excitation area.
2. The surface acoustic wave resonator according to claim 1, further comprising a reflective structure comprising a first reflective strip disposed between the first interdigital electrode and the fifth interdigital electrode and a second reflective strip disposed between the second interdigital electrode and the sixth interdigital electrode, wherein the first reflective strip and the second reflective strip are symmetrically disposed along a center line of the first interdigital electrode and the second interdigital electrode in the second direction.
3. The surface acoustic wave resonator according to claim 2, wherein the reflection structure further comprises a third reflection strip and a fourth reflection strip respectively provided on the third interdigital electrode and the fourth interdigital electrode, the third reflection strip is provided at an end far from the first interdigital electrode, the fourth reflection strip is provided at an end far from the second interdigital electrode, and the third reflection strip and the fourth reflection strip are symmetrically provided along a center line of the first interdigital electrode and the second interdigital electrode in the second direction.
4. The surface acoustic wave resonator according to claim 1, wherein the first bus bar and the second bus bar are apodized weighted structures, and each of the first interdigital electrode and the second interdigital electrode is unequal in length.
5. The surface acoustic wave resonator according to claim 4, wherein the lengths of the fingers of the first interdigital electrode and the second interdigital electrode are gradually decreased from the center toward both sides.
6. The surface acoustic wave resonator according to claim 3, wherein the first and second reflective strips have the same width, and the third reflective strip has the same width as the fourth reflective strip.
7. The surface acoustic wave resonator according to claim 2, wherein the reflecting structure is provided on an upper surface of the interdigital transducer layer, or, Grooves are engraved on the upper surface of the piezoelectric substrate, and the reflecting structure is deposited in the grooves of the piezoelectric substrate.
8. The surface acoustic wave resonator of claim 1, further comprising a reflection grating on both sides of the interdigital transducer layer, the reflection grating comprising a plurality of periodically arranged fifth reflection stripes.
9. The surface acoustic wave resonator according to claim 2, characterized in that the thickness of the piezoelectric substrate is 0.3mm-0.7mm, the thickness of the interdigital transduction layer is 50nm-300nm, and the thickness of the reflective structure is 100nm-1000nm.
10. A surface acoustic wave filter comprising the surface acoustic wave resonator according to any of claims 1-9.

Description

Surface acoustic wave resonator and surface acoustic wave filter Technical Field The utility model belongs to the technical field of resonators, and particularly relates to a surface acoustic wave resonator and a surface acoustic wave filter. Background The surface acoustic wave resonator is an electronic element based on the piezoelectric effect, and the basic structure of the surface acoustic wave resonator realizes the efficient conversion of electric signals and surface acoustic waves by preparing periodic interdigital electrodes on the surface of a piezoelectric material. The device has the advantages of high quality factor value, low loss, small volume, easy mass production and the like, and is not only applied to the field of radio frequency communication, but also widely applied to the field of sensors such as temperature sensors, biological sensors, stress sensors and the like. However, when the surface acoustic wave resonator works, the surface acoustic wave excited by the interdigital electrode on the surface of the piezoelectric material can generate not only main wave modes, but also unnecessary transverse modes inevitably, and the transverse modes can generate stray responses, so that the quality factor value of the surface acoustic wave resonator is reduced. Therefore, how to suppress the transverse wave generated during the operation of the surface acoustic wave resonator to improve the quality factor value is a technical problem to be solved. Disclosure of utility model The utility model provides a surface acoustic wave resonator and a surface acoustic wave filter, which are used for solving the technical problem that the conventional surface acoustic wave resonator can generate transverse waves during working. In a first aspect, the present utility model provides a surface acoustic wave resonator comprising: a piezoelectric substrate; An interdigital transduction layer is arranged above the piezoelectric substrate, the interdigital transduction layer comprises a first bus bar and a second bus bar which are oppositely arranged along a first direction, the first bus bar comprises a first interdigital electrode arranged along the first direction, the second bus bar comprises a second interdigital electrode arranged in parallel with the first interdigital electrode, and an intersection area of the first interdigital electrode and the second interdigital electrode forms a main excitation area; The interdigital transduction layer further comprises a third bus bar and a fourth bus bar which are respectively arranged in an intersecting manner with the first bus bar and the second bus bar, the third bus bar comprises a third interdigital electrode, the fourth bus bar comprises a fourth interdigital electrode which is arranged in parallel with the third interdigital electrode, a fifth interdigital electrode and a sixth interdigital electrode are respectively arranged on the first interdigital electrode and the second interdigital electrode in an extending manner along a first direction, an intersection area of the third interdigital electrode and the fifth interdigital electrode forms a first excitation area, and an intersection area of the fourth interdigital electrode and the sixth interdigital electrode forms a second excitation area. Further, the surface acoustic wave resonator further comprises a reflecting structure, wherein the reflecting structure comprises a first reflecting strip arranged between the first interdigital electrode and the fifth interdigital electrode and a second reflecting strip arranged between the second interdigital electrode and the sixth interdigital electrode, and the first reflecting strip and the second reflecting strip are symmetrically arranged along the central lines of the first interdigital electrode and the second interdigital electrode in the second direction. Further, the reflecting structure further comprises a third reflecting strip and a fourth reflecting strip which are respectively arranged on the third interdigital electrode and the fourth interdigital electrode, the third reflecting strip is arranged at one end far away from the first interdigital electrode, the fourth reflecting strip is arranged at one end far away from the second interdigital electrode, and the third reflecting strip and the fourth reflecting strip are symmetrically arranged along the central lines of the first interdigital electrode and the second interdigital electrode in the second direction. Further, the first bus bar and the second bus bar are of apodization weighting structures, and the lengths of the finger bars of the first interdigital electrode and the second interdigital electrode are not equal. Further, the lengths of the finger strips of the first interdigital electrode and the second interdigital electrode are gradually decreased from the center to two sides. Further, the widths of the first reflection strip and the second reflection strip are the same, and the widths