CN-115001437-B - Surface acoustic wave resonator and filter

CN115001437BCN 115001437 BCN115001437 BCN 115001437BCN-115001437-B

Abstract

The invention discloses a surface acoustic wave resonator and a filter. The surface acoustic wave resonator comprises a transducer, wherein the transducer comprises a first bus bar, a second bus bar, a first electrode finger, a first dummy electrode finger, a second electrode finger and a second dummy electrode finger, the first electrode finger and the first dummy electrode finger are alternately arranged and connected to the first bus bar, the second electrode finger and the second dummy electrode finger are alternately arranged and connected to the second bus bar, the first electrode finger and the second dummy electrode finger are oppositely arranged, a first gap is reserved between the first electrode finger and the second dummy electrode finger, the second electrode finger and the first dummy electrode finger are oppositely arranged, a second gap is reserved between the second electrode finger and the first dummy electrode finger, the material density of the first dummy electrode finger and the second dummy electrode finger is the first density, and the material density of the first electrode finger and the second electrode finger is the second density, and the first density is larger than the second density. The technical scheme of the invention realizes the suppression of transverse mode ripple and reduces energy loss.

Inventors

MA YANGYANG
LIU XIAOJUN
Yao Ruoyan
SONG JIAJIA
ZHU DEJIN

Assignees

天通瑞宏科技有限公司

Dates

Publication Date: 20260508
Application Date: 20220614

Claims (9)

1. A surface acoustic wave resonator comprising a transducer; The transducer includes a first bus bar, a second bus bar, a plurality of first electrode fingers, a plurality of first dummy electrode fingers, a plurality of second electrode fingers, and a plurality of second dummy electrode fingers; the first electrode fingers and the first dummy electrode fingers are alternately arranged and connected to the first bus bar; the second electrode fingers and the second dummy electrode fingers are alternately arranged and connected to the second bus bar; The first electrode finger and the second dummy electrode finger are oppositely arranged, a first gap is formed between the first electrode finger and the second dummy electrode finger, the second electrode finger and the first dummy electrode finger are oppositely arranged, and a second gap is formed between the second electrode finger and the first dummy electrode finger; The material density of the first dummy electrode finger and the second dummy electrode finger is a first density, the material density of the first electrode finger and the second electrode finger is a second density, and the first density is greater than the second density; The first bus bar includes a first portion proximate to the first dummy electrode finger and a second portion distal to the first dummy electrode finger, the second portion having a material density less than a material density of the first portion, and/or the second bus bar includes a third portion proximate to the second dummy electrode finger and a fourth portion distal to the second dummy electrode finger, the fourth portion having a material density less than a material density of the third portion; The first dummy electrode fingers are the same material as the first portion, and the second dummy electrode fingers are the same material as the third portion.
2. The surface acoustic wave resonator of claim 1, wherein the first dummy electrode finger and the second dummy electrode finger have a first width and the first electrode finger and the second electrode finger have a second width, and wherein the first width is greater than or equal to the second width.
3. The surface acoustic wave resonator of claim 1, wherein the first electrode finger comprises a first end, a first electrode body, and a second end, the second electrode finger comprises a third end, a second electrode body, and a fourth end, the first end is an end of the first electrode finger opposite the second dummy electrode finger, the third end is an end of the second electrode finger opposite the first dummy electrode finger, the second end is an end of the first electrode finger adjacent the first dummy electrode finger, and the fourth end is an end of the second electrode finger adjacent the second dummy electrode finger; the material density of the first end portion and the third end portion is the first density; the material densities of the first electrode body, the second end portion, the second electrode body, and the fourth end portion are the second densities.
4. The surface acoustic wave resonator of claim 1, wherein the first electrode finger comprises a first end, a first electrode body, and a second end, the second electrode finger comprises a third end, a second electrode body, and a fourth end, the first end is an end of the first electrode finger opposite the second dummy electrode finger, the third end is an end of the second electrode finger opposite the first dummy electrode finger, the second end is an end of the first electrode finger adjacent the first dummy electrode finger, and the fourth end is an end of the second electrode finger adjacent the second dummy electrode finger; the material density of the second end and the fourth end is the first density; the material densities of the first electrode body, the first end portion, the second electrode body, and the third end portion are the second densities.
5. The surface acoustic wave resonator of claim 1, wherein the first electrode finger comprises a first end, a first electrode body, and a second end, the second electrode finger comprises a third end, a second electrode body, and a fourth end, the first end is an end of the first electrode finger opposite the second dummy electrode finger, the third end is an end of the second electrode finger opposite the first dummy electrode finger, the second end is an end of the first electrode finger adjacent the first dummy electrode finger, and the fourth end is an end of the second electrode finger adjacent the second dummy electrode finger; The material densities of the first end, the second end, the third end, and the fourth end are the first densities; The material density of the first electrode body and the second electrode body is the second density.
6. The surface acoustic wave resonator of claim 1, wherein the first electrode finger comprises a first end, a first electrode body, and a second end, the second electrode finger comprises a third end, a second electrode body, and a fourth end, the first end is an end of the first electrode finger opposite the second dummy electrode finger, the third end is an end of the second electrode finger opposite the first dummy electrode finger, the second end is an end of the first electrode finger adjacent the first dummy electrode finger, and the fourth end is an end of the second electrode finger adjacent the second dummy electrode finger; The material density of the part corresponding to the third end part in the first electrode main body is the first density; the material density of the portion of the second electrode body corresponding to the first end portion is the first density.
7. The surface acoustic wave resonator according to any of claims 1-6, characterized in that it further comprises a first reflection grating and a second reflection grating; The first reflecting grating and the second reflecting grating are positioned on two sides of the transducer along the length direction of the first bus bar; The first reflecting grating comprises a third bus bar, a fourth bus bar and a plurality of first reflecting sub-gratings, wherein the first end of the first reflecting sub-grating is connected with the third bus bar, the second end of the first reflecting sub-grating is connected with the fourth bus bar, and the material density of the first part and the second part of the first reflecting sub-grating is the first density, wherein the first part of the first reflecting sub-grating is the part corresponding to the first dummy electrode finger, and the second part of the first reflecting sub-grating is the part corresponding to the first reflecting sub-grating and the second dummy electrode finger; And/or the second reflecting grating comprises a fifth bus bar, a sixth bus bar and a plurality of second reflecting sub-gratings, wherein the first ends of the second reflecting sub-gratings are connected with the fifth bus bar, the second ends of the second reflecting sub-gratings are connected with the sixth bus bar, the material density of the first part and the second part of the second reflecting sub-gratings is the first density, the first part of the second reflecting sub-gratings is the part corresponding to the second reflecting sub-gratings and the first dummy electrode fingers, and the second part of the second reflecting sub-gratings is the part corresponding to the second reflecting sub-gratings and the second dummy electrode fingers.
8. The surface acoustic wave resonator of claim 1, wherein the material of the first dummy electrode finger and the second dummy electrode finger comprises gold or copper and the material of the first electrode finger and the second electrode finger comprises aluminum.
9. A filter comprising the surface acoustic wave resonator of any one of claims 1 to 8.

Description

Surface acoustic wave resonator and filter Technical Field The present invention relates to the field of communications technologies, and in particular, to a surface acoustic wave resonator and a filter. Background With the development of communication technology, the product terminal puts strict requirements on the performance of various devices, and the filter is a key device of a communication system, so that the effect of the acoustic surface filter in the communication system is more and more important. The acoustic surface filter is widely applied to the front end of the radio frequency, has the advantages of low insertion loss, wide bandwidth, small volume and the like, but has various clutter modes, the performance of the acoustic surface filter is seriously affected, and transverse mode ripple is one of the main clutter modes. At present, the transverse mode ripple is mainly restrained by adopting an aperture weighting method, but the aperture weighting needs to increase the size of the resonator, so that the size of the resonator is increased, and the energy loss is larger. Disclosure of Invention The invention provides a surface acoustic wave resonator and a filter, which are used for inhibiting transverse mode ripple and reducing energy loss on the basis of not changing the volume of the resonator. According to an aspect of the present invention, there is provided a surface acoustic wave resonator including a transducer; The transducer includes a first bus bar, a second bus bar, a plurality of first electrode fingers, a plurality of first dummy electrode fingers, a plurality of second electrode fingers, and a plurality of second dummy electrode fingers; The first electrode fingers and the first dummy electrode fingers are alternately arranged and connected to the first bus bar; the second electrode fingers and the second dummy electrode fingers are alternately arranged and connected to the second bus bar; The first electrode finger and the second dummy electrode finger are oppositely arranged, a first gap is formed between the first electrode finger and the second dummy electrode finger, the second electrode finger and the first dummy electrode finger are oppositely arranged, and a second gap is formed between the second electrode finger and the first dummy electrode finger; the material density of the first dummy electrode finger and the second dummy electrode finger is a first density, the material density of the first electrode finger and the second electrode finger is a second density, and the first density is greater than the second density. Optionally, the first dummy electrode finger and the second dummy electrode finger have a first width, and the first electrode finger and the second electrode finger have a second width, and the first width is greater than or equal to the second width. Optionally, the first electrode finger comprises a first end, a first electrode body and a second end, the second electrode finger comprises a third end, a second electrode body and a fourth end, the first end is an end of the first electrode finger opposite to the second dummy electrode finger, the third end is an end of the second electrode finger opposite to the first dummy electrode finger, the second end is an end of the first electrode finger adjacent to the first dummy electrode finger, and the fourth end is an end of the second electrode finger adjacent to the second dummy electrode finger; the material density of the first end portion and the third end portion is the first density; the material densities of the first electrode body, the second end portion, the second electrode body, and the fourth end portion are the second densities. Optionally, the first electrode finger comprises a first end, a first electrode body and a second end, the second electrode finger comprises a third end, a second electrode body and a fourth end, the first end is an end of the first electrode finger opposite to the second dummy electrode finger, the third end is an end of the second electrode finger opposite to the first dummy electrode finger, the second end is an end of the first electrode finger adjacent to the first dummy electrode finger, and the fourth end is an end of the second electrode finger adjacent to the second dummy electrode finger; the material density of the second end and the fourth end is the first density; the material densities of the first electrode body, the first end portion, the second electrode body, and the third end portion are the second densities. Optionally, the first electrode finger comprises a first end, a first electrode body and a second end, the second electrode finger comprises a third end, a second electrode body and a fourth end, the first end is an end of the first electrode finger opposite to the second dummy electrode finger, the third end is an end of the second electrode finger opposite to the first dummy electrode finger, the second end is an end of the first electrode