Surface acoustic wave device, filter and radio frequency front-end module

Abstract

Provided in the present application are a surface acoustic wave device, a filter and a radio frequency front-end module. The surface acoustic wave device comprises a piezoelectric substrate and an interdigital transducer, wherein the interdigital transducer comprises busbars and electrode units; each electrode structure comprises a connecting portion, a conductive portion and at least two finger portions; each connecting portion comprises a connecting strip; and the finger portions of each electrode structure are connected to the corresponding conductive portion. The number of connecting strips is less than that of finger portions, thus reducing or avoiding the impact of spurious modes on the performance of the surface acoustic wave device.

Description

Surface acoustic wave device, filter and radio frequency front-end module TECHNICAL FIELD

[0001] The present application relates to the technical field of communication, in particular to a surface acoustic wave device, a filter and a radio frequency front-end module. BACKGROUND

[0002] A surface acoustic wave device processes an acoustic signal propagating on a surface of a material with piezoelectric characteristics by using the characteristics of an acoustic-electric transducer. The surface acoustic wave device has the advantages of low cost, small size and multiple functions, and thus is widely used in the fields of radar, communication, navigation and identification. The surface acoustic wave device includes an interdigital transducer (IDT) which can convert an electric signal into an acoustic signal or convert an acoustic signal into an electric signal. When the surface acoustic wave device is working, in addition to the transverse dispersion generated in the aperture direction, there is also dispersion mode in the gap area formed between the bus bar and the plurality of electrode fingers, which is referred to as a miscellaneous mode. The existence of the miscellaneous mode has a great impact on the performance of the surface acoustic wave device. SUMMARY

[0003] The present application provides a surface acoustic wave device, a filter and a radio frequency front-end module, which aims to reduce or avoid the impact of miscellaneous mode on the performance of the surface acoustic wave device.

[0004] The present application provides a surface acoustic wave device, which comprises a piezoelectric substrate and an interdigital transducer, and the interdigital transducer is arranged on the piezoelectric substrate. The interdigital transducer comprises:

[0005] Two bus bars, the two bus bars are arranged opposite to each other along a first direction;

[0006] An electrode unit, which comprises two electrode structures, and the two electrode structures are arranged between the two bus bars. Each of the two electrode structures is connected to one of the bus bars. The electrode structure comprises a connecting part, a conductive part and at least two finger parts. The connecting part comprises a connecting strip, the bus bar is connected to the conductive part through the connecting strip, and the finger part of the electrode structure is connected to the conductive part. Each of the finger parts is arranged in a second direction perpendicular to the first direction. In the first direction, the connecting part and the conductive part are arranged in a non-crossing area between the two bus bars. In the second direction, the crossing area is an area where the finger parts overlap with each other;

[0007] The number of the connection strips is less than the number of the finger strip parts in the same electrode structure; the non-crossing area includes a first gap area, which is an area between the bus bar and the conductive part; an area in which a finger end of at least one finger strip part of the electrode structure extends towards the bus bar connected to another electrode structure along the first direction is a first area; an area in the non-crossing area except the first gap area is a second area; and an area in which the first area and the second area overlap with each other is a preset area; and no conductive structure is arranged in the preset area.

[0008] The application further provides a surface acoustic wave device, which comprises a piezoelectric substrate and an interdigital transducer arranged on the piezoelectric substrate; the interdigital transducer comprises:

[0009] Two bus bars, the two bus bars are oppositely arranged along a first direction;

[0010] An electrode unit, which comprises two electrode structures arranged between the two bus bars; each of the two electrode structures is connected to one of the bus bars; each of the electrode structures comprises a connection part, a conductive part and at least two finger strip parts; the connection part comprises a connection strip, the bus bar is connected to the conductive part through the connection strip, and the finger strip part of the electrode structure is connected to the conductive part; each of the finger strip parts is arranged along a second direction perpendicular to the first direction; in the first direction, the two bus bars have a crossing area and a non-crossing area, and the connection part and the conductive part are arranged in the non-crossing area; in the second direction, the crossing area is an area in which the finger strip parts overlap with each other;

[0011] The number of the connection strips is less than the number of the finger strip parts in the same electrode structure; in the first direction, a finger end of at least one finger strip part of the electrode structure is not provided with a conductive structure within a preset distance from the finger end, and the preset distance is less than or equal to 0.8λ, and λ is a wavelength of the surface acoustic wave device.

[0012] The application further provides a surface acoustic wave device, which comprises a piezoelectric substrate and an interdigital transducer arranged on the piezoelectric substrate; the interdigital transducer comprises:

[0013] Two bus bars, the two bus bars are oppositely arranged along a first direction;

[0014] The electrode unit comprises two electrode structures, the two electrode structures are arranged between the two bus bars, each of the two electrode structures is connected to one of the bus bars, the electrode structure comprises a connecting part, a conductive part and at least two finger parts, the connecting part comprises a connecting strip, the bus bar is connected to the conductive part through the connecting strip, and the finger part of the electrode structure is connected to the conductive part; each of the finger parts is arranged in a second direction perpendicular to the first direction; in the first direction, the two bus bars have a crossing area and a non-crossing area, and the connecting part and the conductive part are arranged in the non-crossing area; in the second direction, the crossing area is an area in which the finger parts overlap each other.

[0015] In one of the electrode structures, the number of the connecting strips is less than the number of the finger parts; the finger parts of the two electrode structures are respectively first finger parts and second finger parts, one of the electrode structures comprises a first sub-unit, and the other electrode structure comprises a second sub-unit, the first sub-unit and the second sub-unit are alternately arranged in the second direction; the first sub-unit comprises at least two adjacent first finger parts, and the second sub-unit comprises at least two adjacent second finger parts.

[0016] The application further provides a surface acoustic wave device, comprising a piezoelectric substrate and an interdigital transducer arranged on the piezoelectric substrate; the interdigital transducer comprises:

[0017] The two bus bars are arranged opposite to each other in a first direction.

[0018] The electrode unit comprises two electrode structures, the two electrode structures are arranged between the two bus bars, each of the two electrode structures is connected to one of the bus bars, the electrode structure comprises a connecting part, a conductive part and at least two finger parts, the connecting part comprises a connecting strip, the bus bar is connected to the conductive part through the connecting strip, and the finger part of the electrode structure is connected to the conductive part; each of the finger parts is arranged in a second direction perpendicular to the first direction; in the first direction, the two bus bars have a crossing area and a non-crossing area, and the connecting part and the conductive part are arranged in the non-crossing area; in the second direction, the crossing area is an area in which the finger parts overlap each other.

[0019] In one of the electrode structures, the number of the connecting strips is less than the number of the finger parts, and the ratio of the number of the finger parts to the number of the connecting strips is A, A is greater than 1 and less than or equal to 8.

[0020] The application further provides a filter comprising the surface acoustic wave device.

[0021] The embodiment of the present application further provides a radio frequency front-end module, comprising the surface acoustic wave device described in any of the above.

[0022] The surface acoustic wave device, the filter and the radio frequency front-end module provided by the present application can change the original periodicity of the finger strip part by connecting at least two finger strip parts through the conductive part, thereby weakening the spurious mode; and the number of the connecting strips in the same electrode structure is less than the number of the finger strip parts, that is, at least two finger strip parts connected together are connected to the bus bar through less connecting strips, which can reduce the possibility of generating an equivalent resonant cavity in the non-crossing area, thereby reducing the possibility of spurious mode excitation, and as much as possible reducing or avoiding the probability of the acoustic wave energy in the crossing area being excited to leak to the non-crossing area, and further realizing the suppression of the spurious mode, thereby reducing or avoiding the influence of the spurious mode on the performance of the surface acoustic wave device.

[0023] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the disclosure of the embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0025] FIG. 1 is a structural schematic diagram of a surface acoustic wave device in the related art;

[0026] FIG. 2 is a structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0027] FIG. 3 is a structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0028] FIG. 4 is a structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0029] FIG. 5 is a structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0030] FIG. 6 is a structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0031] FIG. 7 is a structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0032] FIG. 8 is a comparison diagram of admittance curves of the surface acoustic wave devices in the related art and the present embodiment;

[0033] FIG. 9 is a comparison diagram of admittance curves of the surface acoustic wave devices in the related art and the present embodiment;

[0034] Fig. 10 is a comparison chart of admittance curves of the surface acoustic wave device of the related art and the present embodiment;

[0035] Fig. 11 is a comparison chart of Q values of the surface acoustic wave device of the related art and the present embodiment.

[0036] BRIEF DESCRIPTION OF DRAWINGS 1000, surface acoustic wave device; 100, piezoelectric substrate; 101, substrate; 102, piezoelectric thin film; 200, interdigital transducer; 10, bus bar; 11, first bus bar; 12, second bus bar; 20, electrode unit; 21, electrode structure; 21a, first electrode structure; 21b, second electrode structure; 21c, first subunit; 21d, second subunit; 211, connecting portion; 2111, connecting strip; 2111a, first connecting strip; 2111b, second connecting strip; 212, conductive portion; 2121, first conductive portion; 2122, second conductive portion; 213, finger portion; 2131, first finger portion; 2132, second finger portion; 214, dummy finger; 2141, first dummy finger; 2142, second dummy finger; 30, dielectric layer; 40, low acoustic velocity portion; 300, reflection structure; A1, crossing region; A11, intermediate region; A12, edge region; B1, non-crossing region; B11, first gap region; B12, second gap region; C1, first region; C2, second region; C3, preset region. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0038] It should also be understood that the terms used in the present application are only for the purpose of describing particular embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, unless otherwise clearly indicated by the context, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0039] It should be further understood that the term "and / or" used in the present application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0040] Referring to FIG. 1, a surface acoustic wave device 1000 in the related art generally includes a piezoelectric substrate 100 and an interdigital transducer 200 disposed on the piezoelectric substrate 100. The interdigital transducer 200, in cooperation with the piezoelectric substrate 100, can convert an electrical signal into an acoustic wave or convert an acoustic wave into an electrical signal. The surface acoustic wave device 1000 can also include a reflective structure 300, which can be disposed on opposite sides of the interdigital transducer 200, specifically, on opposite sides of the interdigital transducer 200 in the direction of propagation of the acoustic wave. The reflective structure 300 is configured to reflect the acoustic wave and confine the acoustic wave to the region of the interdigital transducer 200.

[0041] Some embodiments of the present application will be described in detail below with reference to the drawings. The following examples and features in the examples can be combined with each other without conflict.

[0042] In some embodiments of the present application, the surface acoustic wave device 1000 can include a surface acoustic wave resonator. The surface acoustic wave resonator can be a normal surface acoustic wave resonator (Normal-SAW), a temperature compensated surface acoustic wave resonator (TC-SAW), a surface acoustic wave resonator with a multi-layer substrate structure, a transversely excited film bulk acoustic resonator, or the like.

[0043] In some embodiments, the piezoelectric substrate 100 can be made of at least one of quartz, aluminum nitride, sapphire, LN (lithium niobate, LiNbO3), LT (lithium tantalate, LiTaO3), or the like, which is not limited in the present application.

[0044] Referring to FIG. 2, in some embodiments, the piezoelectric substrate 100 includes a piezoelectric film 102 and a substrate 101 stacked together, and the interdigital transducer 200 is disposed on a surface of the piezoelectric film 102 facing away from the substrate 101. In this way, the Q value of the surface acoustic wave device 1000 can be improved, and the surface acoustic wave device 1000 can be applied to a higher frequency band of 5G and above. The substrate 101 can be made of silicon, for example.

[0045] In some embodiments, the interdigital transducer 200 can be made of a single metal material or a composite or alloy of different metals. Optionally, the interdigital transducer 200 can be made of one of aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, or a composite or alloy of the above metals.

[0046] Referring to FIG. 3, in some embodiments, the interdigital transducer 200 includes bus bars 10 and electrode units 20, the number of bus bars 10 includes two, the two bus bars 10 are arranged opposite to each other along a first direction; the electrode unit 20 includes two electrode structures 21, the two electrode structures 21 are arranged between the two bus bars 10; each electrode structure 21 is connected with one bus bar 10; the electrode structure 21 includes a connecting part 211, a conductive part 212 and at least two finger parts 213, the connecting part 211 includes a connecting strip 2111, the bus bar 10 is connected with the conductive part 212 through the connecting strip 2111, the finger part 213 of the electrode structure 21 is connected with the conductive part 212; each finger part 213 is arranged in a second direction perpendicular to the first direction; in the first direction, the two bus bars 10 have a crossing area A1 and a non-crossing area B1, the connecting part 211 and the conductive part 212 are arranged in the non-crossing area B1; in the second direction, the crossing area A1 is an area in which each finger part 213 overlaps with each other. In the same electrode structure 21, the number of connecting strips 2111 is less than the number of finger parts 213; the non-crossing area B1 includes a first gap area B11, the first gap area B11 is an area between the bus bar 10 and the conductive part 212, the area in which the finger end of at least one finger part 213 of the electrode structure 21 extends along the first direction towards the bus bar 10 connected with the other electrode structure 21 is defined as a first area C1, the area in the non-crossing area B1 except the first gap area B11 is a second area C2, the area in which the first area C1 and the second area C2 overlap with each other is a preset area C3; no conductive structure is arranged in the preset area C3.

[0047] The surface acoustic wave device 1000 of the above embodiment can change the original periodicity of the finger part 213 by connecting the at least two finger parts 213 through the conductive part 212, so as to weaken the spurious mode; and since the number of connecting strips 2111 is less than the number of finger parts 213 in the same electrode structure 21, that is, the at least two finger parts 213 connected together are connected to the bus bar 10 through less connecting strips 2111, the possibility of generating an equivalent resonant cavity in the non-crossing area B1 can be reduced, so as to reduce the possibility of spurious mode vibration, to reduce or avoid as much as possible the probability that the acoustic wave energy leaked from the crossing area A1 is excited in the non-crossing area B1, and to realize the suppression of the spurious mode, so as to reduce or avoid the influence of the spurious mode on the performance of the surface acoustic wave device 1000. In addition, since no conductive structure is arranged in the preset area C3 in which the first area C1 and the second area C2 overlap with each other, compared with the case that a conductive structure is arranged in the preset area C3, the embodiment of the present application can effectively suppress the spurious mode on the high frequency side of the anti-resonance point, improve the spurious mode suppression effect, is simple to process, and is conducive to saving the use of conductive material, so as to be conducive to realizing the light weight and reducing the cost of the product.

[0048] Exemplarily, the conductive structure, i.e. the structure with conductive performance, refers to the structure made of material with conductive performance, such as metal. The structure without conductive performance at least includes the structure made of at least one of the following materials: the material used for preparing the interdigital transducer 200, the material used for preparing the conductive part 212, the material used for preparing the finger part 213, the material used for preparing the bus bar 10, and other any suitable conductive material.

[0049] Referring to FIG. 3, exemplarily, the non-crossing area B1 includes a first gap area B11 and a second gap area B12. The first gap area B11 is the area between the bus bar 10 and the conductive part 212, and the second gap area B12 is the area between the crossing area A1 and the conductive part 212. In the first direction, the two bus bars 10 have the crossing area A1 therebetween, and the crossing area A1 includes a middle area A11 and edge areas A12 on both sides of the middle area A11.

[0050] Referring to FIG. 4, exemplarily, the two bus bars 10 are a first bus bar 11 and a second bus bar 12, which are arranged in the first direction and spaced apart from each other on the piezoelectric substrate 100. The two electrode structures 21 are a first electrode structure 21a and a second electrode structure 21b. The finger part 213 of the first electrode structure 21a is a first finger part 2131, the conductive part 212 of the first electrode structure 21a is a first conductive part 2121, and the connecting part 211 of the first electrode structure 21a includes a first connecting strip 2111a. The finger part 213 of the second electrode structure 21b is a second finger part 2132, the conductive part 212 of the second electrode structure 21b is a second conductive part 2122, and the connecting part 211 of the second electrode structure 21b includes a second connecting strip 2111b. The first bus bar 11 is connected to the first conductive part 2121 through the first connecting strip 2111a, and the first conductive part 2121 is connected to at least two first finger parts 2131. In the first electrode structure 21a, the number of the first connecting strips 2111a is less than the number of the first finger parts 2131. The second bus bar 12 is connected to the second conductive part 2122 through the second connecting strip 2111b, and the second conductive part 2122 is connected to at least two second finger parts 2132. In the second electrode structure 21b, the number of the second connecting strips 2111b is less than the number of the second finger parts 2132. The first finger parts 2131 and the second finger parts 2132 are arranged in the second direction perpendicular to the first direction. Exemplarily, the first direction is perpendicular to the second direction in the plane of the piezoelectric substrate 100. Exemplarily, the first direction is the arrangement direction of the two bus bars 10 or the length extension direction of the finger part 213, and the second direction is the sound wave propagation direction or the arrangement direction of each finger part 213. Exemplarily, the first direction is shown as the X direction in FIG. 3, and the second direction is shown as the Y direction in FIG. 3.

[0051] Referring to FIG. 4, for example, two electrode structures 21 are arranged between the first bus bar 11 and the second bus bar 12; in the first direction, one end of the first connecting strip 2111a is connected to the first bus bar 11, the other end of the first connecting strip 2111a is connected to the first conductive part 2121, one end of the first finger strip 2131 is connected to the first conductive part 2121, the other end of the first finger strip 2131 is spaced apart from the second conductive part 2122, and the other end of the first finger strip 2131 is spaced apart from the second bus bar 12; in the first direction, one end of the second connecting strip 2111b is connected to the second bus bar 12, the other end of the second connecting strip 2111b is connected to the second conductive part 2122, one end of the second finger strip 2132 is connected to the second conductive part 2122, the other end of the second finger strip 2132 is spaced apart from the first conductive part 2121, and the other end of the second finger strip 2132 is spaced apart from the first bus bar 11. Understandably, the end of each first finger strip 2131 close to the second bus bar 12 can be flush or not flush, and the end of each second finger strip 2132 close to the first bus bar 11 can be flush or not flush. In the second direction, the widths of the finger strips 213 can be the same or different.

[0052] Referring to FIG. 4, the intersection area A1 and the non-intersection area B1 located at both ends of the intersection area A1 in the first direction are formed between the two bus bars 10. Understandably, the area between the first finger strip 2131 and the second bus bar 12 is one of the non-intersection areas B1, and the area between the second finger strip 2132 and the first bus bar 11 is the other non-intersection area B1.

[0053] In the same non-intersection area B1, the number of preset areas C3 can include one, two, three or more. For example, referring to FIG. 3, the tip of one finger strip 213 in the same electrode structure 21 is formed with a preset area C3, and the number of preset areas C3 is one. For example, the tip of each of at least two finger strips 213 in the same electrode structure 21 is formed with a preset area C3, and the number of preset areas C3 is at least two. For example, referring to FIG. 4, in the second electrode structure 21b, the tip of the second finger strip 2132a is formed with a preset area C3, and the tip of the second finger strip 2132b is formed with another preset area C3, and the number of preset areas C3 is two. In some cases, in the same electrode structure 21, each finger strip 213 formed with a preset area C3 can share one preset area C3; or, in the same electrode structure 21, the tip of each of at least two finger strips 213 is formed with a preset area C3, and adjacent preset areas C3 can be connected or not connected.

[0054] Referring to FIG. 4, for example, the at least one second finger portion 2132 of the second electrode structure 21b includes a second finger portion 2132a and a second finger portion 2132b, a region where a tip of the second finger portion 2132a or a tip of the second finger portion 2132b extends in the first direction toward the first bus bar 11 is defined as a first region C1, a region other than the first gap region B11 in the non-crossing region B1 is defined as a second region C2, and a region where the first region C1 and the second region C2 overlap with each other is defined as a preset region C3, and no conductive structure is provided in the preset region C3. The at least one first finger portion 2131 of the first electrode structure 21a includes a first finger portion 2131a and a first finger portion 2131b, a region where a tip of the first finger portion 2131a or a tip of the first finger portion 2131b extends in the first direction toward the second bus bar 12 is defined as the first region C1, the region other than the first gap region B11 in the non-crossing region B1 is defined as the second region C2, and a region where the first region C1 and the second region C2 overlap with each other is defined as the preset region C3, and no conductive structure is provided in the preset region C3.

[0055] In some embodiments, a dimension of the preset region C3 in the first direction is less than or equal to 0.8λ, and λ is a wavelength of the surface acoustic wave device 1000. In this way, the mass at the preset region C3 is reduced, the sound velocity of the preset region C3 is increased, the spurious mode on the high frequency side of the anti-resonance point is suppressed, and the spurious mode suppression effect is improved.

[0056] Referring to FIG. 4, in some embodiments, in the same electrode unit 20, the finger portions 213 of one electrode structure 21 and the finger portions 213 of another electrode structure 21 are arranged alternately and spaced apart. For example, in the same electrode unit 20, the first finger portion 2131 and the second finger portion 2132 are arranged alternately and spaced apart in the second direction, so as to improve the excitation coefficient of the surface acoustic wave device 1000 and effectively excite resonance.

[0057] In other embodiments, the first finger portion 2131 and the second finger portion 2132 can also be arranged in other suitable manners. Referring to FIG. 5, in some embodiments, the finger portions 213 of the two electrode structures 21 are respectively the first finger portion 2131 and the second finger portion 2132; one of the electrode structures 21 includes the first sub-unit 21c, and the other electrode structure 21 includes the second sub-unit 21d, the first sub-unit 21c and the second sub-unit 21d are arranged alternately and spaced apart along the second direction; the first sub-unit 21c includes at least two adjacent first finger portions 2131, and the second sub-unit 21d includes at least two adjacent second finger portions 2132. Such a structure can improve the Q value of the surface acoustic wave device 1000 and can be applied to higher frequency bands such as 5G and above. For example, the first electrode structure 21a includes the first sub-unit 21c, and the first sub-unit 21c includes at least two adjacent first finger portions 2131; the second electrode structure 21b includes the second sub-unit 21d, and the second sub-unit 21d includes at least two adjacent second finger portions 2132. The number of the first sub-unit 21c and the second sub-unit 21d can be one, two or more. For example, the number of the first finger portion 2131 is two, the number of the first sub-unit 21c is one, and the two first finger portions 2131 form a first sub-unit 21c; the number of the second finger portion 2132 is two, the number of the second sub-unit 21d is one, and the two second finger portions 2132 form a second sub-unit 21d. For another example, the number of the first finger portion 2131 is three, the number of the first sub-unit 21c is one, and the three first finger portions 2131 form a first sub-unit 21c; the number of the second finger portion 2132 is three, the number of the second sub-unit 21d is one, and the three second finger portions 2132 form a second sub-unit 21d. When the first sub-unit 21c is multiple, the number of the first finger portion 2131 included in each first sub-unit 21c can be the same or different; when the second sub-unit 21d is multiple, the number of the second finger portion 2132 included in each second sub-unit 21d can be the same or different.

[0058] Referring to FIG. 5, for example, the number of the first finger portions 2131 and the second finger portions 2132 is even, the number of the first finger portions 2131 of the first sub-units 21c is the same as the number of the second finger portions 2132 of the second sub-units 21d, all the first finger portions 2131 form at least two first sub-units 21c, the number of the first finger portions 2131 of each first sub-unit 21c is the same; all the second finger portions 2132 form at least two second sub-units 21d, the number of the second finger portions 2132 of each second sub-unit 21d is the same. In this way, the resonance can be excited more effectively, and the Q value of the surface acoustic wave device 1000 can be improved more effectively. For example, all the first finger portions 2131 form two first sub-units 21c, one of which includes the first finger portion 2131a and the first finger portion 2131b adjacent to each other, and the other of which includes the first finger portion 2131c and the first finger portion 2131d adjacent to each other; all the second finger portions 2132 form two second sub-units 21d, one of which includes the second finger portion 2132a and the second finger portion 2132b adjacent to each other, and the other of which includes the second finger portion 2132c and the second finger portion 2132d adjacent to each other; the first sub-units 21c and the second sub-units 21d are arranged alternately and spaced apart in the second direction. For example, referring to FIG. 5, the number of the first finger portions 2131 is four, the number of the first sub-units 21c is two, two first finger portions 2131 adjacent to each other form one first sub-unit 21c; the number of the second finger portions 2132 is four, the number of the second sub-units 21d is two, two second finger portions 2132 form one second sub-unit 21d, and two first sub-units 21c and two second sub-units 21d are arranged alternately and spaced apart in the second direction. For another example, the number of the first finger portions 2131 is six, the number of the first sub-units 21c is three, two first finger portions 2131 adjacent to each other form one first sub-unit 21c; the number of the second finger portions 2132 is six, the number of the second sub-units 21d is three, two second finger portions 2132 form one second sub-unit 21d; and three first sub-units 21c and three second sub-units 21d are arranged alternately and spaced apart in the second direction. For another example, the number of the first finger portions 2131 is six, the number of the first sub-units 21c is two, three first finger portions 2131 adjacent to each other form one first sub-unit 21c; the number of the second finger portions 2132 is six, the number of the second sub-units 21d is two, three second finger portions 2132 form one second sub-unit 21d; and two first sub-units 21c and two second sub-units 21d are arranged alternately and spaced apart in the second direction.

[0059] In some embodiments, all of the first finger portions 2131 can form one or at least two first sub-units 21c, and all of the second finger portions 2132 can form one or at least two second sub-units 21d. In other embodiments, the remaining first finger portions 2131 and the remaining second finger portions 2132 are alternately and spacedly arranged in addition to the first finger portions 2131 of the first sub-unit 21c and the second finger portions 2132 of the second sub-unit 21d.

[0060] In some embodiments, the ratio of the number of the finger portions 213 to the number of the connecting portions 2111 in the same electrode structure 21 is A, A is greater than 1 and less than or equal to 8, such as A is 2, 3, 4, 5, 6, 7, 8 or any other suitable value between 1 and 8. A that is too small can cause the current of the first gap region B11 to be too large, and the SAW device 1000 can be easily burned out. A that is too large can cause the connecting portions 211 to be too long, and the SAW device 1000 can be easily burned out. A within the range can effectively reduce the possibility of generating an equivalent resonant cavity in the non-crossing region B1, thereby effectively reducing the possibility of the excitation of the spurious mode, and avoiding the sound wave energy leaked from the crossing region A1 to the non-crossing region B1 to be excited as much as possible, and thereby effectively achieving the suppression of the spurious mode. A within the range can effectively reduce the mass of the connecting portions 211, and can also make the connecting portions 211 and the finger portions 213 have suitable equivalent resistances, and make the SAW device 1000 more reliable, and effectively reduce the problem that the SAW device 1000 is easily burned out due to the current of the first gap region B11 being too large or the connecting portions 211 being too long.

[0061] Please refer to FIG. 4. In some embodiments, the number of the connecting portions 2111 in the same electrode structure 21 is one. This can as much as possible reduce the possibility of generating an equivalent resonant cavity in the non-crossing region B1, thereby as much as possible reducing the possibility of the excitation of the spurious mode, and avoiding the sound wave energy leaked from the crossing region A1 to the non-crossing region B1 to be excited to the maximum extent, and thereby achieving the suppression of the spurious mode to the maximum extent. The number of the connecting portions 2111 being one can as much as possible reduce the mass of the connecting portions 211, and can also make the connecting portions 211 and the finger portions 213 have suitable equivalent resistances, and make the SAW device 1000 more reliable, and effectively reduce the problem that the SAW device 1000 is easily burned out due to the current of the first gap region B11 being too large. In other embodiments, the number of the connecting portions 2111 can also be two, three or more, as long as the number of the connecting portions 2111 is less than the number of the finger portions 213 in the same electrode structure 21. When the number of the connecting portions 2111 includes at least two, the connecting portions 2111 are spacedly arranged along the second direction.

[0062] In some embodiments, the metallization rates of the finger portion 213 and the connecting strip 2111 are ε1 and ε2 respectively, 0.95ε1<ε2<1.05ε1; and / or, the metallization rate of the connecting strip 2111 is ε2, 0.15<ε2<0.75. If ε1 and / or ε2 is too small, the resistance of the surface acoustic wave device 1000 is large, which causes the surface acoustic wave device 1000 to be easily burnt out. In addition, if ε1 and / or ε2 is too small, the surface acoustic wave device 1000 is difficult to process. In addition, if ε1 and / or ε2 is too large, the positive and negative electrodes of the surface acoustic wave device 1000 are too close to be easily broken down. It also causes the acoustic velocity to be reduced, and the energy suppression effect to be weakened. 0.95ε1<ε2<1.05ε1 makes the surface acoustic wave device 1000 have high reliability, not easy to be burnt out, and not easy to be broken down due to the positive and negative electrodes being too close. In addition, it is easy to process, has high acoustic velocity, and has good energy suppression effect. Similarly, 0.15<ε2<0.75 makes the surface acoustic wave device 1000 have high reliability, not easy to be burnt out, and not easy to be broken down due to the positive and negative electrodes being too close. In addition, it is easy to process, has high acoustic velocity, and has good energy suppression effect.

[0063] Referring to FIG. 6, in some embodiments, the size of the conductive portion 212 along the first direction is W1, 0.1λ<W1<0.3λ, and λ is the wavelength of the surface acoustic wave device 1000. W1 being too small can easily cause the wire to be burnt out, and W1 being too large can reduce the spurious mode suppression effect on the high frequency side of the anti-resonance point. 0.1λ<W1<0.3λ can balance the better spurious mode suppression effect and reliability, has good spurious mode suppression effect on the high frequency side of the anti-resonance point, not easy to cause the wire to be burnt out, and can also make the surface acoustic wave device 1000 easy to process. For example, no conductive structure is provided in the preset region C3 where the first region C1 and the second region C2 overlap, 0.1λ<W1<0.3λ, which can more effectively suppress the spurious mode on the high frequency side of the anti-resonance point, and further improve the spurious mode suppression effect, and is easy to process.

[0064] In some embodiments, the acoustic velocity of the first gap region B11 is greater than the acoustic velocity of the second gap region B12. Forming such an acoustic velocity distribution in the non-intersection region B1 can achieve a higher resonant frequency of the surface acoustic wave device 1000, and achieve a filter in the high frequency band.

[0065] In some embodiments, the size of the second gap region B12 of the non-intersection region B1 along the first direction is less than 0.5λ, and λ is the wavelength of the surface acoustic wave device 1000. Being within this range is conducive to limiting energy and reducing energy leakage, and improving the Q value of the surface acoustic wave device 1000.

[0066] In some embodiments, the axis of the connection portion 211 of one of the electrode structures 21 in the first direction coincides with the axis of one of the finger portions 213 of the other electrode structure 21 in the first direction. In this way, the acoustic surface wave device 1000 is ensured to have an overall symmetric electric field distribution, thereby effectively ensuring the acoustic surface wave device 1000 to have a good excitation effect and improving the performance of the acoustic surface wave device 1000. For example, referring to FIG. 4, in the first electrode structure 21a, the axis of the first connection strip 2111a coincides with the axis of the second finger portion 2132b. In the second electrode structure 21b, the axis of the second connection strip 2111b coincides with the axis of the first finger portion 2131b. For example, in the same electrode structure 21, the connection strip 211 is arranged between two adjacent finger portions in the second direction.

[0067] Referring to FIG. 6, in some embodiments, the electrode structure 21 further comprises a dummy finger 214, the dummy finger 214 is connected with the bus bar 10, and the dummy finger 214 is arranged in the non-crossing region B1; the dummy finger 214 is arranged in the first direction at a distance from the finger end of one of the finger portions 213 of the other electrode structure 21. By arranging the dummy finger 214, the transverse mode interference of the acoustic surface wave device 1000 can be suppressed, the energy leakage can be reduced, and the Q value of the acoustic surface wave device 1000 can be improved.

[0068] For example, referring to FIG. 6, the number of the dummy fingers 214 includes a plurality of dummy fingers 214, the plurality of dummy fingers 214 includes a first dummy finger 2141 and a second dummy finger 2142, one end of the first dummy finger 2141 is connected with the first bus bar 11, and the other end of the first dummy finger 2141 is arranged in the first direction at a distance from the finger end of the second finger portion 2132a; one end of the second dummy finger 2142 is connected with the second bus bar 12, and the other end of the second dummy finger 2142 is arranged in the first direction at a distance from the finger end of the first finger portion 2131a. In the same electrode unit 20, the number of the first dummy fingers 2141 and the number of the second dummy fingers 2142 can be designed according to actual needs, such as one, two or more. For example, in the same electrode unit 20, the number of the first dummy fingers 2141 and the number of the second dummy fingers 2142 are both one.

[0069] It can be understood that when the acoustic surface wave device 1000 is provided with the first dummy finger 2141 and the second dummy finger 2142, the first gap region B11 is actually a region located between the first dummy finger 2141 and the first conductive portion 2121 in the first direction; or a region located between the second dummy finger 2142 and the second conductive portion 2122 in the first direction.

[0070] In some embodiments, the metallization rate of the dummy finger 214 ranges from [0.25, 0.8], such as 0.25, 0.5, 0.8 or any other suitable value between 0.25 and 0.8. It can be understood that if the metallization rate of the dummy finger 214 is too small, the resistance of the surface acoustic wave device 1000 is large, which causes the surface acoustic wave device 1000 to be easily burned out. In addition, if the metallization rate of the dummy finger 214 is too small, the surface acoustic wave device 1000 is difficult to process. If the metallization rate of the dummy finger 214 is too large, the positive and negative electrodes of the surface acoustic wave device 1000 are too close to be easily broken down. In addition, the speed of sound is reduced, and the energy suppression effect is also weakened. The range of the metallization rate of the dummy finger 214 is [0.25, 0.8], which makes the surface acoustic wave device 1000 have high reliability, is not easy to be burned out, and is not easy to be broken down due to the positive and negative electrodes being too close. In addition, the surface acoustic wave device 1000 is easy to process, has high speed of sound, and has good energy suppression effect.

[0071] In some embodiments, the size of the dummy finger 214 along the first direction ranges from (0.1um, 0.5λ), and λ is the wavelength of the surface acoustic wave device 1000. The size of the dummy finger 214 along the first direction is within the range, which can better suppress the transverse mode interference of the surface acoustic wave device 1000, effectively reduce energy leakage, and thus effectively improve the Q value of the surface acoustic wave device 1000.

[0072] For example, the interval distance between the dummy finger 214 and the finger end of the corresponding finger strip part 213 along the first direction is greater than the size of the preset region C3 along the first direction. For example, referring to FIG. 6, the interval distance between the one end of the first dummy finger 2141 away from the first bus bar 11 and the finger end of the second finger strip part 2132a along the first direction is greater than the size of the preset region C3 along the first direction.

[0073] For example, the interval distance between the dummy finger 214 and the finger end of the corresponding finger strip part 213 along the first direction is greater than 0.8λ, and λ is the wavelength of the surface acoustic wave device 1000. For example, referring to FIG. 6, the interval distance between the one end of the first dummy finger 2141 away from the first bus bar 11 and the finger end of the second finger strip part 2132a along the first direction is greater than 0.8λ.

[0074] The number of electrode units 20 of the surface acoustic wave device 1000 can include one, two, three or more. In some embodiments, referring to FIG. 7, the number of electrode units 20 includes at least two, each electrode unit 20 is arranged between two bus bars 10; in the second direction, each electrode unit 20 is arranged at intervals. Referring to FIG. 7, for example, the number of electrode units 20 includes at least two, at least two electrode units 20 are arranged at intervals along the second direction; wherein the two electrode units 20 are respectively located at the two transverse edges of the interdigital transducer 200 along the second direction, so as to ensure that the surface acoustic wave device 1000 has good excitation effect and improve the performance of the surface acoustic wave device 1000. For example, the number of electrode units 20 includes at least two; in the same non-crossing area B1, the conductive part 212 of each electrode unit 20 is arranged at intervals along the second direction.

[0075] In some embodiments, in addition to the finger part 213 of the electrode unit 20, the interdigital transducer 200 does not include an electrode finger directly connected to the first bus bar 11 and the second bus bar 12 at both ends. In other embodiments, in addition to the finger part 213 of the electrode unit 20, the interdigital transducer 200 can further include a plurality of electrode fingers directly connected to the first bus bar 11 and the second bus bar 12 at both ends, and the plurality of electrode fingers are arranged alternately and at intervals in the second direction.

[0076] Referring to FIG. 2, in some embodiments, the surface acoustic wave device 1000 further includes a dielectric layer 30, the dielectric layer 30 covers the interdigital transducer 200, and the dielectric layer 30 is arranged on the side of the finger part 213 away from the piezoelectric substrate 100. The dielectric layer 30 can protect the interdigital transducer 200 and / or other components of the surface acoustic wave device 1000. The dielectric layer 30 can completely cover the interdigital transducer 200, or it can not completely cover the interdigital transducer 200, for example, only cover the area where the electrode structure 21 of the interdigital transducer 200 is located, while the bus bar 10 is not covered.

[0077] In some embodiments, the medium layer 30 comprises at least one of a temperature compensation layer, a frequency tuning layer, and a passivation layer. In some embodiments, the medium layer 30 is a temperature compensation layer. The temperature compensation layer is used to improve the temperature characteristics of the SAW device 1000, and the material of the temperature compensation layer can be silicon oxide, silicon nitride, silicon oxynitride, or other dielectric. In some embodiments, the material of the temperature compensation layer is one of the above materials, i.e., the material of the temperature compensation layer is a single material. Of course, the material of the temperature compensation layer can also be a mixed material, in which case the material of the temperature compensation layer can be a mixture of any of the above materials, or a mixture of one or more of the above materials and other materials. In other embodiments, the medium layer 30 can also comprise at least one of a frequency tuning layer and a passivation layer. The frequency tuning layer is used to adjust the frequency of the SAW device 1000. The material of the frequency tuning layer can be at least one of silicon dioxide, silicon nitride, aluminum nitride, aluminum oxide, silicon oxyfluoride, silicon oxynitride, or other materials. The passivation layer is used to protect the IDT 200 and / or other components of the SAW device 1000. The material of the passivation layer can be at least one of silicon dioxide, silicon nitride, aluminum nitride, aluminum oxide, silicon oxyfluoride, silicon oxynitride, or other materials.

[0078] Referring to FIG. 3, in some embodiments, the edge region A12 is provided with a low sound speed portion 40, the sound speed of the region provided with the low sound speed portion 40 is less than the sound speed of the middle region A11, the low sound speed portion 40 can adjust the sound speed of the region where the low sound speed portion 40 is located, thereby adjusting the sound speed distribution of the intersection region A1, so that the sound speed of the SAW device 1000 can form a piston mode, thereby effectively suppressing the transverse mode and improving the performance of the SAW device 1000. For example, the low sound speed portion 40 is provided so that the sound speed of the edge region A12 is reduced; and the sound speed of the second gap region B12, the sound speed of the middle region A11, and the sound speed of the edge region A12 are sequentially reduced, so that the second gap region B12, the middle region A11, and the edge region A12 form a piston mode, which can effectively suppress the transverse mode and improve the performance of the SAW device 1000.

[0079] For example, the sound speed of the second gap region B12, the sound speed of the middle region A11, and the sound speed of the edge region A12 are sequentially reduced, and the second gap region B12, the middle region A11, and the edge region A12 form a piston mode; the conductive portion 212, the second gap region B12, and the edge region A12 together form a low sound speed region, the first gap region B11, the low sound speed region, and the middle region A11 form another piston mode, and the double piston mode can more effectively suppress the transverse mode and more effectively confine the elastic wave. It can be understood that when the sound speed of the first gap region B11 is large enough, the energy can be effectively confined in the potential well formed by the double piston mode.

[0080] Exemplarily, the low sound velocity part 40 can include at least one of the following structures: a widening part, a thickening part, and a mass loading structure. Exemplarily, the widening part refers to a part of the finger strip part 213, i.e., the part of the finger strip part 213 located in the edge area A12 is widened in the second direction compared with the part of the finger strip part 213 located in the middle area A11. The thickening part refers to a part of the finger strip part 213, i.e., the part of the finger strip part 213 located in the edge area A12 is thickened in the top view direction compared with the part of the finger strip part 213 located in the middle area A11. Exemplarily, the top view direction in the embodiment is perpendicular to the first direction and the second direction. The mass loading structure includes a mass loading block or a mass loading strip.

[0081] As shown in FIGS. 8-11, the surface acoustic wave device 1000 of the embodiment of the present application is compared with the surface acoustic wave device 1000 of the related art.

[0082] FIG. 8 is a comparison diagram of the admittance curves of the surface acoustic wave devices 1000 of the related art and the embodiment of the present application, in which the dashed line e1 is a schematic diagram of the admittance curve of the surface acoustic wave device 1000 of the related art, the dashed line e2 is a schematic diagram of the real part of the admittance curve of the surface acoustic wave device 1000 of the related art, the solid line d1 is a schematic diagram of the admittance curve of the surface acoustic wave device 1000 of the embodiment of the present application, and the solid line d2 is a schematic diagram of the real part of the admittance curve of the surface acoustic wave device 1000 of the embodiment of the present application. In FIG. 8, the horizontal axis is frequency, and the unit is Hz; and the vertical axis is admittance, and the unit is dB. In FIG. 8, the surface acoustic wave device 1000 of the embodiment of the present application includes at least two electrode units 20, and the conductive parts 212 of each electrode unit 20 are arranged at intervals in the second direction; in the same electrode structure 21, the number of the connecting strips 2111 is less than the number of the finger strip parts 213. The surface acoustic wave device 1000 of the related art in FIG. 8 includes two electrode units, and the conductive parts 212 of each electrode unit are connected together in the second direction, i.e., the conductive parts 212 of each electrode unit are connected and form a continuous and uninterrupted structure in the second direction; in the same electrode structure 21, the number of the connecting strips 2111 is equal to the number of the finger strip parts 213. As can be seen from FIG. 8, in the frequency interval of F1-F2, the mode mixing of the surface acoustic wave device 1000 of the embodiment of the present application is significantly reduced compared with the surface acoustic wave device 1000 of the related art.

[0083] Figure 9 is a comparison diagram of admittance curves of the surface acoustic wave device 1000 of the related art and an embodiment of the present application, wherein the dashed line e3 is a schematic diagram of the admittance curve of the surface acoustic wave device 1000 of the related art; the dashed line e4 is a schematic diagram of the real part of the admittance curve of the surface acoustic wave device 1000 of the related art; the solid line d3 is a schematic diagram of the admittance curve of the surface acoustic wave device 1000 of an embodiment of the present application; and the solid line d4 is a schematic diagram of the real part of the admittance curve of the surface acoustic wave device 1000 of an embodiment of the present application. The horizontal axis of Figure 9 is frequency, in Hz; and the vertical axis is admittance, in dB. In Figure 9, the surface acoustic wave device 1000 of an embodiment of the present application has a number of connecting strips 2111 less than a number of finger strips 213 in the same electrode structure 21. In Figure 9, the surface acoustic wave device of the related art has a number of connecting strips 2111 equal to a number of finger strips 213 in the same electrode structure 21. As shown in Figure 9, the surface acoustic wave device 1000 of an embodiment of the present application has a significantly reduced mode mixing relative to the surface acoustic wave device 1000 of the related art when the frequency is in the interval of F3 to F4.

[0084] Figure 10 is a comparison diagram of admittance curves of the surface acoustic wave device 1000 of the related art and an embodiment of the present application, wherein the dashed line e5 is a schematic diagram of the admittance curve of the surface acoustic wave device 1000 of the related art; the dashed line e6 is a schematic diagram of the real part of the admittance curve of the surface acoustic wave device 1000 of the related art; the solid line d5 is a schematic diagram of the admittance curve of the surface acoustic wave device 1000 of an embodiment of the present application; and the solid line d6 is a schematic diagram of the real part of the admittance curve of the surface acoustic wave device 1000 of an embodiment of the present application. The horizontal axis of Figure 10 is frequency, in Hz; and the vertical axis is admittance, in dB. In Figure 10, the surface acoustic wave device 1000 of an embodiment of the present application has no conductive structure in the preset region C3. In Figure 10, the surface acoustic wave device 1000 corresponding to the dashed line has a conductive structure in the preset region C3. As shown in Figure 10, the surface acoustic wave device 1000 of an embodiment of the present application has a significantly reduced mode mixing relative to the surface acoustic wave device 1000 of the related art when the frequency is in the interval of F5 to F6.

[0085] FIG. 11 is a Q value comparison diagram of the surface acoustic wave device 1000 of the related art and an embodiment of the present application, where the dashed line e7 is a schematic diagram of the Q value of the surface acoustic wave device 1000 of the related art, and the solid line d7 is a schematic diagram of the Q value of the surface acoustic wave device 1000 of an embodiment of the present application. The horizontal axis of FIG. 11 is frequency, in Hz, and the vertical axis is Q value, in dB. In FIG. 11, the surface acoustic wave device 1000 of the embodiment of the present application has a number of connecting strips 2111 less than a number of finger strips 213 in the same electrode structure 21. In FIG. 11, the surface acoustic wave device of the related art has a number of connecting strips 2111 equal to a number of finger strips 213 in the same electrode structure 21. As can be seen from FIG. 11, the Q value of the surface acoustic wave device 1000 of the embodiment of the present application is significantly improved when the frequency is within the interval frequency of F7 to F8 and within the interval frequency of F9 to F10. It can be understood that the frequencies of FIG. 11 correspond to the frequencies of FIG. 9, and the Bode image is smoothed.

[0086] An embodiment of the present application further provides a surface acoustic wave device 1000, which comprises a piezoelectric substrate 100 and an interdigital transducer 200, the interdigital transducer 200 being arranged on the piezoelectric substrate 100; the interdigital transducer 200 comprises an electrode unit 20 and two bus bars 10, the two bus bars 10 being arranged opposite to each other along a first direction; the electrode unit 20 comprises two electrode structures 21, the two electrode structures 21 being arranged between the two bus bars 10; each of the two electrode structures 21 is connected to one of the two bus bars 10; each of the electrode structures 21 comprises a connecting part 211, a conductive part 212, and at least two finger strips 213, the connecting part 211 comprises a connecting strip 2111, the bus bar 10 is connected to the conductive part 212 through the connecting strip 2111, and the finger strip 213 of the electrode structure 21 is connected to the conductive part 212; each of the finger strips 213 is arranged in a second direction perpendicular to the first direction; in the first direction, the two bus bars 10 have a crossing area A1 and a non-crossing area B1 between them, the connecting part 211 and the conductive part 212 are arranged in the non-crossing area B1; in the second direction, the crossing area A1 is an area in which the finger strips 213 overlap each other. In the same electrode structure 21, the number of the connecting strips 2111 is less than the number of the finger strips 213, and in the first direction, a tip end of at least one of the finger strips 213 of the electrode structure 21 is not provided with a conductive structure within a preset distance from the tip end, the preset distance is less than or equal to 0.8λ, and λ is the wavelength of the surface acoustic wave device 1000.

[0087] The surface acoustic wave device 1000 of the above embodiment can change the original periodicity of the finger strip part 213 by connecting at least two finger strip parts 213 through the conductive part 212, so as to weaken the spurious mode; and since the number of the connecting strips 2111 in the same electrode structure 21 is less than the number of the finger strip parts 213, that is, the at least two finger strip parts 213 connected together are connected to the bus bar 10 through less connecting strips 2111, the possibility of generating an equivalent resonant cavity in the non-intersection area B1 can be reduced, so as to reduce the possibility of the spurious mode being excited, to reduce or avoid the probability of the acoustic wave energy in the intersection area A1 leaking to the non-intersection area B1 being excited as far as possible, and to realize the suppression of the spurious mode, so as to reduce or avoid the influence of the spurious mode on the performance of the surface acoustic wave device 1000. In addition, since the finger end of the at least one finger strip part 213 of the electrode structure 21 in the first direction is not provided with a conductive structure within a preset distance from the finger end, and the preset distance is less than or equal to 0.8λ, compared with the case that the conductive structure is provided within the preset distance, the embodiment of the present application can effectively suppress the spurious mode on the high-frequency side of the anti-resonance point, improve the spurious mode suppression effect, is simple to process, is conducive to saving the use of conductive material, and is conducive to realizing the light weight and cost reduction of the product.

[0088] For example, referring to FIG. 4, the at least one second finger strip part 2132 of the second electrode structure 21b includes a second finger strip part 2132a, and the finger end of the second finger strip part 2132a is not provided with a conductive structure within a preset distance from the finger end, and the area corresponding to the preset distance is located in the non-intersection area B1. The at least one first finger strip part 2131 of the first electrode structure 21a includes a first finger strip part 2131a, and the finger end of the first finger strip part 2131a is not provided with a conductive structure within a preset distance from the finger end, and the area corresponding to the preset distance is located in the non-intersection area B1.

[0089] Referring to FIG. 3, in some embodiments, the non-intersection area B1 includes a first gap area B11, which is the area between the bus bar 10 and the conductive part 212. The area where the finger end of the at least one finger strip part 213 of the electrode structure 21 extends in the first direction towards the bus bar 10 connected by the other electrode structure 21 is defined as a first area C1, the area in the non-intersection area B1 except the first gap area B11 is a second area C2, and the area where the first area C1 and the second area C2 overlap each other is a preset area C3; and the preset area C3 is not provided with a conductive structure. Since the preset area C3 where the first area C1 and the second area C2 overlap each other is not provided with a conductive structure, compared with the case that the conductive structure is provided in the preset area C3, the embodiment of the present application can effectively suppress the spurious mode on the high-frequency side of the anti-resonance point, improve the spurious mode suppression effect, is simple to process, is conducive to saving the use of conductive material, and is conducive to realizing the light weight and cost reduction of the product.

[0090] In addition, the piezoelectric substrate 1 and the interdigital transducer 2 in this embodiment are arranged in the same manner as in the above embodiments, and thus will not be described here.

[0091] The embodiment of the present application further provides a surface acoustic wave device 1000, which comprises a piezoelectric substrate 100 and an interdigital transducer 200, the interdigital transducer 200 is arranged on the piezoelectric substrate 100; the interdigital transducer 200 comprises an electrode unit 20 and two bus bars 10, the two bus bars 10 are arranged oppositely and spaced apart along a first direction; the electrode unit 20 comprises two electrode structures 21, the two electrode structures 21 are arranged between the two bus bars 10; each of the two electrode structures 21 is connected with one of the two bus bars 10; the electrode structure 21 comprises a connecting part 211, a conductive part 212 and at least two finger parts 213, the connecting part 211 comprises a connecting strip 2111, the bus bar 10 is connected with the conductive part 212 through the connecting strip 2111, and the finger part 213 of the electrode structure 21 is connected with the conductive part 212; each of the finger parts 213 is arranged spaced apart along a second direction perpendicular to the first direction; in the first direction, the two bus bars 10 have a crossing area A1 and a non-crossing area B1 between them, the connecting part 211 and the conductive part 212 are arranged in the non-crossing area B1; in the second direction, the crossing area A1 is an area in which the finger parts 213 overlap with each other. In the same electrode structure 21, the number of the connecting strips 2111 is less than the number of the finger parts 213; the finger parts 213 of the two electrode structures 21 are respectively first finger parts 2131 and second finger parts 2132, one of the electrode structures 21 comprises a first sub-unit 21c, and the other electrode structure 21 comprises a second sub-unit 21d, the first sub-unit 21c and the second sub-unit 21d are arranged alternately and spaced apart along the second direction; the first sub-unit 21c comprises at least two adjacent first finger parts 2131, and the second sub-unit 21d comprises at least two adjacent second finger parts 2132.

[0092] The surface acoustic wave device 1000 of the above embodiment can change the original periodicity of the finger strip part 213 by connecting at least two finger strip parts 213 through the conductive part 212, so as to weaken the spurious mode; and since the number of the connecting strips 2111 in the same electrode structure 21 is less than the number of the finger strip parts 213, that is, the at least two finger strip parts 213 connected together are connected to the bus bar 10 through less connecting strips 2111, the possibility of generating an equivalent resonant cavity in the non-crossing area B1 can be reduced, so as to reduce the possibility of the spurious mode being excited, to reduce or avoid the probability of the acoustic wave energy in the crossing area A1 leaking to the non-crossing area B1 being excited as far as possible, and to realize the suppression of the spurious mode, so as to reduce or avoid the influence of the spurious mode on the performance of the surface acoustic wave device 1000. In addition, since one of the electrode structures 21 includes the first sub-unit 21c, and the other electrode structure 21 includes the second sub-unit 21d, the first sub-unit 21c and the second sub-unit 21d are alternately and spacedly arranged along the second direction; the first sub-unit 21c includes at least two adjacent first finger strip parts 2131, and the second sub-unit 21d includes at least two adjacent second finger strip parts 2132, so as to improve the Q value of the surface acoustic wave device 1000, and to be applicable to higher frequency bands such as 5G and above.

[0093] Please refer to FIG. 3, in some embodiments, the non-crossing area B1 includes a first gap area B11, the first gap area B11 is the area between the bus bar 10 and the conductive part 212, the area where the finger end of at least one finger strip part 213 of the electrode structure 21 extends along the first direction towards the bus bar 10 connected by the other electrode structure 21 is defined as a first area C1, the area in the non-crossing area B1 except the first gap area B11 is a second area C2, the area where the first area C1 and the second area C2 overlap each other is a preset area C3; no conductive structure is arranged in the preset area C3. Since no conductive structure is arranged in the preset area C3 where the first area C1 and the second area C2 overlap each other, compared with arranging a conductive structure in the preset area C3, the embodiment of the application can effectively suppress the spurious mode on the high frequency side of the anti-resonance point, improve the spurious mode suppression effect; simple processing; it is beneficial to save the use of conductive material, thereby facilitating the realization of the light weight and cost reduction of the product.

[0094] In addition, the piezoelectric substrate 1 and the interdigital transducer 2 in the embodiment are arranged in the same way as in the above embodiments, which will not be described here.

[0095] The embodiment of the present application also provides a surface acoustic wave device 1000, which comprises a piezoelectric substrate 100 and an interdigital transducer 200 arranged on the piezoelectric substrate 100; the interdigital transducer 200 comprises electrode units 20 and two bus bars 10 arranged oppositely and spaced apart along a first direction; each electrode unit 20 comprises two electrode structures 21 arranged between the two bus bars 10; each electrode structure 21 is connected to one bus bar 10; each electrode structure 21 comprises a connecting part 211, a conductive part 212 and at least two finger parts 213; the connecting part 211 comprises a connecting strip 2111, the bus bar 10 is connected to the conductive part 212 through the connecting strip 2111, and the finger part 213 of the electrode structure 21 is connected to the conductive part 212; each finger part 213 is arranged in a second direction perpendicular to the first direction; in the first direction, the two bus bars 10 have a crossing area A1 and a non-crossing area B1, and the connecting part 211 and the conductive part 212 are arranged in the non-crossing area B1; in the second direction, the crossing area A1 is an area in which the finger parts 213 overlap each other. In the same electrode structure 21, the number of connecting strips 2111 is less than the number of finger parts 213, and the ratio of the number of finger parts 213 to the number of connecting strips 2111 is A, A is greater than 1 and less than or equal to 8.

[0096] The surface acoustic wave device 1000 of the above embodiment can change the original periodicity of the finger parts 213 by connecting the at least two finger parts 213 through the conductive part 212, so as to weaken the spurious mode; and since the number of connecting strips 2111 is less than the number of finger parts 213 in the same electrode structure 21, that is, the at least two finger parts 213 connected together are connected to the bus bar 10 through less connecting strips 2111, the possibility of generating an equivalent resonant cavity in the non-crossing area B1 can be reduced, so as to reduce the possibility of starting the spurious mode, to reduce or avoid the probability that the acoustic wave energy leaked from the crossing area A1 to the non-crossing area B1 is excited as much as possible, and to realize the suppression of the spurious mode, so as to reduce or avoid the influence of the spurious mode on the performance of the surface acoustic wave device 1000. In addition, since the ratio A of the number of finger parts 213 to the number of connecting strips 2111 is greater than 1 and less than or equal to 8, the possibility of generating an equivalent resonant cavity in the non-crossing area B1 can be effectively reduced, so as to effectively reduce the possibility of starting the spurious mode, to avoid the acoustic wave energy leaked from the crossing area A1 to the non-crossing area B1 from being excited as much as possible, and to effectively realize the suppression of the spurious mode; in addition, A is located in the range, which can effectively reduce the mass of the connecting part 211, and also make the connecting part 211 and the finger parts 213 have appropriate equivalent resistance, and make the surface acoustic wave device 1000 more reliable, and effectively reduce the problem that the surface acoustic wave device 1000 is easily burned out due to excessive current in the first gap area B11.

[0097] Referring to FIG. 3, in some embodiments, the non-crossing area B1 includes a first gap area B11, which is an area between the bus bar 10 and the conductive part 212. The first area C1 is defined as an area in which a finger end of at least one finger portion 213 of the electrode structure 21 extends in a first direction toward the bus bar 10 to which the other electrode structure 21 is connected. The second area C2 is an area in the non-crossing area B1 other than the first gap area B11. The preset area C3 is an area in which the first area C1 and the second area C2 overlap each other. No conductive structure is provided in the preset area C3. Compared with the case where a conductive structure is provided in the preset area C3, the embodiment of the present application can effectively suppress the high-frequency side of the anti-resonance point, improve the mode suppression effect, and is simple to process. The embodiment is conducive to saving the use of conductive materials, thereby facilitating the lightweight and cost reduction of the product.

[0098] In addition, the piezoelectric substrate 1 and the interdigital transducer 2 in the embodiment are arranged in the same manner as in the above embodiments, and thus will not be described herein.

[0099] The embodiment of the present application also provides a surface acoustic wave device 1000.

[0100] Exemplarily, the filter includes a plurality of surface acoustic wave devices 1000, wherein at least one surface acoustic wave device 1000 includes the surface acoustic wave device 1000 of any one of the above embodiments. The structures of the surface acoustic wave devices 1000 can be the same or different, which is not limited herein.

[0101] The embodiment of the present application also provides a radio frequency front-end module including the surface acoustic wave device 1000 of any one of the above embodiments.

[0102] In some embodiments, the radio frequency front-end module can be applied to an electronic device, which can include but is not limited to an LED panel, a tablet computer, a notebook computer, a computer, a navigator, a mobile phone, an electronic watch and other electronic devices having a PCB, or a part thereof.

[0103] In the present application, unless specifically defined and limited otherwise, "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact or not in direct contact but in contact through another feature between them. Moreover, "on", "above" and "over" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the first feature is higher than the second feature in horizontal height. "Under", "below" and "underneath" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the first feature is lower than the second feature in horizontal height.

[0104] The foregoing disclosure provides many different embodiments or examples for implementing different structures of the present application. For simplicity of disclosure, the foregoing description has focused on certain examples of components and arrangements of parts. Alternatives, of course, will be apparent to those of ordinary skill in the art and can be implemented without departing from the scope of the application. Additionally, disclosure of a single item, includes multiples of such items, unless otherwise indicated. For example, references to a structure or component, include references to one or more structures or components. Unless otherwise noted, the terms used in the description are defined as follows:

[0105] In this description, reference has been made to terminology such as "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" meant to include a particular feature, structure, material, or characteristic. Such terminology may or may not be present in other instances. The term "exemplary" does not necessarily refer to a kin or preferred embodiment-nor does it necessarily refer to an example that is the best of all possible examples. The terminology simply indicates that the feature, structure, material, or characteristic is an example of a particular implementation. Furthermore, the description may use perspective-based descriptions such as up or down, front or back, and the like. Such adjectives are merely used herein for clarity and example, unless otherwise noted.

[0106] The above description is only specific implementation of the present application. Obviously, not to limit the scope of the application, any person skilled in the art within the scope of the present application, can easily think of various equivalent modifications or replacements, these modifications or replacements should be covered in the scope of the present application. Therefore, the scope of the present application should be subject to the scope of claims.

Claims

1. A surface acoustic wave device, wherein, The surface acoustic wave device comprises a piezoelectric substrate and an interdigital transducer provided on the piezoelectric substrate; the interdigital transducer comprises: Two bus bars, the two bus bars are oppositely arranged along a first direction; An electrode unit comprising two electrode structures, the two electrode structures are arranged between the two bus bars; each of the two electrode structures is connected to one of the bus bars; the electrode structure comprises a connecting portion, a conductive portion and at least two finger portions, the connecting portion comprises a connecting strip, the bus bar is connected to the conductive portion through the connecting strip, and the finger portion of the electrode structure is connected to the conductive portion; each of the finger portions is arranged in a second direction perpendicular to the first direction; in the first direction, the two bus bars have a crossing area and a non-crossing area between them, and the connecting portion and the conductive portion are arranged in the non-crossing area; in the second direction, the crossing area is an area in which the finger portions of the electrode structures overlap each other; In the same electrode structure, the number of connecting strips is less than the number of finger portions; the non-crossing area comprises a first gap area, which is an area between the bus bar and the conductive portion; the area in which the finger end of at least one finger portion of the electrode structure extends along the first direction towards the bus bar connected to the other electrode structure is defined as a first area, the area in the non-crossing area other than the first gap area is a second area, and the area in which the first area and the second area overlap each other is a preset area; no conductive structure is arranged in the preset area.

2. The SAW device of claim 1, wherein, The size of the preset area in the first direction is less than or equal to 0.8λ, and λ is the wavelength of the surface acoustic wave device.

3. The SAW device of claim 1, wherein, The finger portions of the two electrode structures are respectively a first finger portion and a second finger portion; one of the electrode structures comprises a first sub-unit, and the other electrode structure comprises a second sub-unit, the first sub-unit and the second sub-unit are alternately arranged along the second direction; the first sub-unit comprises at least two adjacent first finger portions, and the second sub-unit comprises at least two adjacent second finger portions.

4. The SAW device of claim 3, wherein, The number of first finger portions and second finger portions is even, the number of first finger portions of the first sub-unit is the same as the number of second finger portions of the second sub-unit, all the first finger portions form at least two first sub-units, and the number of first finger portions of each first sub-unit is the same; all the second finger portions form at least two second sub-units, and the number of second finger portions of each second sub-unit is the same.

5. The SAW device of claim 1, wherein, In the same electrode unit, the finger portions of one of the electrode structures are alternately arranged with the finger portions of the other electrode structure.

6. The SAW device of claim 1, wherein, In the same electrode structure, the ratio of the number of finger portions to the number of connecting strips is A, A is greater than 1 and less than or equal to 8.

7. The SAW device of claim 1, wherein, The metallization rates of the finger portions and the connecting strips are respectively ε1 and ε2, 0.95ε1<ε2<1.05ε1; and / or, The metallization rate of the connecting strip is ε2, 0.15<ε2<0.

75.

8. The SAW device of claim 1, wherein, The conductive part has a dimension W1 in the first direction, and 0.1λ < W1 < 0.3λ, where λ is the wavelength of the surface acoustic wave device.

9. The SAW device of claim 1, wherein, The non-crossing area includes a first gap area and a second gap area, the first gap area is an area between the bus bar and the conductive part, and the second gap area is an area between the crossing area and the conductive part, and the sound velocity of the first gap area is greater than the sound velocity of the second gap area.

10. The SAW device of claim 1, wherein, The non-crossing area includes a second gap area, the second gap area is an area between the crossing area and the conductive part, and the dimension of the second gap area in the first direction is less than 0.5λ, where λ is the wavelength of the surface acoustic wave device.

11. The surface acoustic wave device of claim 1, wherein the axis of the connecting part of one of the electrode structures in the first direction coincides with the axis of one of the finger parts of another of the electrode structures in the first direction.

12. The SAW device of claim 1, wherein, The electrode structure further includes: The false finger is connected with the bus bar and is arranged in the non-crossing area; the tip of the false finger and one of the finger parts of another of the electrode structures are arranged in the first direction.

13. The SAW device of claim 12, wherein, The metallization rate of the false finger ranges from [0.25, 0.8]; and / or, The dimension of the false finger in the first direction ranges from (0.1um, 0.5λ), where λ is the wavelength of the surface acoustic wave device.

14. The SAW device of claim 1, wherein, The number of electrode units includes at least two, and at least two electrode units are arranged in the second direction; wherein two electrode units are respectively located at two lateral edges of the interdigital transducer in the second direction.

15. The surface acoustic wave device of claim 1, further comprising: A dielectric layer covering the interdigital transducer, the dielectric layer being arranged on the side of the finger part away from the piezoelectric substrate, and the dielectric layer including at least one of the following: a temperature compensation layer, a frequency modulation layer, and a passivation layer.

16. The SAW device of claim 1, wherein, The piezoelectric substrate includes a piezoelectric film and a substrate arranged in a stack, and the interdigital transducer is arranged on the surface of the piezoelectric film away from the substrate.

17. The SAW device of claim 1, wherein, The crossing area includes an intermediate area and edge areas located on both sides of the intermediate area, and the edge areas are provided with low sound velocity parts, and the sound velocity of the area provided with the low sound velocity parts is less than the sound velocity of the intermediate area.

18. A surface acoustic wave device, wherein, The surface acoustic wave device includes a piezoelectric substrate and an interdigital transducer, and the interdigital transducer is arranged on the piezoelectric substrate; the interdigital transducer includes: Two bus bars, and the two bus bars are arranged in the first direction. The electrode unit comprises two electrode structures, and the two electrode structures are arranged between two bus bars; each of the two electrode structures is connected to one of the bus bars; the electrode structure comprises a connecting portion, a conductive portion, and at least two finger portions; the connecting portion comprises a connecting strip, the bus bar is connected to the conductive portion through the connecting strip, and the finger portions of the electrode structure are connected to the conductive portion; the finger portions are arranged in a second direction perpendicular to the first direction; in the first direction, the two bus bars have a crossing area and a non-crossing area, and the connecting portion and the conductive portion are arranged in the non-crossing area; in the second direction, the crossing area is an area in which the finger portions overlap each other. In one of the electrode structures, the number of the connecting strips is less than the number of the finger portions; the finger portions of the two electrode structures are respectively first finger portions and second finger portions; one of the electrode structures comprises a first sub-unit, and the other electrode structure comprises a second sub-unit; the first sub-unit and the second sub-unit are arranged alternately in the second direction; the first sub-unit comprises at least two adjacent first finger portions, and the second sub-unit comprises at least two adjacent second finger portions.

19. A filter comprising the surface acoustic wave device of claim 1.

20. A radio frequency front-end module comprising the surface acoustic wave device of claim 1.

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