Surface acoustic wave resonator and electronic device

Abstract

The invention discloses a surface acoustic wave resonator and an electronic device, which are applied to the technical field of surface acoustic waves, an interdigital transducer comprises two outer-layer bus bars arranged oppositely and at least two inner-layer bus bars arranged oppositely, the inner-layer bus bars are arranged between the outer-layer bus bars, and the outer-layer bus bars and the inner-layer bus bars are both parallel to the length direction; the inner-layer bus bar is provided with a plurality of first protruding parts protruding out of the edge of the inner-layer bus bar in the width direction, the first protruding parts are arranged in the length direction, so that an inner-layer edge sound velocity area is formed on at least one side of the inner-layer bus bar based on the first protruding parts, and an inner-layer sound velocity area is formed on the basis of the inner-layer bus bar; the sound velocity of the inner-layer edge sound velocity area is smaller than that of the inner-layer sound velocity area. The sawtooth structure formed by the plurality of first protruding parts can enable sound waves to generate diffuse reflection during transverse propagation, so that the Q value of a transverse clutter mode is reduced, and the generation of a transverse mode is effectively inhibited.

Description

Technical Field

[0001] The present invention relates to the technical field of surface acoustic wave, and particularly to a surface acoustic wave resonator and an electronic device. Background Art

[0002] Surface Acoustic Wave (SAW) devices are solid devices that utilize the propagation of surface acoustic waves on the surface of piezoelectric materials. Due to their excellent performance, low cost, simple process flow, etc., they have been widely used in the field of wireless communication. In the process of acoustic wave propagation, traditional surface acoustic wave filters will generate transverse modes, which will reduce the Q value of surface acoustic wave devices. Therefore, how to effectively suppress the transverse modes generated during the acoustic wave propagation of surface acoustic wave devices is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0003] The purpose of the present invention is to provide a surface acoustic wave resonator that can effectively suppress the generation of transverse modes; another purpose of the present invention is to provide an electronic device that can effectively suppress the generation of transverse modes.

[0004] To solve the above technical problems, the present invention provides a surface acoustic wave resonator, including:

[0005] A piezoelectric substrate;

[0006] An interdigital transducer disposed on the surface of the piezoelectric substrate;

[0007] The interdigital transducer includes two outer busbars disposed opposite to each other, and at least two inner busbars disposed opposite to each other. The inner busbars are disposed between the outer busbars, and both the outer busbars and the inner busbars are parallel to the length direction;

[0008] The interdigital transducer further includes electrode fingers parallel to each other. The electrode fingers are all parallel to the width direction. The electrode fingers are disposed between the two inner busbars, and the electrode fingers arranged in sequence along the length direction are alternately connected to the inner busbars on both sides;

[0009] The inner busbar is electrically connected to the outer busbar on the same side through a connection structure. The inner busbar is provided with a plurality of first protrusions protruding from the edge of the inner busbar along the width direction. The plurality of first protrusions are arranged along the length direction to form an inner edge sound velocity region based on the first protrusions on at least one side of the inner busbar. An inner sound velocity region is formed based on the inner busbar, and the sound velocity of the inner edge sound velocity region is less than the sound velocity of the inner sound velocity region.

[0010] Optionally, first protrusions are provided on both sides of the inner bus bar, so that a first inner edge sonic velocity region is formed on one side of the inner bus bar, and a second inner edge sonic velocity region is formed on the other side of the inner bus bar. The sonic velocities of the first inner edge sonic velocity region and the second inner edge sonic velocity region are both less than the sonic velocity of the inner sonic velocity region.

[0011] Optionally, the first protrusions are symmetrically arranged on both sides of the inner bus bar.

[0012] Optionally, a first transition sonic velocity region is formed between the inner bus bar and the outer bus bar based on the connection structure, and the sonic velocity of the inner sonic velocity region is less than the sonic velocity of the first transition sonic velocity region.

[0013] Optionally, an outer sonic velocity region is formed based on the outer bus bar, and the sonic velocity of the outer sonic velocity region is less than the sonic velocity of the first transition sonic velocity region.

[0014] Optionally, the electrode finger includes a tail connected to the inner bus bar, and a second transition sonic velocity region is formed based on the tail of the electrode finger. The sonic velocity of the inner sonic velocity region is less than the sonic velocity of the second transition sonic velocity region.

[0015] Optionally, the electrode finger includes a head isolated from the inner bus bar, and a central edge sonic velocity region is formed based on the head of the electrode finger. Second protrusions protruding from the edge of the electrode finger along the length direction are provided on the electrode fingers in the central edge sonic velocity region, and the sonic velocity of the central edge sonic velocity region is less than the sonic velocity of the second transition sonic velocity region.

[0016] Optionally, a central sonic velocity region is formed based on the electrode finger. The central sonic velocity region is located between two central edge sonic velocity regions, and the sonic velocity of the central sonic velocity region is greater than the sonic velocity of the central edge sonic velocity region.

[0017] Optionally, the width of the first protrusion is equal everywhere along the width direction;

[0018] Or, the width of the first protrusion gradually decreases along the direction from the bottom to the top.

[0019] The present application also provides an electronic device including the surface acoustic wave resonator as described in any one of the above.

[0020] A surface acoustic wave resonator provided by the present invention includes: a piezoelectric substrate; an interdigital transducer disposed on the surface of the piezoelectric substrate; the interdigital transducer includes two outer busbars disposed opposite to each other, and at least two inner busbars disposed opposite to each other, the inner busbars are disposed between the outer busbars, and both the outer busbars and the inner busbars are parallel to the length direction; the interdigital transducer further includes electrode fingers parallel to each other, the electrode fingers are all parallel to the width direction, the electrode fingers are disposed between the two inner busbars, and the electrode fingers arranged in sequence along the length direction are alternately connected to the inner busbars on both sides; the inner busbar is electrically connected to the outer busbar on the same side through a connection structure, the inner busbar is provided with a plurality of first protrusions protruding from the edge of the inner busbar in the width direction, the plurality of first protrusions are arranged along the length direction, so as to form an inner edge acoustic velocity region based on the first protrusions on at least one side of the inner busbar, an inner acoustic velocity region is formed based on the inner busbar, and the acoustic velocity of the inner edge acoustic velocity region is less than the acoustic velocity of the inner acoustic velocity region.

[0021] By providing the first protrusions on the inner busbars of the interdigital transducer, and forming the inner edge acoustic velocity region based on the first protrusions, due to the difference in acoustic velocity between the inner edge acoustic velocity region and the inner acoustic velocity region formed by the inner busbars, the sawtooth structure formed by the plurality of first protrusions can cause the acoustic wave to undergo diffuse reflection during lateral propagation, thereby reducing the Q value of the lateral clutter mode and effectively suppressing the generation of the lateral mode.

[0022] The present invention also provides an electronic device, which also has the above beneficial effects and will not be elaborated herein. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a schematic structural diagram of a surface acoustic wave resonator provided by an embodiment of the present invention;

[0025] Figure 2 It is a partial structural diagram of the first surface acoustic wave resonator provided by an embodiment of the present invention;

[0026] Figure 3 It is a partial structural diagram of the second surface acoustic wave resonator provided by an embodiment of the present invention;

[0027] Figure 4 It is a partial structural diagram of the third surface acoustic wave resonator provided by an embodiment of the present invention.

[0028] In the figure: 1. Piezoelectric substrate; 2. Outer layer bus bar; 3. Inner layer bus bar; 31. Inner layer bus bar section; 4. Electrode finger; 5. Connection structure; 6. First protrusion; 7. Second protrusion;

[0029] 10. Inner layer edge sound velocity region; 11. First inner layer edge sound velocity region; 12. Second inner layer edge sound velocity region; 20. Inner layer sound velocity region; 30. First transition sound velocity region; 40. Outer layer sound velocity region; 50. Second transition sound velocity region; 60. Central edge sound velocity region; 70. Central sound velocity region. Detailed implementation mode

[0030] The core of the present invention is to provide a surface acoustic wave resonator. In the prior art, transverse modes will be generated during the propagation of acoustic waves in a surface acoustic wave filter, and this transverse mode will reduce the Q value of the surface acoustic wave device.

[0031] A surface acoustic wave resonator provided by the present invention includes: a piezoelectric substrate; an interdigital transducer disposed on the surface of the piezoelectric substrate; the interdigital transducer includes two relatively arranged outer layer bus bars and at least two relatively arranged inner layer bus bars, the inner layer bus bars are disposed between the outer layer bus bars, and both the outer layer bus bars and the inner layer bus bars are parallel to the length direction; the interdigital transducer further includes parallel electrode fingers, the electrode fingers are all parallel to the width direction, the electrode fingers are disposed between the two inner layer bus bars, and the electrode fingers arranged in sequence along the length direction are alternately connected to the inner layer bus bars on both sides; the inner layer bus bar is electrically connected to the outer layer bus bar on the same side through a connection structure, and the inner layer bus bar is provided with a plurality of first protrusions protruding from the edge of the inner layer bus bar along the width direction, and the plurality of first protrusions are arranged along the length direction to form an inner layer edge sound velocity region based on the first protrusions on at least one side of the inner layer bus bar, an inner layer sound velocity region is formed based on the inner layer bus bar, and the sound velocity of the inner layer edge sound velocity region is less than the sound velocity of the inner layer sound velocity region.

[0032] By providing first protrusions on the inner layer bus bar of the interdigital transducer and forming an inner layer edge sound velocity region based on the first protrusions, due to the difference in sound velocity between the inner layer edge sound velocity region and the inner layer sound velocity region formed by the inner layer bus bar, the sawtooth structure formed by the plurality of first protrusions can cause diffuse reflection of the acoustic wave during transverse propagation, thereby reducing the Q value of the transverse clutter mode and effectively suppressing the generation of transverse modes.

[0033] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation modes. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] Embodiment 1

[0035] Please refer to Figure 1 , Figure 1 , which is a schematic structural diagram of a surface acoustic wave resonator provided by an embodiment of the present invention.

[0036] Refer to Figure 1 , in the embodiment of the present invention, the surface acoustic wave resonator includes: a piezoelectric substrate 1; an interdigital transducer disposed on the surface of the piezoelectric substrate 1; the interdigital transducer includes two outer busbars 2 disposed opposite to each other, and at least two inner busbars 3 disposed opposite to each other, the inner busbars 3 are disposed between the outer busbars 2, and both the outer busbars 2 and the inner busbars 3 are parallel to the length direction; the interdigital transducer further includes electrode fingers 4 parallel to each other, the electrode fingers 4 are all parallel to the width direction, the electrode fingers 4 are disposed between the two inner busbars 3, and the electrode fingers 4 arranged in sequence along the length direction are alternately connected to the inner busbars 3 on both sides; the inner busbars 3 are electrically connected to the outer busbars 2 on the same side through a connection structure 5, and the inner busbars 3 are provided with a plurality of first protrusions 6 protruding from the edge of the inner busbars 3 along the width direction, and the plurality of first protrusions 6 are arranged along the length direction to form an inner edge acoustic velocity region 10 based on the first protrusions 6 on at least one side of the inner busbars 3, and an inner acoustic velocity region 20 is formed based on the inner busbars 3, and the acoustic velocity of the inner edge acoustic velocity region 10 is less than the acoustic velocity of the inner acoustic velocity region 20.

[0037] The above piezoelectric substrate 1 is usually a substrate made of piezoelectric ceramics. The piezoelectric substrate 1 is a key component in the surface acoustic wave resonator that utilizes the propagation characteristics of surface acoustic waves on the material surface to achieve functions such as signal filtering and frequency control. The piezoelectric substrate 1 has sensitive characteristics and can convert extremely weak mechanical vibrations into electrical signals. The specific material of the piezoelectric substrate 1 is not specifically limited in this embodiment, and its specific content can refer to the prior art and will not be elaborated here.

[0038] An interdigital transducer is disposed on the surface of the piezoelectric substrate 1, and its main function is to realize the mutual conversion between electrical signals and surface acoustic waves. Specifically, the interdigital transducer mainly completes this conversion process through the piezoelectric effect and the inverse piezoelectric effect. When an alternating electrical signal is applied to the input end of the interdigital transducer, due to the inverse piezoelectric effect, a periodically distributed electric field will be generated on the surface of the piezoelectric substrate 1. This electric field will cause elastic deformation near the surface of the piezoelectric medium, thereby forming a surface acoustic wave, and the surface acoustic wave will propagate along the surface of the piezoelectric substrate 1.

[0039] For the interdigital transducer, it has a length direction and a width direction. The length direction is the direction in which the interdigital transducer extends, that is, the direction in which the surface acoustic wave propagates; while the width direction is the direction perpendicular to the length direction. In this embodiment, the interdigital transducer has two outer bus bars 2 arranged oppositely, and two inner bus bars 3 arranged oppositely. The inner bus bars 3 are arranged between the outer bus bars 2. That is, in the width direction, the arrangement of these bus bars is: outer bus bar 2 → inner bus bar 3 → inner bus bar 3 → outer bus bar 2. The outer bus bar 2 usually has an input end electrically connected to an external device, and the inner bus bar 3 is electrically connected to the outer bus bar 2 on the same side through a connection structure 5. The above-mentioned outer bus bar 2 and inner bus bar 3 are both parallel to the length direction, that is, parallel to the extending direction of the interdigital transducer, and the outer bus bar 2 and the inner bus bar 3 are parallel to each other.

[0040] The above-mentioned interdigital transducer further includes electrode fingers 4 that are parallel to each other. The electrode fingers 4 are all parallel to the width direction. The electrode fingers 4 are arranged between the two inner bus bars 3. The electrode fingers 4 arranged in sequence along the length direction are alternately connected to the inner bus bars 3 on both sides. The electrode fingers 4 are located in the central area of the interdigital transducer. The electrode fingers 4 usually need to be parallel to each other and also parallel to the width direction, and are arranged alternately in the length direction. In the length direction, the above-mentioned electrode fingers 4 will be alternately connected to the inner bus bars 3 on both sides. That is, if an electrode finger 4 is connected to an inner bus bar 3, its adjacent electrode finger 4 will be connected to another inner bus bar 3. The electrode fingers 4 usually have opposite ends. One end will contact an inner bus bar 3, and the other end will extend to a position adjacent to another inner bus bar 3 but be isolated from another inner bus bar 3.

[0041] In this embodiment, the inner bus bar 3 is provided with a plurality of first protrusions 6 that protrude from the edge of the inner bus bar 3 in the width direction. The plurality of first protrusions 6 are arranged along the length direction. The first protrusion 6 is specifically a structure on the same layer as the inner bus bar 3. The above-mentioned first protrusion 6 is specifically arranged at the edge of the inner bus bar 3, and it will protrude from the contour of the inner bus bar 3 itself in the width direction. That is, a single first protrusion 6 will extend in the width direction, and the plurality of first protrusions 6 will be arranged in the length direction, and there is a gap between adjacent first protrusions 6. Since the first protrusion 6 is specifically arranged at the edge of the inner bus bar 3 and protrudes from the contour of the inner bus bar 3 itself, an inner edge sound velocity region 10 can be formed at the position where the first protrusion 6 is located. The inner edge sound velocity region 10 is formed outside the edge of the inner bus bar 3 and specifically extends along the length direction.

[0042] In this embodiment, an inner acoustic velocity region 20 can be formed based on the position of the inner bus bar 3. The position of the inner acoustic velocity region 20 coincides with the position of the inner bus bar 3 and also extends along the length direction. The above-mentioned inner edge acoustic velocity region 10 and the inner acoustic velocity region 20 are arranged adjacent to each other along the width direction. In this embodiment, the acoustic velocity of the inner edge acoustic velocity region 10 is less than that of the inner acoustic velocity region 20, so as to form a gradient of acoustic velocity in the width direction. And the above-mentioned multiple first protrusions 6 form a serrated structure at the edge of the inner bus bar 3, causing the sound wave to undergo diffuse reflection during transverse propagation, thereby reducing the Q value of the transverse clutter mode and effectively suppressing the generation of the transverse mode.

[0043] In this embodiment, the above-mentioned first protrusion 6 can be an integral structure with the inner bus bar 3, that is, the inner bus bar 3 and the first protrusion 6 can be specifically of the same layer structure, which is convenient for the setting of this structure.

[0044] Specifically, the first protrusions 6 are arranged on both sides of the inner bus bar 3, so as to form a first inner edge acoustic velocity region 11 on one side of the inner bus bar 3 and a second inner edge acoustic velocity region 12 on the other side of the inner bus bar 3. The acoustic velocities of the first inner edge acoustic velocity region 11 and the second inner edge acoustic velocity region 12 are both less than that of the inner acoustic velocity region 20. That is, in this embodiment, the first protrusions 6 can be arranged on both sides of the inner bus bar 3, so that inner edge acoustic velocity regions 10 are formed on both sides of the inner bus bar 3, which are the first inner edge acoustic velocity region 11 and the second inner edge acoustic velocity region 12 respectively. The acoustic velocities of the first inner edge acoustic velocity region 11 and the second inner edge acoustic velocity region 12 both need to be less than that of the inner acoustic velocity region 20, so as to form a structure of low acoustic velocity region → high acoustic velocity region → low acoustic velocity region on one side of the electrode finger 4 in the width direction, so as to further cause the sound wave to undergo diffuse reflection during transverse propagation, thereby reducing the Q value of the transverse clutter mode and effectively suppressing the generation of the transverse mode.

[0045] Generally, the first protrusions 6 are symmetrically arranged on both sides of the inner bus bar 3. That is, for the convenience of preparing the interdigital transducer, in this embodiment, the first protrusions 6 located on both sides of the inner bus bar 3 are symmetrically arranged, that is, the first protrusions 6 located on both sides of the inner bus bar 3 are on the same straight line in the width direction, thereby simplifying the structure of the interdigital transducer, facilitating the preparation of the interdigital transducer, and this structure will not reduce the suppression of the transverse mode by the interdigital transducer.

[0046] A surface acoustic wave resonator provided in this embodiment forms a first protrusion 6 on the inner-layer bus bar 3 of the interdigital transducer, and forms an inner-layer edge sound velocity region 10 based on the first protrusion 6. Based on the difference in sound velocity between the inner-layer edge sound velocity region 10 and the inner-layer sound velocity region 20 formed by the inner-layer bus bar 3, the sawtooth structure formed by multiple first protrusions 6 can cause the acoustic wave to undergo diffuse reflection during transverse propagation, thereby reducing the Q value of the transverse clutter mode and effectively suppressing the generation of the transverse mode.

[0047] Specific details of a surface acoustic wave resonator provided in this application will be introduced in detail in the following invention embodiments.

[0048] Embodiment 2

[0049] Please refer to Figures 2 to 3 , Figure 2 which is a partial structural schematic diagram of the first surface acoustic wave resonator provided in an embodiment of the present invention; Figure 3 which is a partial structural schematic diagram of the second surface acoustic wave resonator provided in an embodiment of the present invention.

[0050] Different from the above embodiment, this embodiment further limits the structure of the interdigital transducer on the basis of the above embodiment. The remaining content has been introduced in detail in the above embodiment and will not be elaborated here.

[0051] See Figure 2 and Figure 3 , in this embodiment, a first transition sound velocity region 30 is formed between the inner-layer bus bar 3 and the outer-layer bus bar 2 based on the connection structure 5, and the sound velocity of the inner-layer sound velocity region 20 is less than the sound velocity of the first transition sound velocity region 30.

[0052] The above connection structure 5 is used to electrically connect the inner-layer bus bar 3 and the outer-layer bus bar 2, and is specifically located between the inner-layer bus bar 3 and the outer-layer bus bar 2. The connection structure 5 may specifically include a connecting wire extending from the inner-layer bus bar 3 to the outer-layer bus bar 2 in the width direction. The specific structure of the connection structure 5 can be set according to the actual situation and will not be specifically limited here. In this embodiment, a first transition sound velocity region 30 can be formed between the inner-layer bus bar 3 and the outer-layer bus bar 2 based on the connection structure 5. The first transition sound velocity region 30 extends in the length direction. If the sound velocity region formed by the first protrusion 6 on the side of the inner-layer bus bar 3 facing the outer-layer bus bar 2 is the first inner-layer edge sound velocity region 11, then the first transition sound velocity region 30 is located between the first inner-layer edge sound velocity region 11 and the outer-layer bus bar 2.

[0053] In this embodiment, it is necessary to control the sound speed in the inner sound speed region 20 to be less than the sound speed in the first transition sound speed region 30, which can be specifically achieved by adjusting the density of the connection lines between the inner bus bar 3 and the outer bus bar 2, and no specific limitation is made here. Obviously, in this embodiment, the sound speed in the first transition sound speed region 30 is greater than the sound speed in the first inner edge sound speed region 11 and also greater than the sound speed in the second inner edge sound speed region 12.

[0054] In this embodiment, an outer sound speed region 40 is formed based on the outer bus bar 2, and the sound speed in the outer sound speed region 40 is less than the sound speed in the first transition sound speed region 30. Similar to the inner sound speed region 20 formed by the inner bus bar 3, the outer sound speed region 40 can be formed based on the position of the outer bus bar 2, and in this embodiment, the sound speed in the outer sound speed region 40 is less than the sound speed in the first transition sound speed region 30. Generally speaking, in this embodiment, the sound speed in the outer sound speed region 40 is approximately equal to the sound speed in the inner sound speed region 20.

[0055] In this embodiment, the electrode finger 4 includes a tail connected to the inner bus bar 3, and a second transition sound speed region 50 is formed based on the tail of the electrode finger 4, and the sound speed in the inner sound speed region 20 is less than the sound speed in the second transition sound speed region 50. The above-mentioned electrode finger 4 includes two opposite ends, where the end connected to one side of the inner bus bar 3 is the tail, and the end isolated from the inner bus bar 3 on the other side is the head. It should be noted that when a first protrusion 6 is provided on the side of the inner bus bar 3 facing the electrode finger 4, the tail of the above-mentioned electrode finger 4 is usually considered to be connected to the first protrusion 6 provided on the side of the inner bus bar 3 facing the electrode finger 4. In the width direction, the tail of the electrode finger 4 is located between the head of the electrode finger 4 and the inner bus bar 3, and when a first protrusion 6 is provided on the side of the inner bus bar 3 facing the electrode finger 4, the tail of the electrode finger 4 is located between the head of the electrode finger 4 and the first protrusion 6.

[0056] In this embodiment, a second transition sound speed region 50 is formed based on the tail of the above-mentioned electrode finger 4, and the second transition sound speed region 50 specifically extends along the length direction. If the sound speed region formed by the first protrusion 6 on the side of the inner bus bar 3 facing the electrode finger 4 is the second inner edge sound speed region 12, then the second transition sound speed region 50 is located on the side away from the inner bus bar 3 of the second inner edge sound speed region 12. In this embodiment, the sound speed in the inner sound speed region 20 needs to be less than the sound speed in the second transition sound speed region 50, and correspondingly, the sound speeds in the first inner edge sound speed region 11 and the second inner edge sound speed region 12 are both less than the sound speed in the second transition sound speed region 50. In this embodiment, the sound speed in the second transition sound speed region 50 is approximately equal to the sound speed in the first transition sound speed region 30.

[0057] In this embodiment, the electrode finger 4 includes a head isolated from the inner layer bus bar 3. A central edge sound velocity region 60 is formed based on the head of the electrode finger 4. The electrode finger 4 within the central edge sound velocity region 60 is provided with a second protrusion 7 protruding from the edge of the electrode finger 4 along the length direction. The sound velocity in the central edge sound velocity region 60 is less than the sound velocity in the second transition sound velocity region 50.

[0058] Specifically, the above-mentioned second protrusion 7 extends along the length direction. The second protrusion 7 is equivalent to increasing the width of the electrode finger 4 in the central edge sound velocity region 60, so that in the length direction, the distance between the electrode fingers 4 provided with the second protrusion 7 is less than the distance between other positions of the electrode fingers 4. In the length direction, the above-mentioned second protrusion 7 can be provided on one side of the electrode finger 4 or on both sides of the electrode finger 4. Usually, in this embodiment, only one second protrusion 7 needs to be provided along the width direction. Of course, the number of the second protrusions 7 in the width direction is not specifically limited in this embodiment and depends on the specific situation. It should be noted that in this embodiment, the electrode fingers 4 will not be connected to each other due to the provision of the above-mentioned second protrusion 7.

[0059] In this embodiment, a central edge sound velocity region 60 can be formed based on the region where the head of the electrode finger 4 is located. The central edge sound velocity region 60 extends along the length direction. In the width direction, the central edge sound velocity region 60 is specifically located on the side of the second transition sound velocity region 50 away from the inner layer bus bar 3. By adjusting the morphology of the second protrusion 7, such as the length of the second protrusion 7 along the length direction, etc., the sound velocity in the central edge sound velocity region 60 is adjusted to be less than the sound velocity in the second transition sound velocity region 50. Usually, the sound velocity in the central edge sound velocity region 60 is not greater than the sound velocity in the first inner layer edge sound velocity region 11 and the sound velocity in the second inner layer edge sound velocity region 12.

[0060] In this embodiment, a central sound velocity region 70 is formed based on the electrode finger 4. The central sound velocity region 70 is located between the two central edge sound velocity regions 60. The sound velocity in the central sound velocity region 70 is greater than the sound velocity in the central edge sound velocity region 60.

[0061] The above-mentioned central sound velocity region 70 is formed based on the middle part of the electrode fingers 4. The central sound velocity region 70 is located between two central edge sound velocity regions 60. Since the second protrusion 7 is provided in the central edge sound velocity region 60, the sound velocity in the central sound velocity region 70 in this embodiment is generally greater than that in the central edge sound velocity region 60, and the sound velocity in the central sound velocity region 70 is generally slightly lower than the sound velocity in the inner layer sound velocity region 20 and the outer layer sound velocity region 40. At this time, on one side of the interdigital transducer provided in this embodiment, in the direction from its center to one side edge along the width direction, the sound velocity is generally medium → low → high → low → medium → low → high → medium, where the "low" sound velocity corresponds to the central edge sound velocity region 60 and the inner layer edge sound velocity region 10, the "medium" sound velocity corresponds to the central sound velocity region 70, the inner layer sound velocity region 20 and the outer layer sound velocity region 40, and the "high" sound velocity corresponds to the first transition sound velocity region 30 and the second transition sound velocity region 50. The gradient directions of any two adjacent sound velocity regions of the sound velocity regions of this structure are opposite along the width direction, which can make the Q value of the clutter mode of the sound wave as low as possible during the transverse transmission process, effectively suppress the generation of the transverse mode, and the above-mentioned multiple different sound velocity regions can effectively suppress different transverse modes during the sound wave transmission.

[0062] Specifically, this embodiment provides two structures of the first protrusion 6. The first one: the width of the first protrusion 6 is equal everywhere along the width direction; the second one: the width of the first protrusion 6 gradually decreases along the direction from the bottom to the top.

[0063] See Figure 2 , the first protrusion 6 of the above-mentioned first structure is specifically rectangular, and the sound velocity of the inner layer edge sound velocity region 10 formed by the first protrusion 6 is equal everywhere along the width direction. And the sound velocity of the inner layer edge sound velocity region 10 is relatively low.

[0064] See Figure 3 , the first protrusion 6 of the above-mentioned second structure is specifically triangular or trapezoidal. The bottom of the first protrusion 6 is the end in contact with the inner layer bus bar 3, and the top of the first protrusion 6 is the end on the side away from the inner layer bus bar 3. In this embodiment, the width of the first protrusion 6 gradually decreases along the direction from the bottom to the top, which can form a triangular or trapezoidal structure. The sound velocity of the inner layer edge sound velocity region 10 formed by the first protrusion 6 of this structure also changes gradually along the direction from the bottom to the top of the first protrusion 6, so that the sound velocity change between the first inner layer edge sound velocity region 11 and the first transition sound velocity region 30 is smoother, and the sound velocity change between the second inner layer edge sound velocity region 12 and the second transition sound velocity region 50 is smoother. This structure can suppress the transverse mode.

[0065] Of course, in this embodiment, the structure of the first protrusion 6 is not specifically limited and depends on the specific situation.

[0066] A surface acoustic wave resonator provided in this embodiment can suppress different transverse modes and improve the Q value of the device by forming acoustic velocity regions with multiple different acoustic velocities at the edge of the interdigital transducer.

[0067] Embodiment 3

[0068] Please refer to Figure 4 , Figure 4 which is a partial structural schematic diagram of the third surface acoustic wave resonator provided by the embodiments of the present invention.

[0069] Different from the above embodiments, in this embodiment, on the basis of the above embodiments, the structure of the inner layer bus bar 3 is further defined. The rest of the content has been introduced in detail in the above embodiments and will not be elaborated here.

[0070] Referring to Figure 4 , in this embodiment, the inner layer bus bar 3 includes a plurality of inner layer bus segments 31 arranged along the length direction, and adjacent inner layer bus segments 31 are separated from each other. Some of the inner layer bus segments 31 are connected to the electrode fingers 4, and the inner layer bus segments 31 connected to the electrode fingers 4 are connected to the outer layer bus bar 2 through the connection structure 5; the first protrusion 6 protrudes along the width direction from the edge of another part of the inner layer bus segments 31. The above inner layer bus segments 31 can form a discontinuous inner layer bus bar 3. At this time, each small segment in the inner layer bus bar 3 can be called an inner layer bus segment 31, and adjacent inner layer bus segments 31 need to be separated from each other, that is, adjacent inner layer bus segments 31 are not connected to each other to form a segmented inner layer bus bar 3. Obviously, the acoustic velocity of the inner acoustic velocity region 20 formed by the segmented inner layer bus bar 3 is usually less than the acoustic velocity of the inner acoustic velocity region 20 formed by the integral inner layer bus bar 3 arranged in a straight line.

[0071] In the half-finger transducer along the width direction in this embodiment, the electrode finger 4 is connected to a part of the inner layer bus bar section 31 but not to all of the inner layer bus bar section 31. Because in this embodiment, the electrode finger 4 needs to be connected to the outer layer bus bar 2 through the inner layer bus bar 3 and the connection structure 5, so the electrode finger 4 needs to be connected to the inner layer bus bar section 31, and the inner layer bus bar section 31 connected to the electrode finger 4 will be connected to the outer layer bus bar 2 through the connection structure 5. Because if the first protrusion 6 is arranged on the same layer for the inner layer bus bar section 31 that connects the electrode finger 4 and the connection structure 5 at the same time, the structure of the first protrusion 6 will not be obvious due to the coincidence with the structure connected to the electrode finger 4 and the above connection structure 5. In order to make the function of the first protrusion 6 more obvious, the electrode finger 4 only needs to be connected to a part of the inner layer bus bar section 31. Correspondingly, the first protrusion 6 also needs to protrude along the width direction from the edge of the other part of the inner layer bus bar section 31, that is, at least part of the inner layer bus bar section 31 not connected to the electrode finger 4 can be provided with the above first protrusion 6.

[0072] Generally, the first protrusion 6 is arranged on at least one side along the width direction of the inner layer bus bar section 31 not connected to the electrode finger 4. More specifically, the first protrusion 6 is arranged on both sides of the inner layer bus bar section 31 not connected to the electrode finger 4 to form an inner layer edge sound velocity region 10 on both sides of the inner layer sound velocity region 20. That is, in this embodiment, the first protrusion 6 can be arranged on the edge of the inner layer bus bar section 31 not connected to the electrode finger 4 in part, and usually on the edge of all the inner layer bus bar sections 31 not connected to the electrode finger 4. Of course, the above protrusion can also be arranged on the inner layer bus bar section 31 connected to the electrode finger 4, which is not specifically limited here.

[0073] In this embodiment, the number of the inner layer bus bar sections 31 forming an inner layer bus bar 3 is at least not less than half of the number of the electrode fingers 4, because only half of the electrode fingers 4 in the half-finger transducer need to be connected to the inner layer bus bar section 31 on one side. In order to ensure that there is an inner layer bus bar section 31 not connected to the electrode finger 4, the number of the inner layer bus bar sections 31 forming an inner layer bus bar 3 needs to be at least not less than half of the number of the electrode fingers 4. Generally, in this embodiment, the number of the inner layer bus bar sections 31 forming an inner layer bus bar 3 is equal to the number of the electrode fingers 4, and the inner layer bus bar sections 31 are arranged corresponding to the electrode fingers 4. At this time, the electrode finger 4 is connected to the corresponding inner layer bus bar section 31, and the inner layer bus bar sections 31 connected to the electrode finger 4 and the inner layer bus bar sections 31 not connected to the electrode finger 4 are specifically arranged alternately along the length direction. In other words, the inner layer bus bar sections 31 provided with the first protrusion 6 in this embodiment can be arranged alternately with the inner layer bus bar sections 31 not provided with the first protrusion 6. In this embodiment, the specific morphology of the first protrusion 6 is not specifically limited and depends on the specific situation.

[0074] A surface acoustic wave resonator provided in this embodiment can suppress different transverse modes and improve the Q value of the device by forming sonic velocity regions with various sonic velocities at the edge of the interdigital transducer.

[0075] Embodiment 4

[0076] The following introduces an electronic device provided in an embodiment of the present invention. The electronic device described below can be correspondingly referred to the surface acoustic wave resonator described above.

[0077] In this embodiment, the electronic device includes a surface acoustic wave resonator provided in any of the above-described embodiments of the invention. The specific structure of the surface acoustic wave resonator has been described in detail in the above-described embodiments of the invention and will not be elaborated here. For the remaining structures of the electronic device, such as the antenna, the housing, etc., reference can be made to the prior art and will not be elaborated here.

[0078] Since the electronic device provided in this embodiment specifically uses the surface acoustic wave resonator provided in the above embodiment, the electronic device can effectively suppress the generation of transverse modes and thus has a higher Q value.

[0079] Finally, it should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the existence of additional identical elements in the process, method, article or device including the element.

[0080] The above has introduced in detail a surface acoustic wave resonator and an electronic device provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A surface acoustic wave resonator, characterized in that, Comprising: A piezoelectric substrate; An interdigital transducer disposed on the surface of the piezoelectric substrate; The interdigital transducer includes two outer busbars disposed opposite to each other, and at least two inner busbars disposed opposite to each other. The inner busbars are disposed between the outer busbars, and both the outer busbars and the inner busbars are parallel to the length direction; The interdigital transducer further includes electrode fingers parallel to each other. The electrode fingers are all parallel to the width direction. The electrode fingers are disposed between the two inner busbars, and the electrode fingers arranged in sequence along the length direction are alternately connected to the inner busbars on both sides; The inner busbar is electrically connected to the outer busbar on the same side through a connection structure. The inner busbar is provided with a plurality of first protrusions protruding from the edge of the inner busbar along the width direction. The plurality of first protrusions are arranged along the length direction to form an inner edge acoustic velocity region based on the first protrusions on at least one side of the inner busbar. An inner acoustic velocity region is formed based on the inner busbar, and the acoustic velocity of the inner edge acoustic velocity region is less than the acoustic velocity of the inner acoustic velocity region.

2. The surface acoustic wave resonator according to claim 1, characterized in that, Both sides of the inner busbar are provided with the first protrusions to form a first inner edge acoustic velocity region on one side of the inner busbar and a second inner edge acoustic velocity region on the other side of the inner busbar. The acoustic velocities of the first inner edge acoustic velocity region and the second inner edge acoustic velocity region are both less than the acoustic velocity of the inner acoustic velocity region.

3. The surface acoustic wave resonator according to claim 2, wherein The first protrusions are symmetrically arranged on both sides of the inner busbar.

4. The surface acoustic wave resonator according to claim 1, wherein A first transition acoustic velocity region is formed between the inner busbar and the outer busbar based on the connection structure, and the acoustic velocity of the inner acoustic velocity region is less than the acoustic velocity of the first transition acoustic velocity region.

5. The surface acoustic wave resonator according to claim 4, characterized in that, An outer acoustic velocity region is formed based on the outer busbar, and the acoustic velocity of the outer acoustic velocity region is less than the acoustic velocity of the first transition acoustic velocity region.

6. The surface acoustic wave resonator according to claim 1, wherein, The electrode finger includes a tail connected to the inner busbar. A second transition acoustic velocity region is formed based on the tail of the electrode finger, and the acoustic velocity of the inner acoustic velocity region is less than the acoustic velocity of the second transition acoustic velocity region.

7. The surface acoustic wave resonator according to claim 6, characterized in that, The electrode finger includes a head isolated from the inner busbar. A central edge acoustic velocity region is formed based on the head of the electrode finger. The electrode fingers in the central edge acoustic velocity region are provided with second protrusions protruding from the edge of the electrode finger along the length direction, and the acoustic velocity of the central edge acoustic velocity region is less than the acoustic velocity of the second transition acoustic velocity region.

8. The surface acoustic wave resonator according to claim 7, wherein A central acoustic velocity region is formed based on the electrode finger. The central acoustic velocity region is located between the two central edge acoustic velocity regions, and the acoustic velocity of the central acoustic velocity region is greater than the acoustic velocity of the central edge acoustic velocity region.

9. The surface acoustic wave resonator according to claim 1, characterized in that, The width of the first protrusion is equal everywhere along the width direction; Or, the width of the first protrusion gradually decreases along the direction from the bottom to the top.

10. An electronic device, characterized in that, Comprising a surface acoustic wave resonator according to any one of claims 1 to 9.

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