CN115425941A

CN115425941A - Resonator, filter and electronic device

Info

Publication number: CN115425941A
Application number: CN202210912555.8A
Authority: CN
Inventors: 李天年; 杜波; 王华磊; 倪建兴
Original assignee: Ruishi Chuangxin Chongqing Technology Co ltd
Current assignee: Ruishi Chuangxin Chongqing Technology Co ltd
Priority date: 2022-07-30
Filing date: 2022-07-30
Publication date: 2022-12-02

Abstract

The application provides a resonator, a filter and electronic equipment, the resonator includes piezoelectric substrate, interdigital transducer and reflection configuration, and interdigital transducer includes first busbar, second busbar, a plurality of first electrode finger and a plurality of second electrode finger. The first electrode fingers are connected to the first bus bar and extend toward the second bus bar, and the second electrode fingers are connected to the second bus bar and extend toward the first bus bar. The interdigital transducer further includes at least one piston structure located on at least a portion of the first electrode finger, at least one of the piston structures located on the first electrode finger including two metal layers having different thicknesses, and at least one of the piston structures located on the second electrode finger including two metal layers having different thicknesses. Acoustic reflection is formed by changing the transmission speed of the acoustic wave signals on the piezoelectric substrate in the region where the two metal layers are located, so that the leakage of the acoustic wave signals is avoided, and the transverse mode of the resonator is further suppressed.

Description

Resonator, filter and electronic device

Technical Field

The present application relates to the field of communications technologies, and in particular, to a resonator, a filter having the resonator, and an electronic device having the filter.

Background

The surface acoustic wave device processes an acoustic signal propagating on the surface of a piezoelectric substrate using the characteristics of an acousto-electric transducer. The surface acoustic wave device has the advantages of low cost, small volume, multiple functions and the like, so that the surface acoustic wave device is widely applied to the fields of radar, communication, navigation, identification and the like. The surface acoustic wave device mainly comprises a plurality of Interdigital transducers (IDTs) on a piezoelectric substrate, wherein the IDTs can convert an electric signal into an acoustic signal or convert the acoustic signal into the electric signal. The interdigital transducer comprises two parallel bus bars and a plurality of electrode fingers vertically connected to the bus bars.

The high order Transverse Mode (Transverse Mode) of the SAW causes acoustic leakage, resulting in acoustic energy loss and reduced Q factor. To suppress the transverse mode of the surface acoustic wave device, it is common to add dummy fingers to the bus bars or pistons (piston) at the ends of the electrode fingers to change the acoustic velocity distribution of the surface acoustic wave. However, the excitation of transverse modes cannot be completely suppressed by adding a piston by adding the end of a dummy finger or an electrode finger.

Therefore, how to solve the problem of further suppressing excitation of transverse modes to avoid surface acoustic wave leakage is an urgent need to be solved by those skilled in the art.

Disclosure of Invention

In view of the above-mentioned deficiencies of the prior art, it is an object of the present application to provide a resonator, a filter having the resonator, and an electronic device having the filter, which aim to solve the problem of the prior art that the quality factor value of a surface acoustic wave filter is reduced due to surface acoustic wave leakage.

In order to solve the above technical problem, an embodiment of the present application provides a resonator, including the piezoelectric substrate, be located interdigital transducer on the piezoelectric substrate and set up in the reflection configuration of interdigital transducer's relative both sides, interdigital transducer includes:

the first bus bar and the second bus bar are oppositely arranged;

a plurality of first electrode fingers connected to the first bus bar and extending toward the second bus bar, and a plurality of second electrode fingers connected to the second bus bar and extending toward the first bus bar, the plurality of first electrode fingers and the plurality of second electrode fingers being alternately arranged in sequence;

at least one piston structure disposed on at least a portion of the first electrode fingers, the piston structure being located at least at an end of the first electrode fingers facing away from the first bus bar, at least one piston structure disposed on at least a portion of the second electrode fingers, the piston structure being located at least at an end of the second electrode fingers facing away from the second bus bar;

at least one of the piston structures on the first electrode finger includes two metal layers having different thicknesses, and at least one of the piston structures on the second electrode finger includes two metal layers having different thicknesses.

In summary, the resonator that this application embodiment provided includes the piezoelectric substrate and is located interdigital transducer on the piezoelectric substrate, interdigital transducer includes first busbar, second busbar, a plurality of first electrode finger and a plurality of second electrode finger. The first electrode fingers are connected to the first bus bar and extend toward the second bus bar, and the second electrode fingers are connected to the second bus bar and extend toward the first bus bar. The interdigital transducer further comprises at least one piston structure arranged on the first electrode finger and at least one piston structure arranged on the second electrode finger, at least one of the piston structures positioned on the first electrode finger comprises two metal layers with different thicknesses, and at least one of the piston structures positioned on the second electrode finger comprises two metal layers with different thicknesses. Therefore, the resonator of the application can change the transmission speed of the sound wave signals on the piezoelectric substrate in the area where the two metal layers are located by arranging the metal layers with different thicknesses on at least part of the electrode fingers to form acoustic reflection, so that the leakage of the sound wave signals is avoided, the sound wave signals are limited in the interdigital transducer, and the suppression of the transverse mode of the resonator is further improved.

In an exemplary embodiment, at least one of the piston structures on the first electrode finger comprises two metal layers of adjacent and different thicknesses, and at least one of the piston structures on the second electrode finger comprises two metal layers of adjacent and different thicknesses. Or at least one of the piston structures located on the first electrode finger comprises two metal layers with a preset distance and different thicknesses, and at least one of the piston structures located on the second electrode finger comprises two metal layers with a preset distance and different thicknesses.

In an exemplary embodiment, the first electrode fingers and the second electrode fingers are alternately arranged in sequence along the extending direction of the first bus bar and the second bus bar to form an alternate region, and the alternate region includes a first edge region, a second edge region, a middle region, a third edge region and a fourth edge region, which are sequentially arranged in a direction from the first bus bar to the second bus bar.

In an exemplary embodiment, the at least one piston structure disposed on at least a portion of the first electrode fingers and at least a portion of the second electrode fingers each includes a first piston structure and a second piston structure disposed at an interval, the first piston structure includes a first metal layer and a second metal layer, and the second piston structure includes a third metal layer and a fourth metal layer. The thickness of the first metal layer is different from that of the second metal layer, and the thickness of the third metal layer is different from that of the fourth metal layer; the third metal layer, the fourth metal layer, the first metal layer and the second metal layer are sequentially located in the first edge area, the second edge area, the third edge area and the fourth edge area along the extending direction of the first electrode finger, and the second metal layer is located at the end portion of the first electrode finger, which faces away from the first bus bar. The third metal layer, the fourth metal layer, the first metal layer and the second metal layer are sequentially located in the fourth edge area, the third edge area, the second edge area and the first edge area along the extending direction of the second electrode finger, and the second metal layer is located at the end portion of the second electrode finger, which faces away from the second bus bar.

In an exemplary embodiment, the at least one piston structure disposed on at least a portion of the first electrode fingers and at least a portion of the second electrode fingers each include a first piston structure and a second piston structure disposed at intervals, the first piston structure includes a first metal layer, the second piston structure includes a third metal layer and a fourth metal layer, and the third metal layer and the fourth metal layer have different thicknesses. The third metal layer, the fourth metal layer and the first metal layer are sequentially located in the first edge area, the second edge area and the third edge area along the extending direction of the first electrode finger; the third metal layer, the fourth metal layer and the first metal layer are sequentially located in the fourth edge area, the third edge area and the second edge area along the extending direction of the second electrode finger.

In an exemplary embodiment, the at least one piston structure disposed on at least a portion of the first electrode fingers and at least a portion of the second electrode fingers each include a first piston structure and a second piston structure disposed at intervals, the first piston structure includes a second metal layer, the second piston structure includes a third metal layer and a fourth metal layer, wherein the third metal layer and the fourth metal layer have different thicknesses. The third metal layer, the fourth metal layer and the second metal layer are sequentially located in the first edge area, the second edge area and the fourth edge area along the extending direction of the first electrode finger, and the second metal layer is located at an end portion of the first electrode finger, which faces away from the first bus bar. The third metal layer, the fourth metal layer and the second metal layer are sequentially located in the fourth edge area, the third edge area and the first edge area along the extending direction of the second electrode finger, and the second metal layer is located at the end portion of the second electrode finger, which faces away from the second bus bar.

In an exemplary embodiment, the at least one piston structure disposed on at least a portion of the first electrode fingers and at least a portion of the second electrode fingers each includes a first piston structure including a first metal layer and a second metal layer, wherein a thickness of the first metal layer is different from a thickness of the second metal layer. The first metal layer and the second metal layer are sequentially located in the third edge region and the fourth edge region along the extending direction of the first electrode finger, and the second metal layer is located at the end portion of the first electrode finger back to the first bus bar. The first metal layer and the second metal layer are sequentially located in the second edge area and the first edge area along the extending direction of the second electrode finger, and the second metal layer is located at an end portion of the second electrode finger, which faces away from the second bus bar.

In an exemplary embodiment, a thickness of the metal layer at the first edge region is greater than a thickness of the metal layer at the second edge region, and a thickness of the metal layer at the fourth edge region is greater than a thickness of the metal layer at the third edge region.

In an exemplary embodiment, a ratio of a length of the metal layer located at the first edge region to a length of the metal layer located at the second edge region is 0.8 to 1.2, and a ratio of a length of the metal layer located at the fourth edge region to a length of the metal layer located at the third edge region is 0.8 to 1.2.

In an exemplary embodiment, a ratio of a width of the metal layer at the first edge region to a width of the metal layer at the second edge region is 0.8 to 1.2, and a ratio of a width of the metal layer at the fourth edge region to a width of the metal layer at the third edge region is 0.8 to 1.2.

In an exemplary embodiment, a ratio of a thickness of the metal layer located at the first edge region to a thickness of the metal layer located at the second edge region is 1.2 to 5, and a ratio of a thickness of the metal layer located at the fourth edge region to a thickness of the metal layer located at the third edge region is 1.2 to 5.

In an exemplary embodiment, a ratio of a length of the metal layer located at the first edge region to a length of the metal layer located at the second edge region is 1, and a ratio of a length of the metal layer located at the fourth edge region to a length of the metal layer located at the third edge region is 1. The ratio of the width of the metal layer located in the first edge region to the width of the metal layer located in the second edge region is 1, and the ratio of the width of the metal layer located in the fourth edge region to the width of the metal layer located in the third edge region is 1. The ratio of the thickness of the metal layer located in the first edge region to the thickness of the metal layer located in the second edge region is 2, and the ratio of the thickness of the metal layer located in the fourth edge region to the thickness of the metal layer located in the third edge region is 2.

In an exemplary embodiment, the sound velocity corresponding to the middle region is greater than the sound velocity corresponding to the first edge region and the sound velocity corresponding to the second edge region, and the sound velocity corresponding to the first edge region is different from the sound velocity corresponding to the second edge region. The sound velocity corresponding to the middle region is greater than the sound velocity corresponding to the third edge region and the sound velocity corresponding to the fourth edge region, and the sound velocity corresponding to the third edge region is different from the sound velocity corresponding to the fourth edge region.

In an exemplary embodiment, the sound velocity corresponding to the second edge region is greater than the sound velocity corresponding to the first edge region, and the sound velocity corresponding to the third edge region is greater than the sound velocity corresponding to the fourth edge region.

In an exemplary embodiment, a width of the metal layer on the first electrode finger is less than or equal to a width of the first electrode finger, and a width of the metal layer on the second electrode finger is less than or equal to a width of the second electrode finger.

In an exemplary embodiment, a thickness of the metal layer on the first electrode finger is less than a thickness of the first electrode finger, and a thickness of the metal layer on the second electrode finger is less than a thickness of the second electrode finger.

In an exemplary embodiment, the interdigital transducer further includes a plurality of first dummy fingers and a plurality of second dummy fingers, the first dummy fingers are disposed between the first electrode fingers and the second bus bar, and the first dummy fingers are connected to the second bus bar; the second dummy finger is disposed between the second electrode finger and the first bus bar, and the second dummy finger is connected to the first bus bar.

In an exemplary embodiment, the resonator further comprises a temperature compensation layer covering the interdigital transducer on the piezoelectric substrate.

Based on the same inventive concept, the embodiments of the present application further provide a resonator, which includes a piezoelectric substrate and an interdigital transducer located on the piezoelectric substrate, where the interdigital transducer includes:

the first bus bar and the second bus bar are oppositely arranged;

the first electrode fingers and the second electrode fingers are sequentially and alternately arranged along the extending direction of the first bus bar and the second bus bar to form an alternate region, and the alternate region comprises at least two fifth edge regions, a middle region and at least two sixth edge regions which are sequentially arranged in the direction from the first bus bar to the second bus bar;

the sound velocities corresponding to the middle region are respectively greater than the sound velocities corresponding to the at least two fifth edge regions and the sound velocities corresponding to the at least two sixth edge regions;

sound velocities corresponding to the at least two fifth edge regions sequentially arranged from the middle region to the direction of the first bus bar are sequentially reduced;

the sound velocities corresponding to the at least two sixth edge regions arranged in sequence from the middle region to the direction of the second bus bar are reduced in sequence.

To sum up, the resonator that this application embodiment provided includes the piezoelectric substrate and is located interdigital transducer on the piezoelectric substrate, interdigital transducer includes first busbar, second busbar, a plurality of first electrode finger and a plurality of second electrode finger. The first electrode fingers are connected with the first bus bar and extend toward the second bus bar and the second electrode fingers are connected with the second bus bar and extend toward the first bus bar. The first electrode fingers and the second electrode fingers are sequentially and alternately arranged to form an alternating region, and the alternating region comprises at least two fifth edge regions, a middle region and at least two sixth edge regions which are sequentially arranged in a direction from the first bus bar to the second bus bar. The sound velocity corresponding to the middle region is respectively greater than the sound velocities corresponding to the at least two fifth edge regions and the sound velocities corresponding to the at least two sixth edge regions, so that acoustic reflection is formed on the piezoelectric substrate, leakage of acoustic wave signals is avoided, the acoustic wave signals are limited in the interdigital transducer, and suppression of transverse modes of the resonator is improved.

Based on the same inventive concept, the embodiment of the present application further provides a filter, which at least comprises a plurality of resonators as described above.

In summary, the filter includes a plurality of resonators, each resonator includes a piezoelectric substrate and an interdigital transducer located on the piezoelectric substrate, and each interdigital transducer includes a first bus bar, a second bus bar, a plurality of first electrode fingers, and a plurality of second electrode fingers. The first electrode fingers are connected to the first bus bar and extend toward the second bus bar, and the second electrode fingers are connected to the second bus bar and extend toward the first bus bar. The interdigital transducer further comprises at least one piston structure arranged on the first electrode finger and at least one piston structure arranged on the second electrode finger, wherein at least one of the piston structures on the first electrode finger comprises two metal layers with different thicknesses, and at least one of the piston structures on the second electrode finger comprises two metal layers with different thicknesses. Therefore, the transmission speed of the sound wave signals on the piezoelectric substrate in the area where the two metal layers are located is changed, acoustic reflection is formed, the sound wave signals are limited in the interdigital transducer, the sound wave signals are prevented from leaking, and the inhibition of the transverse mode of the resonator is further improved.

Based on the same inventive concept, the embodiment of the present application further provides an electronic device, which includes a substrate and the above-mentioned filter, where the filter is mounted on the substrate and electrically connected to the substrate.

To sum up, the electronic equipment that this application embodiment provided includes base plate and wave filter, the wave filter includes a plurality of syntonizers, the syntonizer includes the piezoelectric substrate and is located interdigital transducer on the piezoelectric substrate, interdigital transducer includes first busbar, second busbar, a plurality of first electrode finger and a plurality of second electrode finger. The first electrode fingers are connected to the first bus bar and extend toward the second bus bar, and the second electrode fingers are connected to the second bus bar and extend toward the first bus bar. The interdigital transducer further comprises at least one piston structure arranged on the first electrode finger and at least one piston structure arranged on the second electrode finger, wherein at least one of the piston structures on the first electrode finger comprises two metal layers with different thicknesses, and at least one of the piston structures on the second electrode finger comprises two metal layers with different thicknesses. Therefore, the resonator of the application can change the transmission speed of the sound wave signals on the piezoelectric substrate in the area where the two metal layers are located by arranging the metal layers with different thicknesses on at least part of the electrode fingers to form acoustic reflection, so that the leakage of the sound wave signals is avoided, the sound wave signals are limited in the interdigital transducer, and the suppression of the transverse mode of the resonator is further improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic layer structure diagram of a first resonator disclosed in an embodiment of the present application;

FIG. 2 is a schematic diagram of a front view of an interdigital transducer of the resonator shown in FIG. 1;

fig. 3 is a schematic diagram of a layer structure of a second resonator disclosed in the embodiment of the present application;

FIG. 4 is a schematic diagram of a front view of an interdigital transducer of the resonator shown in FIG. 3;

FIG. 5 is a schematic diagram of a layer structure of a third resonator according to an embodiment of the disclosure;

FIG. 6 is a schematic diagram of a front view of an interdigital transducer of the resonator shown in FIG. 5;

fig. 7 is a schematic diagram of a layer structure of a fourth resonator disclosed in the embodiment of the present application;

FIG. 8 is a schematic front view of an interdigital transducer of the resonator shown in FIG. 7;

FIG. 9 is a schematic diagram of an admittance curve corresponding to a first preferred structural parameter of an interdigital transducer disclosed in an embodiment of the present application;

FIG. 10 is a schematic diagram of an admittance curve corresponding to a second preferred structural parameter of an interdigital transducer disclosed in an embodiment of the present application;

FIG. 11 is a schematic diagram of an admittance curve corresponding to a third preferred structural parameter of an interdigital transducer disclosed in an embodiment of the present application;

FIG. 12 is a graph illustrating admittance curves corresponding to structural parameters of a prior art interdigital transducer;

fig. 13 is a schematic diagram of sound velocity distribution corresponding to each region in the resonator shown in fig. 1;

fig. 14 is a schematic diagram of sound velocity distribution corresponding to each region in the resonator shown in fig. 3;

fig. 15 is a schematic diagram of sound velocity distribution corresponding to each region in the resonator shown in fig. 5;

fig. 16 is a schematic diagram of sound velocity distribution corresponding to each region in the resonator shown in fig. 7;

FIG. 17 is a schematic diagram of a fifth layer structure of a resonator according to an embodiment of the disclosure;

FIG. 18 is a schematic diagram of a front view of an interdigital transducer of the resonator shown in FIG. 17;

fig. 19 is a schematic structural diagram of a sixth resonator disclosed in an embodiment of the present application;

fig. 20 is a schematic structural diagram of a filter disclosed in an embodiment of the present application.

Description of the reference numerals:

q1 — first edge region; q2 — second edge region; c-middle region; q3 — third edge region; q4-fourth edge region; a 1-interdigital transducer; 7-a piezoelectric substrate; 8-a substrate; 9-temperature compensation layer; 10-a first busbar; 20-a second bus bar; 40-first electrode fingers; 50-second electrode fingers; 60-piston configuration; 80-a first piston structure; 81-a first metal layer; 82-a second metal layer; 90-a second piston structure; 91-a third metal layer; 92-a fourth metal layer; 101-a resonator; 102-a resonator; 103-a resonator; 104-a resonator; 105-a resonator; 106-resonator; 130-first artificial finger; 140-second artificial finger; 200-a filter; IN-input terminal; an OUT-output terminal; bl-series branch; b2-parallel branch; GND-ground connection.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

The following description of the various embodiments refers to the accompanying drawings, which are included to illustrate specific embodiments that can be implemented by the application. The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings). Directional phrases used in this application, such as, for example, "upper," "lower," "front," "rear," "left," "right," "inner," "outer," "side," and the like, refer only to the orientation of the appended drawings and are, therefore, used herein for better and clearer illustration and understanding of the application and are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the application.

In the description of the present application, it should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; may be a mechanical connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art. It should be noted that the terms "first", "second", and the like in the description and claims of the present application and in the drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "comprises," "comprising," "includes," "including," or "including," when used in this application, specify the presence of stated features, operations, elements, and/or the like, but do not limit one or more other features, operations, elements, and/or the like. Furthermore, the terms "comprises" or "comprising" indicate the presence of the respective features, numbers, steps, operations, elements, components or combinations thereof disclosed in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components or combinations thereof, and are intended to cover non-exclusive inclusions. It is also to be understood that the term "at least one" as used herein means one and more than one, such as one, two or three, etc., and the term "plurality" means at least two, such as two or three, etc., unless specifically limited otherwise.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Referring to fig. 1, fig. 1 is a schematic layer structure diagram of a first resonator according to an embodiment of the present disclosure. As shown in fig. 1, a resonator 101 provided in the embodiment of the present application may include at least a piezoelectric substrate 7, a plurality of interdigital transducers 1 located on one side of the piezoelectric substrate 7, and reflection structures disposed on two opposite sides of the interdigital transducers 1.

Specifically, when the interdigital transducer 1 receives an alternating electric signal and generates an alternating electric field corresponding to the alternating electric signal, the piezoelectric substrate 7 deforms under the action of the alternating electric field. Since the electric field intensity of the alternating electric field is varied, the degree of deformation of the piezoelectric substrate 7 is varied with time, and thus an acoustic wave signal is generated on the surface of the piezoelectric substrate 7 and propagates on the surface of the piezoelectric substrate 7. The phenomenon that the piezoelectric substrate 7 deforms under the action of the alternating electric field is called inverse piezoelectric Effect (change piezoelectric Effect).

The acoustic wave signal propagates on the piezoelectric substrate 7 to the other interdigital transducer 1. The acoustic signal deforms the piezoelectric substrate 7 in this region, and the piezoelectric substrate 7 generates equal positive and negative charges on its opposite surfaces in order to form an electrical signal on the interdigital transducer 1 in order to resist deformation. The phenomenon that the Piezoelectric substrate 7 deformed generates Positive and negative charges is called Positive Piezoelectric Effect (Positive Piezoelectric Effect).

Referring to fig. 2, fig. 2 is a schematic front view of an interdigital transducer of the resonator shown in fig. 1. In the present embodiment, each of the interdigital transducers 1 includes a first bus bar 10, a second bus bar 20, a plurality of first electrode fingers 40, and a plurality of second electrode fingers 50 provided on the piezoelectric substrate 7 side. The first bus bar 10 is disposed opposite to the second bus bar 20, the plurality of first electrode fingers 40 are connected to the first bus bar 10 and extend toward the second bus bar 20, the plurality of second electrode fingers 50 are connected to the second bus bar 20 and extend toward the first bus bar 10, and the plurality of first electrode fingers 40 and the plurality of second electrode fingers 50 are alternately arranged in sequence.

In the present embodiment, the interdigital transducer 1 further includes a plurality of piston structures 60. At least one of the piston structures 60 is disposed on a surface of at least a portion of the first electrode fingers 40 facing away from the piezoelectric substrate 7, and the piston structure 60 is located at least at an end of the first electrode fingers 40 facing away from the first bus bar 10. At least one of the piston structures 60 is disposed on a surface of at least a portion of the second electrode fingers 50 facing away from the piezoelectric substrate 7, and the piston structure 60 is located at least at an end of the second electrode fingers 50 facing away from the second bus bar 20.

In an exemplary embodiment, at least one of the piston structures 60 on the first electrode fingers 40 includes two metal layers having different thicknesses, and at least one of the piston structures 60 on the second electrode fingers 50 includes two metal layers having different thicknesses.

In an exemplary embodiment, at least one of the plunger structures 60 may be disposed on a portion of the surface of the first electrode finger 40 facing away from the piezoelectric substrate 7, and at least one of the plunger structures 60 may be disposed on a portion of the surface of the second electrode finger 50 facing away from the piezoelectric substrate 7. It is also possible that at least one of the piston structures 60 is disposed on a surface of each of the first electrode fingers 40 facing away from the piezoelectric substrate 7 and at least one of the piston structures 60 is disposed on a surface of each of the second electrode fingers 50 facing away from the piezoelectric substrate 7, which is not particularly limited in this application.

It will be appreciated that by providing at least two metal layers of different thickness on the first electrode fingers 40 and at least two metal layers of different thickness on the second electrode fingers 50, a "well" region is formed in the region of acoustic signal generation, which confines acoustic energy to the region of the interdigital transducer 1 and suppresses excitation of transverse modes.

In an exemplary embodiment, at least one of the piston structures 60 on the first electrode finger 40 includes two metal layers of adjacent and different thicknesses, and at least one of the piston structures 60 on the second electrode finger 50 includes two metal layers of adjacent and different thicknesses. Alternatively, at least one of the piston structures 60 located on the first electrode finger 40 includes two metal layers having a predetermined distance therebetween and different thicknesses, and at least one of the piston structures 60 located on the second electrode finger 50 includes two metal layers having a predetermined distance therebetween and different thicknesses. This is not particularly limited by the present application.

In other embodiments of the present application, the piston structure 60 may be further disposed on a surface of the first electrode finger 40 facing the piezoelectric substrate 7 and a surface of the second electrode finger 50 facing the piezoelectric substrate 7, which is not particularly limited in the present application.

In an exemplary embodiment, the size of the first bus bar 10 is the same as the size of the second bus bar 20, i.e., the length, width and height of the first bus bar 10 are the same as the length, width and height of the second bus bar 20. The first electrode fingers 40 have the same size as the second electrode fingers 50, that is, the first electrode fingers 40 have the same length, width and height as the second electrode fingers 50.

In the exemplary embodiment, in the structure of the interdigital transducer 1, the duty ratio of the electrode fingers located on both sides is smaller than the duty ratio of the electrode fingers located in the middle along the direction of the alternate arrangement of the electrode fingers. Wherein, the duty ratio = the width of the electrode finger/the distance between the central lines of two adjacent electrode fingers.

In an exemplary embodiment, the first bus bar 10 is disposed opposite and parallel to the second bus bar 20, the first electrode fingers 40 are perpendicular to the first bus bar 10 and the second bus bar 20, respectively, and the second electrode fingers 50 are perpendicular to the first bus bar 10 and the second bus bar 20, respectively.

In an exemplary embodiment, the number of the first electrode fingers 40 may be 2 to 20, for example, 2, 6, 11, 16, 20, or another number, and in the embodiment of the present application, the number of the first electrode fingers 40 is 6 for example. The number of the second electrode fingers 50 may be 2 to 20, for example, 2, 5, 11, 15, 20, or another number, and in the embodiment of the present application, the number of the first electrode fingers 40 is 5 for example.

In an exemplary embodiment, the material of the piezoelectric substrate 7 may be aluminum nitride, zinc oxide, lead zirconate titanate (PZT), or a rare earth element doped material of the above materials at a certain atomic ratio. The piezoelectric substrate 7 may also be a single crystal piezoelectric material, such as single crystal aluminum nitride, lithium niobate, lithium tantalate, quartz, etc., which is not limited in this application.

In an exemplary embodiment, a single metal material or a composite or alloy material of different metals may be used for the material of the interdigital transducer 1 and the metal layer. The material of the interdigital transducer 1 and the metal layer may be one of molybdenum, tungsten, ruthenium, gold, magnesium, aluminum, copper, chromium, titanium, osmium, iridium, or a composite of the above metals or an alloy thereof, and the like, which is not particularly limited in the present application.

In the embodiment of the present application, the resonator 101 further includes reflective structures disposed on two opposite sides of the interdigital transducer, that is, the reflective structures are disposed on two ends of the first bus bar 10 and the second bus bar 20 in the length direction. It is understood that by disposing the reflection structures on both sides of the interdigital transducer 1, an acoustic wave signal can be reflected, so that the acoustic wave signal is confined between the two reflection structures, thereby improving the quality factor value of the resonator 101 and improving the performance of the resonator 101.

In summary, the resonator 101 provided in the embodiment of the present application includes the piezoelectric substrate 7 and the interdigital transducer 1. The interdigital transducer 1 includes a first bus bar 10, a second bus bar 20, a plurality of first electrode fingers 40, and a plurality of second electrode fingers 50. At least one piston structure 60 is disposed on the first electrode finger 40, and the piston structure 60 is located at least at an end of the first electrode finger 40 facing away from the first bus bar 10. At least one piston structure 60 is disposed on the second electrode finger 50, and the piston structure 60 is located at least at an end of the second electrode finger 50 facing away from the second bus bar 20. At least one of the piston structures 60 on the first electrode fingers 40 includes two metal layers having different thicknesses, and at least one of the piston structures 60 on the second electrode fingers 50 includes two metal layers having different thicknesses. Therefore, at least one piston structure 60 including two metal layers is disposed on the first electrode finger 40 and the second electrode finger 50, and the two metal layers are different from each other, so that the transmission speed of the acoustic wave signal on the piezoelectric substrate 7 in the region where the two metal layers are located is changed, and acoustic reflection is formed, and therefore, not only is the leakage of the acoustic wave signal avoided, but also the acoustic wave signal is limited in the interdigital transducer, so that the suppression of the transverse mode of the resonator 101 is improved, the acoustic energy loss is reduced, the quality factor value is improved, and the performance of the resonator 101 is improved.

In the embodiment of the present application, referring to fig. 2, the first electrode fingers 40 and the second electrode fingers 50 are sequentially and alternately arranged along the extending direction of the first bus bar 10 and the second bus bar 20 to form an alternating region, and the alternating region includes a first edge region Q1, a second edge region Q2, a middle region C, a third edge region Q3, and a fourth edge region Q4, which are sequentially and adjacently disposed in a direction from the first bus bar to the second bus bar.

It is understood that portions of the first electrode fingers 40 and portions of the second electrode fingers 50 overlap along the length direction of the first bus bar 10, and portions where a plurality of the first electrode fingers 40 overlap and portions where a plurality of the second electrode fingers 50 overlap form an alternating region.

In an exemplary embodiment, a longitudinal direction of the first edge region Q1, a longitudinal direction of the second edge region Q2, a longitudinal direction of the middle region C, a longitudinal direction of the third edge region Q3, and a longitudinal direction of the fourth edge region Q4 are parallel to a longitudinal direction of the first bus bar 10 and the second bus bar 20.

In an exemplary embodiment, gap regions are formed between the first edge region Q1 and the first bus bar 10 and between the fourth edge region Q4 and the second bus bar 20, respectively.

In the present embodiment, referring to fig. 2, at least one piston structure 60 disposed on at least a portion of the first electrode fingers 40 and at least a portion of the second electrode fingers 50 includes a first piston structure 80 and a second piston structure 90 disposed at intervals, the first piston structure 80 includes a first metal layer 81 and a second metal layer 82, and the second piston structure 90 includes a third metal layer 91 and a fourth metal layer 92. The thickness of the first metal layer 81 is different from that of the second metal layer 82, and the thickness of the third metal layer 91 is different from that of the fourth metal layer 92.

In the present embodiment, the third metal layer 91, the fourth metal layer 92, the first metal layer 81, and the second metal layer 82 are sequentially located in the first edge region Q1, the second edge region Q2, the third edge region Q3, and the fourth edge region Q4 along the extending direction of the first electrode finger 40, and the second metal layer 82 is located at an end of the first electrode finger 40 facing away from the first bus bar 10.

In the embodiment of the present application, the third metal layer 91, the fourth metal layer 92, the first metal layer 81, and the second metal layer 82 are sequentially located in the fourth edge region Q4, the third edge region Q3, the second edge region Q2, and the first edge region Q1 along the extending direction of the second electrode finger 50, and the second metal layer 82 is located at an end of the second electrode finger 50 facing away from the second bus bar 20.

In an exemplary embodiment, the first metal layers 81 on the plurality of first electrode fingers 40 and the fourth metal layers 92 on the plurality of second electrode fingers 50 are alternately arranged side by side and within the third edge region Q3, and the second metal layers 82 on the plurality of first electrode fingers 40 and the third metal layers 91 on the plurality of second electrode fingers 50 are alternately arranged side by side and within the fourth edge region Q4. The third metal layers 91 on the plurality of first electrode fingers 40 and the second metal layers 82 on the plurality of second electrode fingers 50 are alternately disposed side by side and within the first edge region Q1, and the fourth metal layers 92 on the plurality of first electrode fingers 40 and the first metal layers 81 on the plurality of second electrode fingers 50 are alternately disposed side by side and within the second edge region Q2.

In an exemplary embodiment, the third metal layer 91 is disposed adjacent to the fourth metal layer 92, and the first metal layer 81 is disposed adjacent to the second metal layer 82. Or, the third metal layer 91 and the fourth metal layer 92 are separated by a predetermined distance, and the first metal layer 81 and the second metal layer 82 are separated by a predetermined distance.

In an exemplary embodiment, the material of the metal layer may be the same as or different from that of the interdigital transducer, the material of the first metal layer 81 may be the same as or different from that of the second metal layer 82, and the material of the third metal layer 91 may be the same as or different from that of the fourth metal layer 92.

In an exemplary embodiment, the metal layer may be fabricated by a process of paste coating, exposure, development, metal deposition, wet stripping, and the like. The first metal layer 81 and the second metal layer 82 may be integrally formed, and the third metal 91 and the fourth metal layer 92 may be integrally formed and formed into metal layer structures having different thicknesses by an etching process.

Referring to fig. 3 and 4, fig. 3 is a schematic diagram illustrating a layer structure of a second resonator according to an embodiment of the present application, and fig. 4 is a schematic diagram illustrating a front view structure of an interdigital transducer of the resonator shown in fig. 3. The second resonator 102 differs from the first resonator 101 in that: the first piston structure 80 of the interdigital transducer 1 of the second resonator 102 includes only the first metal layer 81 and does not include the second metal layer 82. For the description of the parts of the second resonator 102 that are the same as the parts of the first resonator 101, please refer to the description of the first resonator 101, and the description thereof is omitted here.

In the embodiment of the present application, each of the at least one piston structure 60 disposed on at least a portion of the first electrode fingers 40 and at least a portion of the second electrode fingers 50 includes a first piston structure 80 and a second piston structure 90 disposed at intervals, the first piston structure 80 includes a first metal layer 81, and the second piston structure 90 includes a third metal layer 91 and a fourth metal layer 92. Wherein the third metal layer 91 and the fourth metal layer 92 have different thicknesses.

In the embodiment of the present application, the third metal layer 91, the fourth metal layer 92, and the first metal layer 81 are sequentially located in the first edge region Q1, the second edge region Q2, and the third edge region Q3 along the extending direction of the first electrode finger 40. The third metal layer 91, the fourth metal layer 92, and the first metal layer 81 are sequentially located in the fourth edge area Q4, the third edge area Q3, and the second edge area Q2 along the extending direction of the second electrode finger 50.

In an exemplary embodiment, the first metal layers 81 on the plurality of first electrode fingers 40 and the fourth metal layers 92 on the plurality of second electrode fingers 50 are alternately disposed side by side and within the third edge region Q3, and the third metal layers 91 on the plurality of second electrode fingers 50 are disposed side by side and within the fourth edge region Q4. The third metal layers 91 on the plurality of first electrode fingers 40 are disposed side by side at intervals and located in the first edge region Q1, and the fourth metal layers 92 on the plurality of first electrode fingers 40 and the first metal layers 81 on the plurality of second electrode fingers 50 are disposed side by side at intervals and located in the second edge region Q2.

Referring to fig. 5 and 6, fig. 5 is a schematic diagram illustrating a layer structure of a third resonator according to an embodiment of the present application, and fig. 6 is a schematic diagram illustrating a front view of an interdigital transducer of the resonator shown in fig. 5. The third resonator 103 differs from the first resonator 101 in that: the first piston structure 80 of the interdigital transducer 1 of the third resonator 103 includes only the second metal layer 82 and does not include the first metal layer 81. For the description of the third resonator 103 and the first resonator 101, please refer to the description of the first resonator 101, and the description is omitted here.

In the embodiment of the present application, each of the at least one piston structure 60 disposed on at least a portion of the first electrode fingers 40 and at least a portion of the second electrode fingers 50 includes a first piston structure 80 and a second piston structure 90 disposed at intervals, the first piston structure 80 includes a second metal layer 82, and the second piston structure 90 includes a third metal layer 91 and a fourth metal layer 92. Wherein the third metal layer 91 and the fourth metal layer 92 have different thicknesses.

In the embodiment of the present application, the third metal layer 91, the fourth metal layer 92, and the second metal layer 82 are sequentially located in the first edge region Q1, the second edge region Q2, and the fourth edge region Q4 along the extending direction of the first electrode finger 40, and the second metal layer 82 is located at an end of the first electrode finger 40 facing away from the first bus bar 10.

In the embodiment of the present application, the third metal layer 91, the fourth metal layer 92, and the second metal layer 82 are sequentially located in the fourth edge area Q4, the third edge area Q3, and the first edge area Q1 along the extending direction of the second electrode finger 50, and the second metal layer 82 is located at an end of the second electrode finger 50 facing away from the second bus bar 20.

In an exemplary embodiment, the fourth metal layers 92 of the plurality of second electrode fingers 50 are spaced side by side and located in the third edge region Q3, and the second metal layers 82 of the plurality of first electrode fingers 40 and the third metal layers 91 of the plurality of second electrode fingers 50 are alternately spaced side by side and located in the fourth edge region Q4. The third metal layers 91 on the plurality of first electrode fingers 40 and the second metal layers 82 on the plurality of second electrode fingers 50 are alternately arranged side by side and in the first edge region Q1, and the fourth metal layers 92 on the plurality of first electrode fingers 40 are arranged side by side and in the second edge region Q2.

Referring to fig. 7 and 8, fig. 7 is a schematic diagram of a layer structure of a fourth resonator according to an embodiment of the disclosure, and fig. 8 is a schematic diagram of a front view of an interdigital transducer of the resonator shown in fig. 7. The fourth resonator 104 differs from the first resonator 101 in that: the interdigital transducer 1 of the fourth resonator 104 comprises only the first piston structure 80 and no second piston structure 90. For the description of the fourth resonator 104 in the same place as the first resonator 101, please refer to the description of the first resonator 101, and the description is omitted here.

In the present embodiment, the at least one piston structure 60 disposed on at least a portion of the first electrode fingers 40 and at least a portion of the second electrode fingers 50 each includes a first piston structure 80, and the first piston structure 80 includes a first metal layer 81 and a second metal layer 82. Wherein the thickness of the first metal layer 81 is different from the thickness of the second metal layer 82.

In the embodiment of the present application, the first metal layer 81 and the second metal layer 82 are sequentially located in the third edge region Q3 and the fourth edge region Q4 along the extending direction of the first electrode finger 40, and the second metal layer 82 is located at an end of the first electrode finger 40 facing away from the first bus bar 10. The first metal layer 81 and the second metal layer 82 are sequentially located in the second edge region Q2 and the first edge region Q1 along the extending direction of the second electrode finger 50, and the second metal layer 82 is located at an end of the second electrode finger 50 facing away from the second bus bar 20.

In an exemplary embodiment, the first metal layers 81 on the plurality of first electrode fingers 40 are alternately arranged side by side and located in the third edge region Q3, and the second metal layers 82 on the plurality of first electrode fingers 40 are alternately arranged side by side and located in the fourth edge region Q4. The second metal layers 82 on the plurality of second electrode fingers 50 are arranged side by side at intervals and located in the first edge region Q1, and the first metal layers 81 on the plurality of second electrode fingers 50 are arranged side by side at intervals and located in the second edge region Q2.

Referring to fig. 1, fig. 3, fig. 5 and fig. 7, in the embodiment of the present invention, the thickness of the metal layer located in the first edge region Q1 is greater than the thickness of the metal layer located in the second edge region Q2, and the thickness of the metal layer located in the fourth edge region Q4 is greater than the thickness of the metal layer located in the third edge region Q3.

In an exemplary embodiment, the thickness of the second metal layer 82 is greater than the thickness of the first metal layer 81, and the thickness of the third metal layer 91 is greater than the thickness of the fourth metal layer 92.

In an exemplary embodiment, the thickness of the metal layer located in the first edge region Q1 and the thickness of the metal layer located in the fourth edge region Q4 may be equal or different; the thickness of the metal layer located in the second edge region Q2 and the thickness of the metal layer located in the third edge region Q3 may be equal or different, which is not limited in this embodiment of the present application.

Referring to fig. 2, 4, 6 and 8, in the embodiment of the present invention, a ratio of a length of the metal layer located in the first edge region Q1 to a length of the metal layer located in the second edge region Q2 is 0.8 to 1.2; the ratio of the length of the metal layer located in the fourth edge region Q4 to the length of the metal layer located in the third edge region Q3 is 0.8 to 1.2.

In the embodiment of the present application, the ratio of the length of the second metal layer 82 to the length of the first metal layer 81 is 0.8 to 1.2, for example, 0.8, 0.9, 1, 1.1, 1.2, or other values, which is not particularly limited in the present application. The ratio of the length of the third metal layer 91 to the length of the fourth metal layer 92 is 0.8 to 1.2, for example, 0.8, 0.9, 1, 1.1, 1.2, or other values, which is not limited in this application.

In an exemplary embodiment, the length of the second metal layer 82 is the same as the length of the third metal layer 91, and the length of the first metal layer 81 is the same as the length of the fourth metal layer 92.

In an exemplary embodiment, the length of the metal layer located in the first edge region Q1 and the length of the metal layer located in the fourth edge region Q4 may or may not be equal; the length of the metal layer located in the second edge region Q2 and the length of the metal layer located in the third edge region Q3 may be equal or different, which is not limited in this embodiment of the application.

In the embodiment of the present application, the ratio of the width of the metal layer located in the first edge region Q1 to the width of the metal layer located in the second edge region Q2 is 0.8 to 1.2; the ratio of the width of the metal layer located in the fourth edge region Q4 to the width of the metal layer located in the third edge region Q3 is 0.8 to 1.2.

In the present embodiment, the ratio of the width of the second metal layer 82 to the width of the first metal layer 81 is 0.8 to 1.2, for example, 0.8, 0.9, 1, 1.1, 1.2, or other values, which is not limited in the present application. The ratio of the width of the third metal layer 91 to the width of the fourth metal layer 92 is 0.8 to 1.2, for example, 0.8, 0.9, 1, 1.1, 1.2, or other values, which is not particularly limited in this application.

In an exemplary embodiment, the width of the second metal layer 82 is the same as the width of the third metal layer 91, and the width of the first metal layer 81 is the same as the width of the fourth metal layer 92.

In an exemplary embodiment, the width of the metal layer located in the first edge region Q1 and the width of the metal layer located in the fourth edge region Q4 may be equal or different; the width of the metal layer located in the second edge region Q2 and the width of the metal layer located in the third edge region Q3 may be equal or different, which is not limited in this embodiment of the application.

In the embodiment of the present application, a ratio of a thickness of the metal layer located in the first edge region to a thickness of the metal layer located in the second edge region is 1.2 to 5; the ratio of the thickness of the metal layer located at the fourth edge region to the thickness of the metal layer located at the third edge region is 1.2 to 5.

In the embodiment of the present application, the ratio of the thickness of the second metal layer 82 to the thickness of the first metal layer 81 is 1.2 to 5, for example, 1.2, 2, 3.2, 4.3, 5, or other values, which is not particularly limited in the present application. The ratio of the thickness of the third metal layer 91 to the thickness of the fourth metal layer 92 is 1.2 to 5, for example, 1.2, 2, 3, 3.2, 4.3, 5, or other values, which is not particularly limited in this application.

It is understood that there is a certain thickness difference between the second metal layer 82 and the first metal layer 81, and there is a certain thickness difference between the third metal layer 91 and the fourth metal layer 92, and the difference is not too large. The thickness of the second metal layer 82 needs to be greater than that of the first metal layer 81, the thickness of the third metal layer 91 is greater than that of the fourth metal layer 92, and the ratio of the two is not too large; if the ratio is too large, the effect of suppressing the transverse mode is also obtained, but the quality factor at the anti-resonance point is too low. When the ratio of the thickness of the second metal layer 82 to the thickness of the first metal layer 81 is 1.2 to 5, and the ratio of the thickness of the third metal layer 91 to the thickness of the fourth metal layer 92 is 1.2 to 5, a good transverse mode suppression effect can be obtained, and a quality factor value can be effectively improved.

In an exemplary embodiment, the thickness of the second metal layer 82 is the same as the thickness of the third metal layer 91, and the thickness of the first metal layer 81 is the same as the thickness of the fourth metal layer 92.

In an exemplary embodiment, the thickness of the metal layer located in the first edge region Q1 and the thickness of the metal layer located in the fourth edge region Q4 may be equal or different; the thickness of the metal layer located in the second edge region Q2 and the thickness of the metal layer located in the third edge region Q3 may be equal or different, which is not limited in this embodiment of the application.

In this embodiment, a ratio of a length of the metal layer located in the first edge region to a length of the metal layer located in the second edge region is 1, and a ratio of a length of the metal layer located in the fourth edge region to a length of the metal layer located in the third edge region is 1.

In this embodiment, a ratio of a width of the metal layer located in the first edge region to a width of the metal layer located in the second edge region is 1, and a ratio of a width of the metal layer located in the fourth edge region to a width of the metal layer located in the third edge region is 1.

In this embodiment, a ratio of a thickness of the metal layer located in the first edge region to a thickness of the metal layer located in the second edge region is 2, and a ratio of a thickness of the metal layer located in the fourth edge region to a thickness of the metal layer located in the third edge region is 2.

In the embodiment of the present application, a ratio of the length of the second metal layer 82 to the length of the first metal layer 81 is 1, and a ratio of the length of the third metal layer 91 to the length of the fourth metal layer 92 is 1. The ratio of the width of the second metal layer 82 to the width of the first metal layer 81 is 1, and the ratio of the width of the third metal layer 91 to the width of the fourth metal layer 92 is 1. The ratio of the thickness of the second metal layer 82 to the thickness of the first metal layer 81 is 2, and the ratio of the thickness of the third metal layer 91 to the thickness of the fourth metal layer 92 is 2.

In an exemplary embodiment, the length, thickness, and width of the metal layer located in the first edge region Q1 may or may not be equal to the length, thickness, and width of the metal layer located in the fourth edge region Q4, respectively; the length, thickness, and width of the metal layer located in the second edge region Q2 may be equal to or different from the length, thickness, and width of the metal layer located in the third edge region Q3, respectively, which is not limited in this embodiment of the application.

Referring to fig. 9 to 11, fig. 9 is a schematic diagram of an admittance curve corresponding to a first preferred structural parameter of an interdigital transducer disclosed in the present application, fig. 10 is a schematic diagram of an admittance curve corresponding to a second preferred structural parameter of an interdigital transducer disclosed in the present application, and fig. 11 is a schematic diagram of an admittance curve corresponding to a third preferred structural parameter of an interdigital transducer disclosed in the present application.

In the embodiment of the present application, the metal layer length is adjusted while controlling the width and thickness of the metal layer to be constant. The first preferred structural parameters correspond to: the ratio of the length of the second metal layer 82 to the length of the first metal layer 81 is 1, and the ratio of the length of the third metal layer 91 to the length of the fourth metal layer 92 is 1. As can be seen from fig. 9, when the structural parameter of the interdigital transducer 1 is the first preferred structural parameter, the admittance curve between the resonance point and the anti-resonance point is smooth, there is no clutter, and the admittance real-part curve has no sharp peak between the resonance point and the anti-resonance point, so that the transverse mode can be well suppressed.

In the embodiment of the present application, the metal layer width is adjusted while controlling the length and thickness of the metal layer to be constant. The second preferred structural parameters correspond to: the ratio of the width of the second metal layer 82 to the width of the first metal layer 81 is 1, and the ratio of the width of the third metal layer 91 to the width of the fourth metal layer 92 is 1. As can be seen from fig. 10, when the structural parameter of the interdigital transducer 1 is the second preferred structural parameter, the admittance curve between the resonance point and the anti-resonance point is smooth, there is no clutter, and the admittance real-part curve has no sharp peak between the resonance point and the anti-resonance point, so that the transverse mode can be well suppressed.

In the embodiment of the present application, the thickness of the metal layer is adjusted while controlling the length and width of the metal layer to be constant. The third preferred structural parameter corresponds to: the ratio of the thickness of the second metal layer 82 to the thickness of the first metal layer 81 is 2, and the ratio of the thickness of the third metal layer 91 to the thickness of the fourth metal layer 92 is 2. Referring to fig. 11 and 12 together, fig. 12 is a schematic diagram of admittance curves corresponding to the structural parameters of the prior art interdigital transducer, and the structural parameters of the prior art interdigital transducer are different from the third preferred structural parameters in that: the prior art piston structure has only one metal layer. As can be seen from fig. 11, when the structural parameter of the interdigital transducer 1 is the third preferred structural parameter, the admittance curve between the resonance point and the anti-resonance point is smooth, no clutter exists, and the admittance real part curve has no sharp peak between the resonance point and the anti-resonance point, so that the transverse mode can be well suppressed. As can be seen from fig. 12, clutter exists between the resonance point and the anti-resonance point of the prior art interdigital transducer, and the real-admittance curve has a relatively sharp peak at the resonance point, thereby causing excitation of transverse modes.

Referring to fig. 13 to 16, fig. 13 is a schematic diagram of sound velocity distribution corresponding to each region in the resonator shown in fig. 1, fig. 14 is a schematic diagram of sound velocity distribution corresponding to each region in the resonator shown in fig. 3, fig. 15 is a schematic diagram of sound velocity distribution corresponding to each region in the resonator shown in fig. 5, and fig. 16 is a schematic diagram of sound velocity distribution corresponding to each region in the resonator shown in fig. 7.

In this embodiment of the present application, the sound velocity corresponding to the middle region C is greater than the sound velocity corresponding to the first edge region Q1 and the sound velocity corresponding to the second edge region Q2, and the sound velocity corresponding to the first edge region Q1 is different from the sound velocity corresponding to the second edge region Q2. The sound velocity corresponding to the middle region C is greater than the sound velocity corresponding to the third edge region Q3 and the sound velocity corresponding to the fourth edge region Q4, and the sound velocity corresponding to the third edge region Q3 is different from the sound velocity corresponding to the fourth edge region Q4.

In the embodiment of the present application, the sound velocity corresponding to the second edge region Q2 is greater than the sound velocity corresponding to the first edge region Q1, and the sound velocity corresponding to the third edge region Q3 is greater than the sound velocity corresponding to the fourth edge region Q4.

It will be appreciated that the greater the thickness of the metal layer, the lower the speed of sound corresponding to the edge region.

In an exemplary embodiment, the sound velocity corresponding to the first edge region Q1 is equal to the sound velocity corresponding to the fourth edge region Q4, and the sound velocity corresponding to the second edge region Q2 is equal to the sound velocity corresponding to the third edge region Q3.

In the embodiment of the present application, referring to fig. 2, fig. 4, fig. 6 and fig. 8, the width of the metal layer on the first electrode finger 40 is smaller than or equal to the width of the first electrode finger, and the width of the metal layer on the second electrode finger 50 is smaller than or equal to the width of the second electrode finger.

In the embodiment, the width of the third metal layer 91 and the width of the fourth metal layer 92 on the first electrode finger 40 are less than or equal to the width of the first electrode finger 40, and the width of the first metal layer 81 and the width of the second metal layer 82 on the first electrode finger 40 are less than or equal to the width of the first electrode finger 40.

In the embodiment, the width of the third metal layer 91 and the width of the fourth metal layer 92 on the second electrode finger 50 are less than or equal to the width of the second electrode finger 50, and the width of the first metal layer 81 and the width of the second metal layer 82 on the second electrode finger 50 are less than or equal to the width of the second electrode finger 50.

In the embodiment of the present application, referring to fig. 1, fig. 3, fig. 5 and fig. 7, the thickness of the metal layer on the first electrode finger 40 is smaller than the thickness of the first electrode finger; the thickness of the metal layer on the second electrode finger 50 is smaller than the thickness of the second electrode finger.

In the embodiment, the thickness of the third metal layer 91 and the thickness of the fourth metal layer 92 on the first electrode finger 40 are smaller than the thickness of the first electrode finger 40, and the thickness of the first metal layer 81 and the thickness of the second metal layer 82 on the first electrode finger 40 are smaller than the thickness of the first electrode finger 40.

In the embodiment, the thickness of the third metal layer 91 and the thickness of the fourth metal layer 92 on the second electrode finger 50 are smaller than the thickness of the second electrode finger 50, and the thickness of the first metal layer 81 and the thickness of the second metal layer 82 on the second electrode finger 50 are smaller than the thickness of the second electrode finger 50.

In the present embodiment, please refer to fig. 17 and 18, fig. 17 is a schematic diagram illustrating a fifth layer structure of a resonator disclosed in the present embodiment, and fig. 18 is a schematic diagram illustrating a front view structure of an interdigital transducer of the resonator shown in fig. 17. The fifth resonator 105 differs from the first resonator 101 in that: the interdigital transducer 1 of the fifth resonator 105 further includes a plurality of first dummy fingers 130 and a plurality of second dummy fingers 140. For the description of the fifth resonator 105 being the same as the first resonator 101, please refer to the description of the first resonator 101, and the description thereof is omitted here.

In the embodiment, the interdigital transducer 1 further includes a plurality of first dummy fingers 130 and a plurality of second dummy fingers 140, the first dummy fingers 130 are disposed between the first electrode fingers 40 and the second bus bar 20, and the first dummy fingers 130 are connected to the second bus bar 20. The second dummy finger 140 is disposed between the second electrode finger 50 and the first bus bar 10, and the second dummy finger 140 is connected to the first bus bar 10.

It is understood that the first artificial finger 130 and the second artificial finger 140 are provided on the interdigital transducer 1, and a low-speed region can be further formed in the region where the first artificial finger 130 and the second artificial finger 140 are located, so that the transverse mode of the resonator 101 can be further suppressed.

In an exemplary embodiment, the first electrode fingers 40 and the second dummy fingers 140 are alternately arranged along the length direction of the first bus bar 10, the length of the second dummy fingers 140 is smaller than that of the first electrode fingers 40, and the width and height of the second dummy fingers 140 are equal to those of the first electrode fingers 40. The plurality of second electrode fingers 50 and the plurality of first dummy fingers 130 are alternately arranged along the length direction of the second bus bar 20, the length of the first dummy fingers 130 is smaller than that of the second electrode fingers 50, and the width and height of the first dummy fingers 130 are equal to those of the second electrode fingers 50.

In an exemplary embodiment, the first dummy fingers 130 are disposed in parallel with the first electrode fingers 40, and the number of the first dummy fingers 130 is the same as the number of the first electrode fingers 40. The second dummy fingers 140 are disposed in parallel with the second electrode fingers 50, and the number of the second dummy fingers 140 is the same as that of the second electrode fingers 50. The length, width and height of the first artificial finger 130 are equal to the length, width and height of the second artificial finger 140.

In the embodiments of the present application, please refer to fig. 1, fig. 3, fig. 5, fig. 7, and fig. 16. The resonator 101 further comprises a temperature compensation layer 9, and the interdigital transducer 1 is covered on the piezoelectric substrate 7 by the temperature compensation layer 9. The temperature compensation layer 9 is used to adjust the temperature frequency coefficient of the resonator 101 to avoid the change of the resonant frequency of the resonator due to the temperature change.

In an exemplary embodiment, the temperature compensation layer 9 may have a positive temperature coefficient to compensate for a negative temperature coefficient of the piezoelectric substrate 7. The material of the temperature compensation layer 9 includes, but is not limited to, silicon dioxide, fluorine-containing silicon dioxide, silicon nitride-based silicon-containing dielectric film, and the like.

In an exemplary embodiment, the resonator 101 may further include a passivation layer (not shown) and/or a frequency modulation layer (not shown), the passivation layer and/or the frequency modulation layer are located on a side of the temperature compensation layer 9 opposite to the piezoelectric substrate 7, and the material of the passivation layer and the frequency modulation layer includes, but is not limited to, silicon nitride (Si 3N 4) and the like.

In an exemplary embodiment, the resonator 101 may be a Temperature Compensated surface acoustic wave filter (TC-SAW).

In an exemplary embodiment, the interdigital transducer 1 may also be applied to a laterally excited thin Film Bulk Acoustic Resonator (X-BAR). Referring to fig. 19, fig. 19 is a schematic structural diagram of a sixth resonator according to an embodiment of the present disclosure. The sixth resonator 106 differs from the first resonator 101 in that: the interdigital transducer 1 of the sixth resonator 106 further comprises a substrate. The resonator 106 includes a substrate 8, a piezoelectric substrate 7, and an interdigital transducer 1, which are stacked in sequence, where a cavity is formed on the substrate 8, the cavity penetrates from the upper surface to the lower surface of the substrate 8, and the upper surface is a surface on which the piezoelectric substrate 7 is disposed. For the description of the sixth resonator 106 in the same place as the first resonator 101, please refer to the description of the first resonator 101, and the description is omitted here.

In an exemplary embodiment, the structure of a laterally excited thin Film Bulk Acoustic Resonator (X-BAR) may also be: an opening window is formed on the substrate, the opening direction of the opening window is the surface provided with the piezoelectric substrate 7, and the piezoelectric substrate 7 covers the opening window.

In another embodiment of the present application, the alternating regions include at least two fifth edge regions, a middle region, and at least two sixth edge regions, which are sequentially arranged in a direction from the first bus bar 10 toward the second bus bar 20.

the sound velocities corresponding to the at least two fifth edge regions arranged in sequence from the middle region to the direction of the first bus bar 10 decrease in sequence;

the sound velocities corresponding to the at least two sixth edge regions arranged in sequence from the middle region toward the direction of the second bus bar 20 decrease in sequence.

In an exemplary embodiment, the metal layers are respectively disposed in the at least two fifth edge regions and the at least two sixth edge regions, and the thickness relationship, the width relationship, and the like between the metal layers can be controlled, so that the sound velocities corresponding to the at least two fifth edge regions sequentially arranged from the middle region to the direction of the first bus bar 10 are sequentially reduced, and the sound velocities corresponding to the at least two sixth edge regions sequentially arranged from the middle region to the direction of the second bus bar 20 are sequentially reduced.

Referring to fig. 20, based on the same inventive concept, fig. 20 is a schematic structural diagram of a filter disclosed in an embodiment of the present application. The embodiment of the present application further provides a filter 200, where the filter 200 at least includes a plurality of resonators 101 as described above.

IN the present embodiment, the filter may further include at least an input terminal IN, an output terminal OUT, a series branch Bl, and at least one parallel branch B2. The series branch Bl is connected between the input end IN and the output end OUT, one end of the parallel branch B2 is connected with the series branch Bl, and the other end is connected with a ground end GND; at least two resonators 101 connected in series are arranged in the series branch Bl, and the resonators 101 connected in parallel are arranged in each parallel branch B2.

In the embodiment of the present application, the filter 200 is exemplified to include the first resonator 101. The filter 200 may further include a second resonator 102, a third resonator 103, a fourth resonator 104, a fifth resonator 105, and a sixth resonator 106, which is not particularly limited in this application. Since the embodiments shown in fig. 1 to 19 have already been described in detail with respect to the resonator, no further details are given here.

In summary, the filter 200 provided in the embodiment of the present application includes a plurality of resonators 101, where the resonators 101 include a piezoelectric substrate 7 and an interdigital transducer 1. The interdigital transducer 1 includes a first bus bar 10, a second bus bar 20, a plurality of first electrode fingers 40, and a plurality of second electrode fingers 50. At least one piston structure 60 is disposed on the first electrode finger 40, and the piston structure 60 is located at least at an end of the first electrode finger 40 facing away from the first bus bar 10. At least one piston structure 60 is disposed on the second electrode finger 50, and the piston structure 60 is located at least at an end of the second electrode finger 50 facing away from the second bus bar 20. At least one of the piston structures 60 on the first electrode fingers 40 includes two metal layers having different thicknesses, and at least one of the piston structures 60 on the second electrode fingers 50 includes two metal layers having different thicknesses. Therefore, at least one piston structure 60 including two metal layers is disposed on the first electrode finger 40 and the second electrode finger 50, and the two metal layers are different, so that the transmission speed of the sound wave signal on the piezoelectric substrate 7 in the region where the two metal layers are located is changed, and acoustic reflection is formed; therefore, the leakage of the acoustic wave signal is avoided, the acoustic wave signal is limited in the interdigital transducer, and the suppression of the transverse mode of the resonator 101 is further improved; acoustic energy losses are reduced, quality factor values are improved and the performance of the resonator 101 is improved.

Based on the same inventive concept, the embodiment of the present application further provides an electronic device, which includes a substrate and the above-mentioned filter 200, wherein the filter 200 is flip-mounted on the substrate and is electrically connected to the substrate.

In an exemplary embodiment, the substrate may be a Printed Circuit Board (PCB).

In an exemplary embodiment, the electronic device includes, but is not limited to: any electronic device or component with a PCBA board assembly, such as an LED panel, a tablet computer, a notebook computer, a navigator, a mobile phone, and an electronic watch, is not particularly limited in this application.

It is understood that the electronic device may also include an electronic device such as a Personal Digital Assistant (PDA) and/or a music player, such as a mobile phone, a tablet computer, a wearable electronic device with wireless communication function (e.g., a smart watch), and the like. The electronic device may also be other electronic devices such as a Laptop computer (Laptop) with a touch sensitive surface (e.g., a touch panel), etc. In some embodiments, the electronic device may have a communication function, that is, may establish communication with a network through a 2G (second generation mobile phone communication specification), a 3G (third generation mobile phone communication specification), a 4G (fourth generation mobile phone communication specification), a 5G (fifth generation mobile phone communication specification), or a W-LAN (wireless local area network) or a communication method that may appear in the future. For the sake of brevity, no further limitations are imposed on this embodiment of the present application.

Since the embodiments shown in fig. 1 to 20 have been described in detail with respect to the resonator and the filter 200, no further description is provided.

In summary, the electronic device provided by the embodiment of the present application includes a filter 200, the filter includes a plurality of resonators 101, and the resonators 101 include a piezoelectric substrate 7 and an interdigital transducer 1. The interdigital transducer 1 includes a first bus bar 10, a second bus bar 20, a plurality of first electrode fingers 40, and a plurality of second electrode fingers 50. At least one piston structure 60 is disposed on the first electrode finger 40, and the piston structure 60 is located at least at an end of the first electrode finger 40 facing away from the first bus bar 10. At least one piston structure 60 is disposed on the second electrode finger 50, and the piston structure 60 is located at least at an end of the second electrode finger 50 facing away from the second bus bar 20. At least one of the piston structures 60 on the first electrode finger 40 includes two metal layers having different thicknesses, and at least one of the piston structures 60 on the second electrode finger 50 includes two metal layers having different thicknesses. Therefore, at least one piston structure 60 including two metal layers is disposed on the first electrode finger 40 and the second electrode finger 50, and the two metal layers are different, so that the transmission speed of the sound wave signal on the piezoelectric substrate 7 in the region where the two metal layers are located is changed, and acoustic reflection is formed; therefore, the leakage of the acoustic wave signal is avoided, the acoustic wave signal is limited in the interdigital transducer, and the suppression of the transverse mode of the resonator 101 is further improved; acoustic energy losses are reduced, quality factor values are improved and the performance of the resonator 101 is improved.

In the description herein, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example" or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

It should be understood that the application of the present application is not limited to the above examples, and that modifications or changes may be made by those skilled in the art based on the above description, and all such modifications and changes are intended to fall within the scope of the appended claims. All or a portion of the methods to implement the embodiments described above and equivalents thereof to the claims of this application will be understood by those skilled in the art and still fall within the scope of the invention.

Claims

1. A resonator comprising a piezoelectric substrate, an interdigital transducer located on the piezoelectric substrate, and a reflective structure disposed on opposite sides of the interdigital transducer, wherein the interdigital transducer comprises:

the first bus bar and the second bus bar are oppositely arranged;

2. The resonator of claim 1, wherein at least one of the piston structures on the first electrode finger comprises two metal layers of adjacent and different thicknesses, and at least one of the piston structures on the second electrode finger comprises two metal layers of adjacent and different thicknesses; or,

at least one of the piston structures located on the first electrode finger includes two metal layers having a preset distance and different thicknesses, and at least one of the piston structures located on the second electrode finger includes two metal layers having a preset distance and different thicknesses.

3. The resonator according to claim 2, wherein a plurality of the first electrode fingers and a plurality of the second electrode fingers are alternately arranged in sequence along an extending direction of the first bus bar and the second bus bar to form an alternate region, and the alternate region includes a first edge region, a second edge region, a middle region, a third edge region, and a fourth edge region which are sequentially arranged in a direction from the first bus bar to the second bus bar.

4. The resonator of claim 3, wherein the at least one piston structure disposed on at least a portion of the first electrode fingers and at least a portion of the second electrode fingers each comprises a first piston structure and a second piston structure disposed in a spaced apart relationship, the first piston structure comprising a first metal layer and a second metal layer, the second piston structure comprising a third metal layer and a fourth metal layer, wherein the first metal layer has a thickness different from a thickness of the second metal layer, and the third metal layer has a thickness different from a thickness of the fourth metal layer; the third metal layer, the fourth metal layer, the first metal layer and the second metal layer are sequentially located in the first edge area, the second edge area, the third edge area and the fourth edge area along the extending direction of the first electrode finger, and the second metal layer is located at the end of the first electrode finger opposite to the first bus bar;

the third metal layer, the fourth metal layer, the first metal layer and the second metal layer are sequentially located in the fourth edge area, the third edge area, the second edge area and the first edge area along the extending direction of the second electrode finger, and the second metal layer is located at the end portion, back to the second bus bar, of the second electrode finger.

5. The resonator of claim 3, wherein the at least one piston structure disposed on at least a portion of the first electrode fingers and at least a portion of the second electrode fingers each comprise a first piston structure and a second piston structure disposed in a spaced-apart relationship, the first piston structure comprising a first metal layer, the second piston structure comprising a third metal layer and a fourth metal layer, wherein the third metal layer is a different thickness than the fourth metal layer;

the third metal layer, the fourth metal layer and the first metal layer are sequentially located in the first edge area, the second edge area and the third edge area along the extending direction of the first electrode finger; the third metal layer, the fourth metal layer and the first metal layer are sequentially located in the fourth edge area, the third edge area and the second edge area along the extending direction of the second electrode finger.

6. The resonator of claim 3, wherein the at least one piston structure disposed on at least a portion of the first electrode fingers and at least a portion of the second electrode fingers each comprise a first piston structure and a second piston structure disposed in a spaced-apart relationship, the first piston structure comprising a second metal layer, the second piston structure comprising a third metal layer and a fourth metal layer, wherein the third metal layer is a different thickness than the fourth metal layer;

the third metal layer, the fourth metal layer and the second metal layer are sequentially located in the first edge area, the second edge area and the fourth edge area along the extending direction of the first electrode finger, and the second metal layer is located at the end of the first electrode finger, which faces away from the first bus bar;

the third metal layer, the fourth metal layer and the second metal layer are sequentially located in the fourth edge area, the third edge area and the first edge area along the extending direction of the second electrode finger, and the second metal layer is located at the end portion of the second electrode finger, which faces away from the second bus bar.

7. The resonator of claim 3, wherein the at least one piston structure disposed on at least a portion of the first electrode fingers and at least a portion of the second electrode fingers each comprises a first piston structure comprising a first metal layer and a second metal layer, wherein the first metal layer has a thickness different from a thickness of the second metal layer;

the first metal layer and the second metal layer are sequentially located in the third edge region and the fourth edge region along the extending direction of the first electrode finger, and the second metal layer is located at an end portion of the first electrode finger, which faces away from the first bus bar; the first metal layer and the second metal layer are sequentially located in the second edge region and the first edge region along an extending direction of the second electrode finger, and the second metal layer is located at an end portion of the second electrode finger, which faces away from the second bus bar.

8. The resonator of any of claims 4-7, wherein a thickness of the metal layer at the first edge region is greater than a thickness of the metal layer at the second edge region, and a thickness of the metal layer at the fourth edge region is greater than a thickness of the metal layer at the third edge region.

9. The resonator of any of claims 4-7, wherein a ratio of a length of the metal layer at the first edge region to a length of the metal layer at the second edge region is 0.8 to 1.2; the ratio of the length of the metal layer located in the fourth edge region to the length of the metal layer located in the third edge region is 0.8 to 1.2.

10. The resonator of any of claims 4-7, wherein a ratio of a width of the metal layer at the first edge region to a width of the metal layer at the second edge region is 0.8 to 1.2; the ratio of the width of the metal layer located in the fourth edge region to the width of the metal layer located in the third edge region is 0.8 to 1.2.

11. The resonator of any of claims 4-7, wherein a ratio of a thickness of the metal layer at the first edge region to a thickness of the metal layer at the second edge region is 1.2 to 5; the ratio of the thickness of the metal layer located at the fourth edge region to the thickness of the metal layer located at the third edge region is 1.2 to 5.

12. The resonator of any of claims 4-7, wherein a ratio of a length of the metal layer at the first edge region to a length of the metal layer at the second edge region is 1; the ratio of the length of the metal layer positioned in the fourth edge area to the length of the metal layer positioned in the third edge area is 1;

the ratio of the width of the metal layer positioned in the first edge area to the width of the metal layer positioned in the second edge area is 1; the ratio of the width of the metal layer positioned in the fourth edge area to the width of the metal layer positioned in the third edge area is 1;

the ratio of the thickness of the metal layer located in the first edge region to the thickness of the metal layer located in the second edge region is 2; the ratio of the thickness of the metal layer located in the fourth edge region to the thickness of the metal layer located in the third edge region is 2.

13. The resonator of any of claims 3-7, wherein the middle region corresponds to an acoustic speed that is greater than an acoustic speed corresponding to the first edge region and an acoustic speed corresponding to the second edge region, and wherein the acoustic speed corresponding to the first edge region is different than the acoustic speed corresponding to the second edge region;

the sound velocity corresponding to the middle region is greater than the sound velocity corresponding to the third edge region and the sound velocity corresponding to the fourth edge region, and the sound velocity corresponding to the third edge region is different from the sound velocity corresponding to the fourth edge region.

14. The resonator of claim 13, wherein the second edge region corresponds to an acoustic velocity greater than the acoustic velocity corresponding to the first edge region, and wherein the third edge region corresponds to an acoustic velocity greater than the acoustic velocity corresponding to the fourth edge region.

15. The resonator of any of claims 1-7, wherein a width of the metal layer on the first electrode finger is less than or equal to a width of the first electrode finger; the width of the metal layer on the second electrode finger is less than or equal to the width of the second electrode finger.

16. The resonator of any of claims 1-7, wherein a thickness of the metal layer on the first electrode finger is less than a thickness of the first electrode finger; the thickness of the metal layer on the second electrode finger is smaller than that of the second electrode finger.

17. The resonator of any of claims 1-7, wherein the interdigital transducer further comprises a plurality of first dummy fingers and a plurality of second dummy fingers, the first dummy fingers being disposed between the first electrode fingers and the second bus bar, and the first dummy fingers being connected to the second bus bar; the second dummy finger is disposed between the second electrode finger and the first bus bar, and the second dummy finger is connected to the first bus bar.

18. The resonator of any of claims 1-7, further comprising a temperature compensation layer covering the interdigital transducer on the piezoelectric substrate.

19. A resonator comprising a piezoelectric substrate and an interdigital transducer located on the piezoelectric substrate, the interdigital transducer comprising:

the first bus bar and the second bus bar are oppositely arranged;

the sound velocity corresponding to the middle region is respectively greater than the sound velocities corresponding to the at least two fifth edge regions and the sound velocities corresponding to the at least two sixth edge regions;

the sound velocities corresponding to the at least two sixth edge regions sequentially arranged in a direction from the middle region to the second bus bar are sequentially reduced.

20. A filter, characterized in that it comprises at least a plurality of resonators according to any of claims 1-19.

21. An electronic device comprising a substrate and the filter of claim 20 mounted on and electrically connected to the substrate.