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, an interdigital transducer and auxiliary structures, wherein in the arrangement direction of electrode fingers of the interdigital transducer, the overlap region is a region where the electrode fingers overlap with each other; each electrode finger comprises a widened portion, which is located in an edge region; and the acoustic impedance of a region in which a widened portion is provided is different from the acoustic impedance of a region in which an auxiliary structure is provided. Thus, a high-order transverse mode and a low-order transverse mode are better suppressed.

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 piezoelectric substrate by using a feature of an acoustic-electric transducer. The surface acoustic wave device has advantages of low cost, small size and multiple functions, and thus is widely applied in 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. A transverse mode of the surface acoustic wave device causes acoustic wave leakage, thereby causing acoustic energy loss and reducing a quality factor value. However, the surface acoustic wave device in the related art has an unreasonable structure design, and the suppression effect on the transverse mode of the surface acoustic wave device is not ideal. SUMMARY

[0003] The present application provides a surface acoustic wave device, a filter and a radio frequency front-end module, and aims to better suppress high-order transverse modes and low-order transverse modes.

[0004] The present application provides a surface acoustic wave device, which comprises:

[0005] a piezoelectric substrate;

[0006] an interdigital transducer arranged on the piezoelectric substrate; in a direction in which two bus bars of the interdigital transducer are arranged, the two bus bars have a crossing area between them, the crossing area includes a middle area and edge areas located at two ends of the middle area; in a direction in which each electrode finger of the interdigital transducer is arranged, the crossing area is an area in which each electrode finger overlaps with each other; the electrode finger includes a widened part located in the edge area;

[0007] an auxiliary structure located in the edge area;

[0008] In the same edge area, a projection of the widened part and the auxiliary structure in a top view direction is at least partially staggered in a length extension direction of the electrode finger, an acoustic impedance of an area provided with the widened part is different from an acoustic impedance of an area provided with the auxiliary structure.

[0009] The present application further provides a surface acoustic wave device, which comprises:

[0010] a piezoelectric substrate;

[0011] The interdigital transducer is arranged on the piezoelectric substrate; in the arrangement direction of two bus bars of the interdigital transducer, the two bus bars have a crossing area between them, the crossing area includes a middle area and edge areas located at both ends of the middle area; in the arrangement direction of each electrode finger of the interdigital transducer, the crossing area is an area in which each electrode finger overlaps with each other; the electrode finger includes a widened part located in the edge area;

[0012] The accessory structure is arranged in at least one of the two edge areas;

[0013] In the same edge area, the projection of the widened part and the accessory structure in the top view direction is at least partially staggered in the length extension direction of the electrode finger;

[0014] The accessory structure is a conductive structure, the accessory structure includes a plurality of accessory blocks, each accessory block is arranged in sequence and is spaced apart in the arrangement direction of each electrode finger; in the top view direction, each electrode finger is arranged in conjunction with an accessory block;

[0015] The medium layer is arranged on the piezoelectric substrate and covers the interdigital transducer and the accessory structure.

[0016] The embodiment of the present application also provides a surface acoustic wave device, which comprises:

[0017] The piezoelectric substrate;

[0018] The interdigital transducer is arranged on the piezoelectric substrate; in the arrangement direction of two bus bars of the interdigital transducer, the two bus bars have a crossing area between them, the crossing area includes a middle area and edge areas located at both ends of the middle area; in the arrangement direction of each electrode finger of the interdigital transducer, the crossing area is an area in which each electrode finger overlaps with each other; the electrode finger includes a widened part located in the edge area;

[0019] The accessory structure is arranged in at least one of the two edge areas;

[0020] In the same edge area, the projection of the widened part and the accessory structure in the top view direction is at least partially staggered in the length extension direction of the electrode finger; the accessory structure is a non-conductive structure; in the top view direction, a medium layer is arranged between the accessory structure and the interdigital transducer.

[0021] The embodiment of the present application also provides a surface acoustic wave device, which comprises:

[0022] The piezoelectric substrate;

[0023] The interdigital transducer is arranged on the piezoelectric substrate; in the arrangement direction of two bus bars of the interdigital transducer, the two bus bars have a crossing area between them, the crossing area includes a middle area and edge areas located at both ends of the middle area; in the arrangement direction of each electrode finger of the interdigital transducer, the crossing area is an area in which each electrode finger overlaps with each other; the electrode finger includes a widened part located in the edge area;

[0024] An auxiliary structure is located in the edge area, the auxiliary structure includes a first area, a second area and a third area, in the length extension direction of the electrode finger, the first area and the third area are respectively located on the two sides away from the second area;

[0025] In the same edge area, the auxiliary structure covers the widened part, and the projection of the second area in the top view direction overlaps with the widened part along the length extension direction of the electrode finger.

[0026] Embodiments of the present application also provide a surface acoustic wave device, which comprises:

[0027] A piezoelectric substrate;

[0028] An interdigital transducer arranged on the piezoelectric substrate; in the arrangement direction of two bus bars of the interdigital transducer, the two bus bars have a crossing area between them, the crossing area includes a middle area and edge areas located at both ends of the middle area; in the arrangement direction of each electrode finger of the interdigital transducer, the crossing area is an area in which each electrode finger overlaps with each other; the electrode finger includes a widened part located in the edge area;

[0029] An auxiliary structure is located in the edge area;

[0030] The widened part includes a fourth area, a fifth area and a sixth area, in the length extension direction of the electrode finger, the fourth area and the sixth area are respectively located on the two sides away from the fifth area;

[0031] In the same edge area, the projection of the auxiliary structure in the top view direction overlaps with the fifth area along the length extension direction of the electrode finger.

[0032] Embodiments of the present application also provide a filter comprising the surface acoustic wave device according to any one of the above.

[0033] Embodiments of the present application also provide a radio frequency front end module comprising the surface acoustic wave device according to any one of the above.

[0034] The surface acoustic wave device, the filter and the radio frequency front-end module provided by the embodiments of the present application have the following advantages: the projection of the widened part and the auxiliary structure in the top view direction extends at least partially in the length direction of the electrode finger at the same edge area of the interdigital transducer of the surface acoustic wave device; the acoustic impedance of the area provided with the widened part is different from the acoustic impedance of the area provided with the auxiliary structure in the same edge area, so as to adjust the acoustic impedance of the edge area, so that the acoustic impedance of the area provided with the widened part is different from the acoustic impedance of the area provided with the auxiliary structure, thereby making the surface acoustic wave device better inhibit the high-order transverse mode and better inhibit the low-order transverse mode, reducing the adverse effects of the transverse mode on the surface acoustic wave device, and effectively preventing energy leakage. BRIEF DESCRIPTION OF DRAWINGS

[0035] 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. 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.

[0036] Fig. 1 is a structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0037] Fig. 2 is a structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0038] Fig. 3 is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0039] Fig. 4 is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0040] Fig. 5 is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0041] Fig. 6 is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0042] Fig. 7 is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0043] Fig. 8 is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0044] Fig. 9 is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0045] Fig. 10 is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0046] Fig. 11 is a schematic diagram of a partial structure of a surface acoustic wave device according to an embodiment of the present application;

[0047] Figs. 12(a) and 12(b) are schematic diagrams of partial structures of surface acoustic wave devices according to different embodiments of the present application, respectively;

[0048] Figs. 12(c)-(f) are schematic diagrams of structures of widening portions according to different embodiments of the present application, respectively;

[0049] Fig. 13 is a schematic diagram of a partial structure of a surface acoustic wave device according to an embodiment of the present application;

[0050] Fig. 14 is a graph of an admittance curve of a surface acoustic wave device of Comparative Example 1;

[0051] Fig. 15 is a graph of an admittance curve of a surface acoustic wave device of Comparative Example 2;

[0052] Fig. 16 is a graph of an admittance curve of a surface acoustic wave device according to an embodiment of the present application;

[0053] Fig. 17 is a graph of a comparison of real parts of admittances of a surface acoustic wave device according to an embodiment of the present application and a surface acoustic wave device of a comparative example. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of the present application.

[0055] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate the orientation or positional relationship shown in the drawings, and are merely used for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are used for the purpose of description only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0056] Referring to FIG. 1 and FIG. 2, the embodiment of the present application provides a surface acoustic wave device 1000, which comprises a piezoelectric substrate 100 and an interdigital transducer 200, and the interdigital transducer 200 is arranged on the piezoelectric substrate 100. The interdigital transducer 200 and the piezoelectric substrate 100 can cooperate to convert an electrical signal into an acoustic wave or convert an acoustic wave into an electrical signal. Exemplarily, the surface acoustic wave device 1000 can further comprise a reflective structure 300, and the reflective structure 300 can be arranged on two opposite sides of the interdigital transducer 200. Specifically, in the direction of acoustic wave propagation, the reflective structure 300 is arranged on two opposite sides of the interdigital transducer 200. The reflective structure 300 is used to reflect the acoustic wave and limit the acoustic wave in the area where the interdigital transducer 200 is located.

[0057] Exemplarily, the surface acoustic wave device 1000 can comprise 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.

[0058] In some embodiments, the material of the piezoelectric substrate 100 can specifically comprise at least one of quartz, aluminum nitride, sapphire, LN (lithium niobate, LiNbO3), LT (lithium tantalate, LiTaO3), or the like, which is not specifically limited herein.

[0059] In some embodiments, the material of the interdigital transducer 200 can be a single metal material or a composite or alloy material of different metals. Optionally, the material of the interdigital transducer 200 can be one of aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, or a composite or alloy thereof.

[0060] Referring to FIG. 2 and FIG. 3, the interdigital transducer 200 comprises bus bars 10 and electrode fingers 20. The number of the bus bars 10 comprises two, and in the arrangement direction of the two bus bars 10 of the interdigital transducer 200, the two bus bars 10 have a crossing area A1 therebetween, and the crossing area A1 comprises a middle area A11 and edge areas A12 located on both sides of the middle area A11. In the arrangement direction of each electrode finger 20 of the interdigital transducer 200, the crossing area A1 is an area where each electrode finger 20 overlaps with each other.

[0061] Exemplarily, the bus bars 10 and the electrode fingers 20 can be prepared simultaneously in one process, or can be prepared in different processes, which is not specifically limited herein.

[0062] Referring to FIG. 3, in some embodiments, the two bus bars 10 are a first bus bar 11 and a second bus bar 12, which are arranged along a first direction on the piezoelectric substrate 100, and the first bus bar 11 and the second bus bar 12 are respectively connected with a plurality of electrode fingers 20. Each electrode finger 20 includes a first electrode finger 201 and a second electrode finger 202, the first electrode finger 201 is connected with the first bus bar 11, and the second electrode finger 202 is connected with the second bus bar 12. The first electrode finger 201 and the second electrode finger 202 are arranged along a second direction. The first direction is perpendicular to the second direction. For example, the first electrode finger 201 and the second electrode finger 202 are arranged along the second direction in an alternating manner. For example, the first direction is perpendicular to the second direction in the plane of the piezoelectric substrate 100. For example, the first direction is the arrangement direction of the two bus bars 10 or the length extension direction of the electrode fingers 20, and the second direction is the sound wave propagation direction or the arrangement direction of the electrode fingers 20. For example, the first direction or the arrangement direction of the two bus bars 10 is shown as the X direction in FIG. 3, and the second direction or the arrangement direction of the electrode fingers 20 is shown as the Y direction in FIG. 3.

[0063] For example, the top view direction in the embodiment is perpendicular to the first direction and the second direction. For example, the interdigital transducer 200 is arranged on the upper surface of the piezoelectric substrate 100, and the "top view direction" refers to the direction of viewing the piezoelectric substrate 100 from top to bottom and perpendicular to the upper surface of the piezoelectric substrate 100. The meaning of the term "top view direction" is the same in each embodiment, and will not be repeated in subsequent embodiments.

[0064] In other embodiments, the length direction of the bus bar 10 can also intersect the second direction, as long as it is not parallel to the first direction. The length direction of each electrode finger 20 can be parallel to the first direction.

[0065] Referring to FIG. 3, for example, each electrode finger 20 is arranged between the first bus bar 11 and the second bus bar 12. In the first direction, one end of the first electrode finger 201 is connected with the first bus bar 11, and the other end of the first electrode finger 201 is arranged away from the second bus bar 12. One end of the second electrode finger 202 is connected with the second bus bar 12, and the other end of the second electrode finger 202 is arranged away from the first bus bar 11. It can be understood that the end of each first electrode finger 201 close to the second bus bar 12 can be flush or not flush, and the end of each second electrode finger 202 close to the first bus bar 11 can be flush or not flush. In the second direction, the widths of the electrode fingers 20 can be the same or different. In the second direction, the widths of the accelerating portions 21 of the electrode fingers 20 can be the same or different.

[0066] Referring to FIG. 3, the intersection region A1 is formed between the two bus bars 10, and the gap region B1 is located at both ends of the intersection region A1 in the first direction. It can be understood that the region between the first electrode finger 201 and the second bus bar 12 and the region between the second electrode finger 202 and the first bus bar 11 are both gap regions B1.

[0067] Referring to FIG. 3, in some embodiments, the surface acoustic wave device 1000 further comprises an auxiliary structure 400 located in the edge region A12; the electrode finger 20 comprises a widened portion 21 located in the edge region A12. In the same edge region A12, the projection of the widened portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode finger 20, and the acoustic impedance of the region provided with the widened portion 21 is different from the acoustic impedance of the region provided with the auxiliary structure 400.

[0068] In the same edge region A12, the acoustic impedance of the region provided with the widened portion 21 is different from the acoustic impedance of the region provided with the auxiliary structure 400, and by at least partially staggering the projection of the widened portion 21 and the auxiliary structure 400 in the top view direction along the length extension direction of the electrode finger 20 in the same edge region A12, the acoustic impedance of the edge region A12 is adjusted so that the acoustic impedance of the region provided with the widened portion 21 is different from the acoustic impedance of the region provided with the auxiliary structure 400, thereby enabling the surface acoustic wave device 1000 to better suppress both high-order transverse modes and low-order transverse modes, effectively suppressing transverse modes of the surface acoustic wave device 1000, and minimizing the adverse effects of transverse modes on the surface acoustic wave device 1000, effectively preventing energy leakage.

[0069] In some embodiments, in the intersection region A1, the average of the acoustic impedance of the region provided with the widened portion 21 and the acoustic impedance of the region provided with the auxiliary structure 400 is E; E is less than the acoustic impedance of the middle region A11. Illustratively, in the same edge region A12, the projection of the widened portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode finger 20, so that in the same edge region A12, the acoustic impedance of the region provided with the widened portion 21 is different from the acoustic impedance of the region provided with the auxiliary structure 400; and the average of the acoustic impedance of the two structures E is less than the acoustic impedance of the middle region A11, which can ensure that the surface acoustic wave device 1000 can effectively suppress high-order transverse modes and low-order transverse modes, thereby effectively suppressing transverse modes and having a good transverse mode suppression effect.

[0070] In some embodiments, the acoustic impedance of the region provided with the auxiliary structure 400 is smaller than the acoustic impedance of the region not provided with the auxiliary structure 400 and the widened portion 21 within the same edge region A12. Exemplarily, the projection of the widened portion 21 and the auxiliary structure 400 in the top-down direction is arranged at least partially staggered along the length extension direction of the electrode finger 20 within the same edge region A12, so that the acoustic impedance of the region provided with the widened portion 21 is different from the acoustic impedance of the region provided with the auxiliary structure 400 within the same edge region A12. When the projection of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 is arranged spaced apart along the length extension direction of the electrode finger 20 within the same edge region A12, or there is a region not provided with the widened portion 21 and the auxiliary structure 400 in addition to the region provided with the widened portion 21 or the auxiliary structure 400, the acoustic impedance of the region provided with the auxiliary structure 400 is smaller than the acoustic impedance of the region not provided with the auxiliary structure 400 and the widened portion 21, a larger acoustic impedance difference can be formed in the edge region A12, and a higher resonant frequency of the transverse mode of the surface acoustic wave device can be suppressed, and a filter in a high frequency band can be implemented.

[0071] In some embodiments, the acoustic impedance of the region provided with the auxiliary structure 400 is smaller than the acoustic impedance of the region not provided with the auxiliary structure 400 and the widened portion 21 within the same edge region A12. Exemplarily, the projection of the widened portion 21 and the auxiliary structure 400 in the top-down direction is arranged at least partially staggered along the length extension direction of the electrode finger 20 within the same edge region A12, so that the acoustic impedance of the region provided with the widened portion 21 is different from the acoustic impedance of the region provided with the auxiliary structure 400 within the same edge region A12. When the projection of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 is arranged spaced apart along the length extension direction of the electrode finger 20 within the same edge region A12, or there is a region not provided with the widened portion 21 and the auxiliary structure 400 in addition to the region provided with the widened portion 21 or the auxiliary structure 400, the acoustic impedance of the region provided with the auxiliary structure 400 is smaller than the acoustic impedance of the region not provided with the auxiliary structure 400 and the widened portion 21, a larger acoustic impedance difference can be formed in the edge region A12, and a higher resonant frequency of the transverse mode of the surface acoustic wave device can be suppressed, and a filter in a high frequency band can be implemented.

[0072] In some embodiments, the acoustic impedance of the region provided with the auxiliary structure 400 is smaller than the acoustic impedance of the region provided with the widened portion 21. The acoustic impedance of the region provided with the auxiliary structure 400 is lower than the acoustic impedance of the region provided with the widened portion 21, so that a high-low fluctuation acoustic impedance distribution can be formed in the edge region A12, a larger acoustic impedance difference can be achieved, a higher resonant frequency of the transverse mode of the surface acoustic wave device can be suppressed, and a filter in a high frequency band can be implemented.

[0073] In some embodiments, the acoustic impedance of one of the widening 21 and the appendage structure 400 closer to the middle region Al 1 is greater than the acoustic impedance of the other farther from the middle region Al 1, so that a high-low undulating acoustic impedance distribution can be formed in the edge region A12 to better suppress the high-order transverse mode and the low-order transverse mode, and improve the performance of the surface acoustic wave device. For example, referring to FIG. 3, the widening 21 is closer to the middle region Al 1 than the appendage structure 400 in the first direction. By adjusting the width of the widening 21 and the material and thickness of the appendage structure 400, the acoustic impedance of the region F1 provided with the widening 21 is greater than the acoustic impedance of the region F2 provided with the appendage structure 400. In addition, the acoustic impedance of the middle region Al 1 is greater than the acoustic impedance of the region F1 provided with the widening 21, and the acoustic impedance of the gap region Bl is greater than the acoustic impedance of the region F2 provided with the appendage structure 400, thereby effectively suppressing the low-order transverse mode and the high-order transverse mode, and effectively improving the performance of the surface acoustic wave device 1000. Exemplarily, when the widening 21 is closer to the middle region Al 1 than the appendage structure 400 in the first direction, the edge region A12 can be the maximum spacing region between the widening 21 of the electrode finger 20 and the finger end portion of the electrode finger 20 in the first direction, such as A12 shown in FIG. 3.

[0074] For another example, the appendage structure 400 is closer to the middle region Al 1 than the widening 21 in the first direction, such as FIG. 7. Exemplarily, within the same edge region A12, the widening 21 is adjacent to the appendage structure 400, the widening 21 is farther from the middle region Al 1 than the appendage structure 400, the acoustic impedance of the region provided with the appendage structure 400 is greater than the acoustic impedance of the region provided with the widening 21, the acoustic impedance of the middle region Al 1 is greater than the acoustic impedance of the region provided with the appendage structure 400, and the acoustic impedance of the gap region Bl is greater than the acoustic impedance of the region provided with the widening 21, thereby effectively suppressing the low-order transverse mode and the high-order transverse mode, and effectively improving the performance of the surface acoustic wave device 1000. Exemplarily, when the appendage structure 400 is closer to the middle region Al 1 than the widening 21 in the first direction, the edge region A12 can be the region (including the region corresponding to the appendage structure 400) in the first direction between the projection of the interdigital transducer 200 in the plane and the bus bar 11.

[0075] Exemplarily, in the arrangement direction of the two bus bars 10, the projection of the auxiliary structure 400 in the top-down direction can cover the gap region B1. In some embodiments, in the top-down direction, the electrode fingers 20 can also be appropriately exposed from the auxiliary structure 400 in the arrangement direction of the two bus bars 10. Exemplarily, the length of the exposed part is much smaller than the length of the part covered by the auxiliary structure 400. Exemplarily, in the arrangement direction of the two bus bars 10, the projection of the auxiliary structure 400 in the top-down direction is flush with or closer to the middle region A11 than the end of the electrode finger 20 away from the connected bus bar 10.

[0076] It can be understood that the length and / or width of the widened part 21 can be adjusted to adjust the acoustic impedance of the region where the widened part 21 is located, in cooperation with the auxiliary structure 400, to achieve good high-order transverse mode suppression effect and good low-order transverse mode suppression effect. Similarly, the length of the auxiliary structure 400 in the arrangement direction of the two bus bars 10 and the thickness of the auxiliary structure 400 in the top-down direction can be designed in at least one of the ways to cooperate with the widened part 21 to achieve good high-order transverse mode suppression effect and good low-order transverse mode suppression effect. Referring to FIG. 3, exemplarily, in the arrangement direction of the bus bars 10, the middle region A11 is flanked by two edge regions A12. The widened part 21 at one of the edge regions A12 and the widened part 21 at the other edge region A12 can be arranged in axial symmetry or in non-axial symmetry. The auxiliary structure 400 at one of the edge regions A12 and the auxiliary structure 400 at the other edge region A12 can be arranged in axial symmetry or in non-axial symmetry. For example, the size of at least one of the widened part 21 and the auxiliary structure 400 on the two sides of the same electrode finger 20 can be different, or the position of at least one of the widened part 21 and the auxiliary structure 400 on the two sides of the same electrode finger 20 can be different. Exemplarily, the shape of the cross region A1 (i.e., the aperture of the interdigital transducer 200) can be a rectangle or a wave shape or any other suitable shape. The shape of the cross region A1 can be non-rectangular (i.e., other than a rectangle) by at least one of the following ways: adjusting at least one of the position and shape of the widened part 21 and / or the auxiliary structure 400 at the edge region A12; designing the middle region A11 to be other than a rectangle.

[0077] Referring to FIG. 4, in some embodiments, the length of the widened part 21 in the arrangement direction of the two bus bars 10 is L2, and 0 < L2 < 2.8λ, where λ is the period of the electrode finger 20. For example, L2 is 0.1λ, 0.5λ, 1λ, 1.5λ, 2λ, 2.7λ or any other suitable value within the range of 0-2.8λ. L2 is within the range, which is easy and convenient to process, has a high yield of the processed products, and can effectively suppress high-order transverse modes and low-order transverse modes.

[0078] In some embodiments, the thickness of the widened portion 21 is equal to the thickness of the electrode fingers 20 located in the middle region A11. In this way, the widened portion 21 and the electrode fingers 20 can be processed in the same process, and the processing of the surface acoustic wave device 1000 is simple, easy, and has high processing efficiency. In other embodiments, the widened portion 21 can also be processed by a different processing technology from the electrode fingers 20 located in the middle region A11. The thickness of the widened portion 21 can also be different from the thickness of the electrode fingers 20 located in the middle region A11.

[0079] Please refer to FIG. 4. In some embodiments, the width of the auxiliary structure 400 in the arrangement direction of each electrode finger 20 is W1, and the width of the electrode finger 20 in the arrangement direction of each electrode finger 20 is W3, and W1≥W3 / 2. In this way, the high-order transverse mode and the low-order transverse mode can be effectively suppressed, and the processing is easy and convenient.

[0080] Exemplarily, the length of the widened portion 21 in the arrangement direction of the two busbars 10 is L2, 0 < L2 < 2.8λ, where λ is the period of the electrode finger 20; the width of the auxiliary structure 400 in the arrangement direction of each electrode finger 20 is W1, and the width of the electrode finger 20 in the arrangement direction of each electrode finger 20 is W3, and W1≥W3 / 2. In this way, the high-order transverse mode and the low-order transverse mode can be more effectively suppressed; the processing of the surface acoustic wave device 1000 is easier and more convenient.

[0081] Please refer to FIG. 4. In some embodiments, the length of the auxiliary structure 400 in the arrangement direction of the two busbars 10 is L1, 0.01λ < L1 < 2.6λ, where λ is the period of the electrode finger 20. For example, L1 is 0.02λ, 0.5λ, 1λ, 1.5λ, 2λ, 2.5λ or any other suitable value within 0.01λ - 2.6λ. When L1 is within this range, the processing is easy, the qualified rate of the processed product is high, and the high-order transverse mode and the low-order transverse mode can be effectively suppressed.

[0082] In some embodiments, the thickness of the auxiliary structure 400 is H1, 0.002λ < H1 < 2λ, where λ is the period of the electrode finger 20. For example, H1 is 0.003λ, 0.01λ, 0.5λ, 1λ, 1.5λ, 1.9λ or any other suitable value within 0.002λ - 2λ. When H1 is within this range, the processing is easy and convenient, the qualified rate of the processed product is high, and the high-order transverse mode and the low-order transverse mode can be effectively suppressed. Here, the thickness of the auxiliary structure 400 refers to the thickness of the auxiliary structure 400 in the top view direction. Exemplarily, 0.01λ < L1 < 2.6λ, 0.002λ < H1 < 2λ, so that the processing of the surface acoustic wave device 1000 is easier and more convenient, and the high-order transverse mode and the low-order transverse mode can be fully and effectively suppressed.

[0083] Exemplarily, the length of the auxiliary structure 400 along the arrangement direction of the two busbars 10 is L1, where 0.01λ < L1 < 2.6λ; the thickness of the auxiliary structure 400 is H1, where 0.002λ < H1 < 2λ, and λ is the period of the electrode fingers 20. In this way, it is possible to effectively suppress the high-order transverse mode and the low-order transverse mode as much as possible, and further make the processing of the surface acoustic wave device 1000 easier and more convenient.

[0084] Please refer to FIG. 4. In some embodiments, within the same edge region A12, the width of the widened portion 21 along the arrangement direction of the electrode fingers 20 is W2, the width of the electrode finger 20 along the arrangement direction of the electrode fingers 20 is W3, and the center-to-center distance between two adjacent electrode fingers 20 is P3, where W3 ≤ W2 < (2P3 - W3). In this way, it is possible to effectively suppress the high-order transverse mode and the low-order transverse mode, and the processing is easy and convenient.

[0085] Exemplarily, the length of the widened portion 21 along the arrangement direction of the two busbars 10 is L2, where 0 < L2 < 2.8λ, and λ is the period of the electrode fingers 20; the width of the auxiliary structure 400 along the arrangement direction of the electrode fingers 20 is W1, the width of the electrode finger 20 along the arrangement direction of the electrode fingers 20 is W3, and W1 ≥ W3 / 2; the length of the auxiliary structure 400 along the arrangement direction of the two busbars 10 is L1, where 0.01λ < L1 < 2.6λ; the thickness of the auxiliary structure 400 is H1, where 0.002λ < H1 < 2λ. In this way, it is possible to effectively suppress the high-order transverse mode and the low-order transverse mode to the greatest extent, and further make the processing of the surface acoustic wave device 1000 easier and more convenient.

[0086] Please refer to FIG. 3. In some embodiments, within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction are adjacent along the length extension direction of the electrode finger 20. That is to say, within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction are arranged adjacent to each other in the first direction and the projections of the two are in contact in the first direction. In this way, the surface acoustic wave device 1000 can not only better suppress the high-order transverse mode, but also better suppress the low-order transverse mode, so as to better suppress the transverse mode; and it can save materials and reduce costs. It can be understood that within the reasonable processing error range, within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction are adjacent along the length extension direction of the electrode finger 20.

[0087] Referring to Figure 5, in some other embodiments, within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction are spaced apart along the length extension direction of the electrode finger 20, thereby allowing for a certain process error tolerance, strong operability, low process cost, and improved product yield; and can better suppress the abutment lateral mode and higher-order lateral mode.

[0088] Referring to Figure 6, in some embodiments, within the same edge region A12, the projections of the widened portion 21 corresponding to the same electrode finger 20 and the auxiliary structure 400 in the top view direction partially overlap along the length extension direction of the electrode finger 20. This allows for a certain degree of process tolerance, strong operability, low process cost, and improved product yield; and can better suppress the contact transverse mode and higher-order transverse modes. For example, within the same edge region A12, the acoustic impedance of the area where the projections of the auxiliary structure 400 and the widened portion 21 overlap in the top view direction is less than the acoustic impedance of the remaining portion. This acoustic impedance distribution can better suppress higher-order and lower-order transverse modes, thereby suppressing transverse modes first during the sound wave leakage from the intersection region A1 to the gap region B1. For example, referring to Figure 6, the lengths by which the widened portion 21 and the auxiliary structure 400 are staggered are much greater than the length of their overlapping portion. The lengths by which the widened portion 21 and the auxiliary structure 400 are staggered refer to the lengths of the widened portion 21 and the auxiliary structure 400 along the length extension direction of the electrode finger 20.

[0089] Referring to Figure 5, in some embodiments, within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction are spaced apart by a predetermined distance L3 along the length extension direction of the electrode finger 20, where L3 < 2.6λ, and λ is the period of the electrode finger 20. For example, referring to Figure 5, within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction are spaced apart along the length extension direction of the electrode finger 20, and the distance between them is L3, where L3 < 2.6λ. In this way, while ensuring good suppression of higher-order and lower-order transverse modes, the size of the surface acoustic wave device 1000 along the length extension direction of the electrode finger 20 can be minimized, which is beneficial for product miniaturization and cost reduction. Exemplarily, the size of the widened portion 21 along the length extension direction of the electrode finger 20 is greater than L3, and the size of the auxiliary structure 400 along the length extension direction of the electrode finger 20 is greater than L3.

[0090] Referring to Figure 6, in some embodiments, within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction overlap by a preset distance L4, where L4 < 2.6λ, and λ is the period of the electrode finger 20. As another example, referring to Figure 6, within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction partially overlap along the length extension direction of the electrode finger 20, and the overlap distance is L4, where L4 < 2.6λ. This allows for a reduction in the dimensions of the widened portion 21 and the auxiliary structure 400 along the length extension direction of the electrode finger 20 while ensuring good suppression of higher-order and lower-order lateral modes, which is beneficial for product miniaturization and cost reduction. For example, within the same edge region A12, the widened portion 21 includes a first offset region. The first offset region corresponding to the same electrode finger 20 is adjacent to and offset from the projection of the auxiliary structure 400 in the top view direction. The dimension of the first offset region along the length extension direction of the electrode finger 20 is greater than L4. The auxiliary structure 400 includes a second offset region. The second offset region corresponding to the same electrode finger 20 is adjacent to and offset from the projection of the widened portion 21 in the top view direction. The dimension of the second offset region along the length extension direction of the electrode finger 20 is greater than L4.

[0091] Referring to Figure 3, in some embodiments, within the same edge region A12, the widened portion 21 is closer to the central region A11 than at least a portion of the auxiliary structure 400, in order to achieve both ease of fabrication, good suppression of higher-order lateral modes, and good suppression of lower-order modes. For example, within the same edge region A12, the projections of the widened portion 21 corresponding to the same electrode finger 20 and the auxiliary structure 400 in the top view direction are adjacent along the length extension direction of the electrode finger 20, with the widened portion 21 being closer to the central region A11 than the auxiliary structure 400. For example, within the same edge region A12, the widened portion 21 is closer to the central region A11 than the auxiliary structure 400. This results in a structure where the acoustic impedance of the region with the widened portion 21 is greater than that of the region with the auxiliary structure 400. This allows for a wider range of adjustment in the acoustic impedance difference between the two locations. Furthermore, while improving the suppression of higher-order transverse modes and the suppression of adjacent transverse modes, the width of the widened portion 21 (located inside the edge region A12) is made relatively small, minimizing its impact on the device's resonant frequency. This allows for a smaller spacing between the electrode fingers 20, making the device suitable for higher-frequency filters. Therefore, better suppression of both higher-order and lower-order transverse modes can be achieved at higher frequencies. Understandably, the widened portion 21 is closer to the intermediate region A11 than at least a portion of the auxiliary structure 400, including at least one of the following situations: Situation a), within the same edge region A12, the projections of the widened portion 21 corresponding to the same electrode finger 20 and the auxiliary structure 400 in the top view direction partially overlap along the length extension direction of the electrode finger 20, and the widened portion 21 is closer to the intermediate region A11 than the portion of the auxiliary structure 400 that does not overlap with the widened portion 21. Situation b), within the same edge region A12, the projections of the widened portion 21 corresponding to the same electrode finger 20 and the auxiliary structure 400 in the top view direction are adjacent or spaced apart along the length extension direction of the electrode finger 20, and the widened portion 21 is closer to the intermediate region A11 than the auxiliary structure 400.

[0092] Exemplarily, within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction are adjacent along the length extension direction of the electrode finger 20. The widened portion 21 is closer to the middle region A11 than the auxiliary structure 400. The length of the auxiliary structure 400 in the arrangement direction of the two bus bars 10 is L1, where 0.01λ < L1 < 2.6λ; the thickness of the auxiliary structure 400 is H1, where 0.002λ < H1 < 2λ; the length of the widened portion 21 in the arrangement direction of the two bus bars 10 is L2, where 0 < L2 < 2.8λ; the width of the widened portion 21 in the arrangement direction of each electrode finger 20 is W2, the width of the electrode finger 20 in the arrangement direction of each electrode finger 20 is W3, and the center-to-center distance between two adjacent electrode fingers 20 is P3, where W3 ≤ W2 < (2P3 / 2 - W3). In this way, the processing of the surface acoustic wave device 1000 can be made easy and convenient, and the high-order lateral modes and low-order lateral modes can be suppressed as fully as possible.

[0093] Please refer to FIG. 7. In some embodiments, within the same edge region A12, the widened portion 21 is farther from the middle region A11 than at least a part of the auxiliary structure 400. Exemplarily, within the same edge region A12, the widened portion 21 is adjacent to the auxiliary structure 400, and the widened portion 21 is farther from the middle region A11 than the auxiliary structure 400.

[0094] Please refer to FIG. 8. In some embodiments, the auxiliary structure 400 includes a plurality of auxiliary blocks 401, which are sequentially arranged at intervals in the arrangement direction of each electrode finger 20; the projection of each electrode finger 20 and an auxiliary block 401 at least partially overlap in the top view direction. That is, along the arrangement direction of each electrode finger 20, the auxiliary structure 400 is arranged discontinuously. In this way, on the basis of ensuring good high-order transverse mode suppression effect and low-order transverse mode suppression effect, the auxiliary structure 400 uses less material, can reduce the weight of the auxiliary structure 400 to reduce the weight of the surface acoustic wave device 1000, which is beneficial to achieving product lightweight and cost reduction. It can be understood that the overlapping areas of the projections of each electrode finger 20 and the corresponding auxiliary block 401 in the top view direction can be the same or different. Their sizes in the arrangement direction of each electrode finger 20 can be the same or different. For the same auxiliary structure 400, the lengths of the included auxiliary blocks 401 in the arrangement direction of the two bus bars 10 can be the same or different; the widths of the included auxiliary blocks 401 in the arrangement direction of each electrode finger 20 can be the same or different; the thicknesses of the included auxiliary blocks 401 can be the same or different. Exemplarily, the lengths, widths and thicknesses of each auxiliary block 401 are convenient for being manufactured in the same process, reducing the process cost. In some embodiments, each auxiliary block 401 overlaps with the corresponding electrode finger 20 in the arrangement direction of each electrode finger 20.

[0095] Referring to Figure 3, in some embodiments, the projection of the auxiliary structure 400 and each electrode finger 20 in the top view direction overlaps with the arrangement direction of each electrode finger 20, and also overlaps with the projection of the gap between any two adjacent electrode fingers 20 in the top view direction. That is, the auxiliary structure 400 is continuously and uninterruptedly arranged along the arrangement direction of each electrode finger 20. In this way, while ensuring good high-order transverse mode suppression effect and low-order transverse mode suppression effect, the auxiliary structure 400 is simple and convenient to process.

[0096] Referring to Figure 9, in some embodiments, the auxiliary structure 400 is located on the side of the interdigital transducer 200 facing the piezoelectric substrate 100, facilitating the fabrication of the auxiliary structure 400 in a single process, reducing process steps and lowering costs. Referring to Figure 10, in some embodiments, the auxiliary structure 400 is located on the side of the interdigital transducer 200 away from the piezoelectric substrate 100. This facilitates the fabrication of the auxiliary structure 400 in a single process, reducing process steps and lowering costs. Furthermore, with the auxiliary structure 400 located on the side of the interdigital transducer 200 away from the piezoelectric substrate 100, the fabrication of both the auxiliary structure 400 and the interdigital transducer 200 is easy and convenient, and the fabrication of the surface acoustic wave device 1000 is simple and convenient. In still other embodiments, one portion of the auxiliary structure 400 is located on the side of the interdigital transducer 200 facing the piezoelectric substrate 100, and another portion of the auxiliary structure 400 is located on the side of the interdigital transducer 200 away from the piezoelectric substrate 100.

[0097] Referring to Figure 10, in some embodiments, the auxiliary structure 400 is fitted to the electrode finger 20 in a top view. Referring to Figure 11, in some embodiments, the auxiliary structure 400 and the electrode finger 20 are spaced apart in a top view, which is beneficial for balancing ease of processing and product reliability.

[0098] The shapes of the auxiliary structure 400, auxiliary block 401, and / or widening portion 21 can be designed according to actual needs and are not limited here. For example, the auxiliary structure 400 can be a strip shape as shown in Figure 4; or a shape as shown in Figure 12(a) or 12(b); or any other suitable regular or irregular shape, etc. Similarly, the shape of the widening portion 21 can be a square shape as shown in Figure 4; or any shape shown in Figures 12(c)-12(f); or any other suitable regular or irregular shape, etc.

[0099] For example, the widened portion 21 can be fabricated in the same process as the electrode finger 20, while the auxiliary structure 400 is fabricated in another process. By fabricating the auxiliary structure 400 in the same process, this embodiment can reduce the number of fabrication steps for the surface acoustic wave device 1000 compared to a scheme that achieves acoustic impedance difference by fabricating the auxiliary structure 400 in two different processes.

[0100] The auxiliary structure 400 can be a single metal or a composite or alloy of different metals. For example, the material of the auxiliary structure 400 can be one of molybdenum, tungsten, ruthenium, gold, magnesium, aluminum, copper, chromium, titanium, osmium, iridium, or a composite of the above metals or their alloys. Of course, the material of the auxiliary structure 400 can also be a dielectric, such as tantalum oxide. In some embodiments, the auxiliary structure 400 is a conductive structure or a non-conductive structure. A conductive structure can include a structure made of a conductive metal. A non-conductive structure can be made of silicon dioxide or any other suitable material.

[0101] In some embodiments, the auxiliary structure 400 is a conductive structure, including auxiliary blocks 401. In the arrangement direction of the electrode fingers 20, the auxiliary blocks 401 are arranged sequentially at intervals; in the top view, each electrode finger 20 is attached to one auxiliary block 401. The surface acoustic wave device 1000 also includes a dielectric layer 500 (see Figure 11), which is disposed on the piezoelectric substrate 100 and covers the interdigital transducer 200 and the auxiliary structure 400. This structure of the surface acoustic wave device 1000 has a reasonable structural design, is easy and convenient to manufacture, and has good transverse mode suppression effect. For example, the auxiliary structure 400 is a conductive structure; in the top view direction, each electrode finger 20 is attached to an auxiliary block 401. The electrode finger 20 and the auxiliary block 401 can be manufactured in the same process. For example, both the electrode finger 20 and the auxiliary block 401 are manufactured using a coating process. The electrode finger 20 and the auxiliary block 401 do not need to be manufactured using two different processes, which makes the fabrication of the surface acoustic wave device 1000 simple, convenient and easy.

[0102] In some embodiments, the auxiliary structure 400 is a non-conductive structure; in the top view, the auxiliary structure 400 is attached to the interdigital transducer 200. For example, the auxiliary structure 400 overlaps with the projection of each electrode finger 20 in the top view, and also overlaps with the projection of the gap between any two adjacent electrode fingers 20 in the top view; that is, the auxiliary structure 400 is a continuous, uninterrupted strip structure. Since the auxiliary structure 400 is attached to the interdigital transducer 200 in the top view, the auxiliary structure 400 is a non-conductive structure.

[0103] In other embodiments, the auxiliary structure 400 can be either a conductive or non-conductive structure. For example, in a top-view orientation, a dielectric layer 500 is provided between the auxiliary structure 400 and the interdigital transducer 200; the auxiliary structure 400 is a non-conductive structure. This type of surface acoustic wave device 1000 is easy, convenient, and simple to manufacture, and has good suppression effects on higher-order and lower-order transverse modes. Exemplarily, in a top-view orientation, a dielectric layer 500 is provided between the auxiliary structure 400 and the interdigital transducer 200, and the auxiliary structure 400 and the interdigital transducer 200 are fabricated separately. For example, the auxiliary structure 400 is fabricated using an etching or stripping process, and the interdigital transducer 200 is fabricated using a coating process. The non-conductive structure of the auxiliary structure 400 facilitates the manufacture of the auxiliary structure 400 and / or the interdigital transducer 200, thereby making the fabrication of the surface acoustic wave device 1000 simple, convenient, and easy.

[0104] Referring to Figure 11, in some embodiments, the surface acoustic wave device 1000 further includes a dielectric layer 500 covering the interdigital transducer 200. The dielectric layer 500 is disposed on the side of the electrode fingers 20 facing away from the piezoelectric substrate 100. The dielectric layer 500 can protect the interdigital transducer 200 and / or auxiliary structures 400, etc. Exemplarily, the dielectric layer 500 covers the interdigital transducer 200 and the auxiliary structures 400. The dielectric layer 500 may completely cover the interdigital transducer 200, or it may not completely cover the interdigital transducer 200, for example, only covering the area where the electrode fingers 20 of the interdigital transducer 200 are located, while the busbar 10 is not covered.

[0105] In some embodiments, the dielectric layer 500 is a temperature compensation layer. The temperature compensation layer is used to improve the temperature characteristics of the surface acoustic wave device 1000. The material of the temperature compensation layer can be a dielectric such as silicon oxide, silicon nitride, or silicon oxynitride. Typically, the material of the temperature compensation layer is one of the aforementioned materials, i.e., the temperature compensation layer is a single material. Of course, the material of the temperature compensation layer can also be a mixture of materials, in which case the material can be a mixture of any of the aforementioned materials, or a mixture of one or more of the aforementioned materials with other materials. In other embodiments, the dielectric layer 500 may also include at least one of the following: a frequency modulation layer and a passivation layer. The frequency modulation layer is used to adjust the frequency of the surface acoustic wave device 1000. The material of the frequency modulation layer can be at least one of silicon dioxide, silicon nitride, aluminum nitride, or aluminum oxide. The passivation layer is used to protect the interdigital transducer 200 and / or auxiliary structures 400. The material of the passivation layer can be at least one of silicon dioxide, silicon nitride, aluminum nitride, or aluminum oxide.

[0106] Referring to Figure 11, in some embodiments, the auxiliary structure 400 is disposed on the side of the dielectric layer 500 opposite to the electrode finger 20. Exemplarily, in a top view, at least a portion of the dielectric layer 500 is disposed between the auxiliary structure 400 and the electrode finger 20; that is, the auxiliary structure 400 and the electrode finger 20 are spaced apart in the top view, and the space between the auxiliary structure 400 and the electrode finger 20 is filled with the dielectric layer 500. Referring to Figure 10, in some embodiments, the dielectric layer 500 is disposed on the side of the auxiliary structure 400 opposite to the electrode finger 20; that is, in a top view, the auxiliary structure 400 is disposed between the dielectric layer 500 and the electrode finger 20.

[0107] Referring to Figure 2, in some embodiments, the piezoelectric substrate 100 includes a substrate 101 and a piezoelectric thin film 102 stacked together, with the interdigital transducer 200 disposed on the surface of the piezoelectric thin film 102 facing away from the substrate 101. This improves the Q value of the surface acoustic wave device 1000 and makes it suitable for higher frequency bands of 5G and above. Exemplarily, the substrate 101 may be made of silicon.

[0108] Referring to Figure 13, in some embodiments, the interdigital transducer 200 further includes a pseudo-finger 30, one end of which is connected to one of the busbars 10, and the other end of which is spaced apart from the tip of the electrode finger 20 connected to the other busbar 10. The pseudo-finger 30 can suppress transverse mode interference of the surface acoustic wave device 1000, reduce energy leakage, and thus improve the Q value of the surface acoustic wave device 1000.

[0109] Referring to Figure 13, exemplarily, the number of pseudo-finger 30 includes multiple pseudo-fingers 30, including a first pseudo-finger 31 and a second pseudo-finger 32. One end of the first pseudo-finger 31 is connected to the first busbar 11, and the other end of the first pseudo-finger 31 is spaced apart from the second electrode finger 202 in the arrangement direction of the two busbars 10. One end of the second pseudo-finger 32 is connected to the second busbar 12, and the other end of the second pseudo-finger 32 is spaced apart from the first electrode finger 201 in the arrangement direction of the two busbars 10. The number of first pseudo-fingers 31 and the number of second pseudo-fingers 32 can be designed according to actual needs, such as one or more. Exemplarily, the number of first pseudo-fingers 31 is multiple, and the end of each first pseudo-finger 31 facing away from the first busbar 11 can be flush or not flush, and a first pseudo-finger 31 can be placed between two adjacent first electrode fingers 201. There are multiple second pseudo fingers 32. The end of each second pseudo finger 32 that is away from the second bus bar 12 can be flush or not flush, and a second pseudo finger 32 can be set between two adjacent second electrode fingers 202.

[0110] Understandably, when the surface acoustic wave device 1000 is provided with a first pseudo-finger 31 and a second pseudo-finger 32, the gap region B1 actually refers to the region located between the first pseudo-finger 31 and the second electrode finger 202 in the arrangement direction of the two busbars 10; or, the region located between the second pseudo-finger 32 and the first electrode finger 201.

[0111] As shown in Figures 14-16, the surface acoustic wave device 1000 of this application embodiment is compared with the surface acoustic wave device 1000 of the conventional structure.

[0112] Figure 14 shows the admittance curve of the surface acoustic wave device 1000 in Comparative Example 1, where the surface acoustic wave device 1000 in Comparative Example 1 does not have the widening section 21 and the auxiliary structure 400. In Figure 14, the horizontal axis represents frequency in GHz; the vertical axis represents admittance in dB. As can be seen from Figure 14, the surface acoustic wave device 1000 has a large transverse mode between the resonant point and the anti-resonant point.

[0113] Figure 15 shows the admittance curve of the surface acoustic wave device 1000 in Comparative Example 2, where the surface acoustic wave device 1000 only includes one of the widening section 21 and the auxiliary structure 400. In Figure 15, the horizontal axis represents frequency in GHz, and the vertical axis represents admittance in dB. By adjusting the structural features of the widening section 21 or the auxiliary structure 400, the surface acoustic wave device 1000 in Figure 15 can achieve transverse mode suppression. However, while low-order transverse modes can be suppressed, the suppression effect on high-order transverse modes is not ideal.

[0114] Figure 16 is an admittance curve of a surface acoustic wave device 1000 provided in an embodiment of this application. In Figure 16, the horizontal axis represents frequency in GHz, and the vertical axis represents admittance in dB. Comparing Figure 16 with Figures 14 and 15, it can be seen that this embodiment, by simultaneously providing the widening portion 21 and the additional structure 400, with the widening portion 21 and the additional structure 400 at least partially offset and having different acoustic impedances, can effectively suppress both high-order transverse modes and low-order transverse modes.

[0115] Figure 17 is a comparison of the real admittance curves of a surface acoustic wave (SAW) device 1000 provided in one embodiment of this application and a comparative SAW device 1000. The dashed line represents the real admittance curve of the comparative SAW device 1000, and the solid line represents the real admittance curve of the SAW device 1000 in this embodiment. The comparative example represents the real admittance curve of a related technology with only one acoustic impedance, where adjusting the acoustic impedance results in better transverse mode suppression. In Figure 17, the horizontal axis represents frequency in GHz, and the vertical axis represents the real admittance in dB. As can be seen from the comparison of the solid and dashed lines in Figure 17, the high-order and low-order transverse modes of the SAW device 1000 in this embodiment are effectively suppressed, demonstrating good transverse mode suppression.

[0116] This application embodiment also provides a surface acoustic wave device 1000, including a piezoelectric substrate 100, an interdigital transducer 200, an auxiliary structure 400, and a dielectric layer 500. The interdigital transducer 200 is disposed on the piezoelectric substrate 100. In the arrangement direction of the two busbars 10 of the interdigital transducer 200, a cross region A1 is formed between the two busbars 10. The cross region A1 includes a middle region A11 and edge regions A12 located at both ends of the middle region A11. In the arrangement direction of the electrode fingers 20 of the interdigital transducer 200, the cross region A1 is the region where the electrode fingers 20 overlap. Each electrode finger 20 includes a widened portion 21 located in the edge region A12; at least one of the two edge regions A12 is provided with a widened portion 21 and an auxiliary structure 400. Within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode fingers 20. The auxiliary structure 400 is a conductive structure and includes multiple auxiliary blocks 401. In the arrangement direction of each electrode finger 20, the auxiliary blocks 401 are arranged sequentially at intervals. In the top view direction, each electrode finger 20 is attached to one auxiliary block 401. The dielectric layer 500 is disposed on the piezoelectric substrate 100 and covers the interdigital transducer 200 and the auxiliary structure 400.

[0117] Furthermore, since the surface acoustic wave device 1000 includes an auxiliary structure 400 and a dielectric layer 500, the auxiliary structure 400 is a conductive structure and includes multiple auxiliary blocks 401. In the arrangement direction of the electrode fingers 20, the auxiliary blocks 401 are arranged sequentially at intervals; in the top view, each electrode finger 20 is attached to one auxiliary block 401; the dielectric layer 500 is disposed on the piezoelectric substrate 100 and covers the interdigital transducer 200 and the auxiliary structure 400. Therefore, the surface acoustic wave device 1000 is easy, convenient, and simple to manufacture. The surface acoustic wave device 1000 of this application embodiment has a reasonable structural design, is easy to manufacture, and has good transverse mode suppression effect.

[0118] Exemplarily, one of the two edge regions A12 is provided with a widening portion 21 and an auxiliary structure 400. Exemplarily, both edge regions A12 are provided with a widening portion 21 and an auxiliary structure 400.

[0119] Exemplary, the piezoelectric substrate 100 includes the piezoelectric substrate 100 of any of the above embodiments. The interdigital transducer 200 includes the interdigital transducer 200 of any of the embodiments of this application. The auxiliary structure 400 includes the auxiliary structure 400 of any of the above embodiments. The dielectric layer 500 includes the dielectric layer 500 of any of the above embodiments.

[0120] This application embodiment also provides a surface acoustic wave device 1000, including a piezoelectric substrate 100, an interdigital transducer 200, and an auxiliary structure 400. The interdigital transducer 200 is disposed on the piezoelectric substrate 100. In the arrangement direction of the two busbars 10 of the interdigital transducer 200, there is a cross region A1 between the two busbars 10. The cross region A1 includes a middle region A11 and edge regions A12 located at both ends of the middle region A11. In the arrangement direction of the electrode fingers 20 of the interdigital transducer 200, the cross region A1 is the region where the electrode fingers 20 overlap with each other. The electrode fingers 20 include a widened portion 21 located in the edge region A12, and at least one of the two edge regions A12 is provided with a widened portion 21 and an auxiliary structure 400. Within the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode fingers 20; the auxiliary structure 400 is a non-conductive structure; in the top view direction, a dielectric layer 500 is provided between the auxiliary structure 400 and the interdigital transducer 200.

[0121] In the surface acoustic wave (SAW) device 1000 of the above embodiment, the widened portion 21 and the auxiliary structure 400 are at least partially offset in the projection direction along the length extension direction of the electrode fingers 20 at the same edge region A12 of the interdigital transducer 200 of the SAW device 1000. This adjusts the acoustic impedance of the edge region A12, making the acoustic impedance of the region with the widened portion 21 different from that of the region with the auxiliary structure 400. This allows the SAW device 1000 to effectively suppress both high-order and low-order transverse modes, thereby effectively suppressing the transverse modes of the SAW device 1000, minimizing the adverse effects of transverse modes on the SAW device 1000, and effectively preventing energy leakage. Furthermore, by offsetting the widened portion 21 and the auxiliary structure 400, the SAW device 1000 of this application is less susceptible to the influence of the spacing distance between adjacent electrode fingers 20 along the second direction during device fabrication, and can be used in higher frequency bands. Furthermore, this embodiment can reduce the occurrence of quality problems such as difficulty in processing or easy short circuits due to excessively small spacing between adjacent electrode fingers 20. Compared with two additional structures 400 of different thicknesses, it can reduce the number of processing steps and lower costs. In addition, the solution of achieving the acoustic impedance difference between two regions using two additional structures 400 of different thicknesses requires multiple processing steps. Compared with the solution of achieving the acoustic impedance difference between two regions using two additional structures 400 of different thicknesses, the surface acoustic wave device 1000 of this embodiment can reduce processing steps and lower process costs.

[0122] Furthermore, since the auxiliary structure 400 is a non-conductive structure, and a dielectric layer 500 is provided between the auxiliary structure 400 and the interdigital transducer 200 in the top view direction, the surface acoustic wave device 1000 is easy, convenient, and simple to manufacture. The surface acoustic wave device 1000 of this application embodiment has a reasonable structural design, is easy to manufacture, and has a good transverse mode suppression effect.

[0123] Exemplarily, one of the two edge regions A12 is provided with a widening portion 21 and an auxiliary structure 400. Exemplarily, both edge regions A12 are provided with a widening portion 21 and an auxiliary structure 400.

[0124] Exemplary, the piezoelectric substrate 100 includes the piezoelectric substrate 100 of any of the above embodiments. The interdigital transducer 200 includes the interdigital transducer 200 of any of the embodiments of this application. The auxiliary structure 400 includes the auxiliary structure 400 of any of the above embodiments. The dielectric layer 500 includes the dielectric layer 500 of any of the above embodiments.

[0125] This application embodiment also provides a surface acoustic wave (SAW) device 1000, which includes a piezoelectric substrate 100, an interdigital transducer 200, and an auxiliary structure 300. The interdigital transducer 200 is disposed on the piezoelectric substrate 100. In the arrangement direction of the two busbars 10 of the interdigital transducer 200, a crossover region A1 is formed between the two busbars 10. The crossover region A1 includes a middle region A11 and edge regions A12 located at both ends of the middle region A11. The crossover region A1 is also located in the arrangement direction of the electrode fingers 20 of the interdigital transducer 200. The area is where the electrode fingers 20 overlap; the electrode fingers 20 include a widened portion 21 located in the edge region A12; the auxiliary structure 400 is located in the edge region A12, and the auxiliary structure 400 includes a first region, a second region and a third region. In the length extension direction of the electrode fingers 20, the first region and the third region are located on opposite sides of the second region; wherein, within the same edge region A12, the auxiliary structure 400 covers the widened portion 21, and the projection of the second region in the top view direction overlaps with the widened portion 21 along the length extension direction of the electrode fingers 20.

[0126] In the surface acoustic wave device 1000 of the above embodiment, since the auxiliary structure 400 covers the widened portion 21 within the same edge region A12, and the projection of the second region in the top view direction overlaps with the widened portion 21 along the length extension direction of the electrode finger 20, the acoustic impedance of the edge region A12 can be adjusted so that the acoustic impedance of the region with the widened portion 21 is different from that of the region with the auxiliary structure 400. This allows the surface acoustic wave device 1000 to effectively suppress both high-order transverse modes and low-order transverse modes, thereby effectively suppressing the transverse modes of the surface acoustic wave device 1000, minimizing the adverse effects of transverse modes on the surface acoustic wave device 1000, and effectively preventing energy leakage.

[0127] For example, at least one of the first and third regions has a length in the length extension direction of the electrode finger 20 that is less than the length of the second region in the length extension direction of the electrode finger 20. For example, at least one of the first and third regions has a length in the length extension direction of the electrode finger 20 that is less than 50% of the length of the second region in the length extension direction of the electrode finger 20.

[0128] Exemplary, the piezoelectric substrate 100 includes the piezoelectric substrate 100 of any of the above embodiments. The interdigital transducer 200 includes the interdigital transducer 200 of any of the above embodiments. The widening portion 21 includes the widening portion 21 of any of the above embodiments. The auxiliary structure 400 includes the auxiliary structure 400 of any of the above embodiments.

[0129] For example, the positional relationship of the auxiliary structure 400 can be referred to the previous embodiments, and will not be repeated here.

[0130] This application embodiment also provides a surface acoustic wave device 1000, including a piezoelectric substrate 100, an interdigital transducer 200, and an auxiliary structure 400. The interdigital transducer 200 is disposed on the piezoelectric substrate 100. In the arrangement direction of the two busbars 10 of the interdigital transducer 200, there is a cross region A1 between the two busbars 10. The cross region A1 includes a middle region A11 and edge regions A12 located at both ends of the middle region A11. The cross region A1 is also located in the arrangement direction of the electrode fingers 20 of the interdigital transducer 200. Region A1 is the area where the electrode fingers 20 overlap with each other; the electrode fingers 20 include a widened portion 21 located in the edge region A12; the auxiliary structure 400 is located in the edge region A12; wherein, the widened portion 21 includes a fourth region, a fifth region and a sixth region, and in the length extension direction of the electrode fingers 20, the fourth region and the sixth region are located on opposite sides of the fifth region; within the same edge region A12, the projection of the auxiliary structure 400 in the top view direction overlaps with the fifth region along the length extension direction of the electrode fingers 20.

[0131] In the surface acoustic wave device 1000 of the above embodiment, since the projection of the auxiliary structure 400 in the top view direction overlaps with the fifth region along the length extension direction of the electrode finger 20 within the same edge region A12, the acoustic impedance of the edge region A12 can be adjusted so that the acoustic impedance of the region with the widened portion 21 is different from that of the region with the auxiliary structure 400. As a result, the surface acoustic wave device 1000 can suppress both high-order transverse modes and low-order transverse modes well, thereby effectively suppressing the transverse modes of the surface acoustic wave device 1000, minimizing the adverse effects of transverse modes on the surface acoustic wave device 1000, and effectively preventing energy leakage.

[0132] For example, at least one of the fourth and sixth regions has a length in the length extension direction of the electrode finger 20 that is less than the length of the fifth region in the length extension direction of the electrode finger 20. For example, at least one of the fourth and sixth regions has a length in the length extension direction of the electrode finger 20 that is less than 50% of the length of the fifth region in the length extension direction of the electrode finger 20.

[0133] Exemplarily, the piezoelectric substrate 100 includes the piezoelectric substrate 100 of any of the above embodiments. The interdigital transducer 200 includes the interdigital transducer 200 of any of the above embodiments. The widening portion 21 includes the widening portion 21 of any of the above embodiments. The auxiliary structure 400 includes the auxiliary structure 400 of any of the above embodiments. Exemplarily, the positional relationship between the interdigital transducer 200 and the widening portion 21 can be referred to the previous embodiments, and will not be repeated here. This application embodiment also provides a filter, including the surface acoustic wave device 1000 of any of the above embodiments.

[0134] For example, the filter includes a plurality of surface acoustic wave (SAW) devices 1000, wherein at least one SAW device 1000 includes the SAW device 1000 of any of the above embodiments. The structures of the various SAW devices 1000 may be the same or different, and no limitation is made herein.

[0135] This application also provides a radio frequency front-end module, including the surface acoustic wave device 1000 of any of the above embodiments.

[0136] In some implementations, the radio frequency front-end module can be applied to electronic devices, which may include, but are not limited to, LED panels, tablet computers, laptops, computers, navigators, mobile phones, and electronic watches, etc., which have PCBs. This application does not impose any limitations on this.

[0137] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "mechanical coupling," and "coupling" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, and can refer to the internal communication of two components or the interaction between two components. Mechanical coupling or coupling of two components includes direct coupling and indirect coupling, such as a direct fixed connection or a connection through a transmission mechanism. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0138] In the description of this specification, the reference to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some embodiments," etc., refers to specific method steps, features, structures, materials, or characteristics described in conjunction with embodiments or examples, which are included in at least one embodiment or example of this application. The above descriptions are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A surface acoustic wave device, comprising: a piezoelectric substrate; an interdigital transducer provided on the piezoelectric substrate; a crossover region is provided between two bus bars of the interdigital transducer in the arrangement direction of the bus bars, the crossover region comprises a middle region and edge regions located at both ends of the middle region; wherein, in the arrangement direction of each electrode finger of the interdigital transducer, the crossover region is a region in which each electrode finger overlaps with each other; the electrode finger comprises a widened portion located at the edge region; an auxiliary structure is located at the edge region; wherein, in the same edge region, the projection of the widened portion and the auxiliary structure in the top view direction is at least partially staggered in the length extension direction of the electrode finger, the acoustic impedance of the region provided with the widened portion is different from the acoustic impedance of the region provided with the auxiliary structure.

2. The SAW device of claim 1, wherein, In the crossover region, the average of the acoustic impedance of the region provided with the widened portion and the acoustic impedance of the region provided with the auxiliary structure is E; the E is less than the acoustic impedance of the middle region.

3. The SAW device of claim 1, wherein, The surface acoustic wave device has at least one of the following characteristics: In the same edge region, the acoustic impedance of the region provided with the widened portion is less than the acoustic impedance of the region not provided with the auxiliary structure and the widened portion; In the same edge region, the acoustic impedance of the region provided with the auxiliary structure is less than the acoustic impedance of the region not provided with the auxiliary structure and the widened portion; The acoustic impedance of the region provided with the auxiliary structure is less than the acoustic impedance of the region provided with the widened portion.

4. The SAW device of claim 1, wherein, The acoustic impedance of one of the widened portion and the auxiliary structure closer to the middle region is greater than the acoustic impedance of the other farther away from the middle region.

5. The SAW device of claim 1, wherein, The length of the auxiliary structure in the arrangement direction of the two bus bars is L1, 0.01λ 6. The SAW device of claim 1, wherein, The thickness of the auxiliary structure is H1, 0.002λ 7. The SAW device of claim 1, wherein, The length of the widened portion in the arrangement direction of the two bus bars is L2, 0 8. The SAW device of claim 1, wherein, The thickness of the widened portion is equal to the thickness of the electrode finger located in the middle region.

9. The SAW device of claim 1, wherein, The width of the auxiliary structure in the arrangement direction of each electrode finger is W1, the width of the electrode finger in the arrangement direction of each electrode finger is W3, W1≥W3 / 2.

10. The SAW device of claim 1, wherein, In the same edge region, the width of the widened portion in the arrangement direction of each electrode finger is W2, the width of the electrode finger in the arrangement direction of each electrode finger is W3, the center distance between two adjacent electrode fingers is P3, W3≤W2<(2P3-W3).

11. The SAW device of claim 1, wherein, The auxiliary structure is provided on the side of the interdigital transducer facing the piezoelectric substrate; or, the auxiliary structure is provided on the side of the interdigital transducer away from the piezoelectric substrate.

12. The SAW device of claim 1, wherein, In the same edge region, the projection of the widened portion and the auxiliary structure corresponding to the same electrode finger in the top view direction is adjacent in the length extension direction of the electrode finger; or, In the same edge region, the projection of the widened portion and the auxiliary structure corresponding to the same electrode finger in the top view direction is arranged apart along the length extension direction of the electrode finger; Or, In the same edge region, the projection of the widened portion and the auxiliary structure corresponding to the same electrode finger in the top view direction is partially overlapped along the length extension direction of the electrode finger.

13. The SAW device of claim 12, wherein, In the same edge region, the projection of the widened portion and the auxiliary structure corresponding to the same electrode finger in the top view direction is arranged apart by a preset distance L3 along the length extension direction of the electrode finger, L3 < 2.6λ, λ being the period of the electrode finger; or, In the same edge region, the projection of the widened portion and the auxiliary structure corresponding to the same electrode finger in the top view direction is overlapped by a preset distance L4 along the length extension direction of the electrode finger, L4 < 2.6λ, λ being the period of the electrode finger.

14. The SAW device of claim 1, wherein, In the same edge region, the widened portion is farther away from the intermediate region than at least part of the auxiliary structure; or, In the same edge region, the widened portion is closer to the intermediate region than at least part of the auxiliary structure.

15. The SAW device of claim 1, wherein, The auxiliary structure is arranged on the side of the electrode finger facing the piezoelectric substrate; or, The auxiliary structure is arranged on the side of the electrode finger and / or the widened portion facing away from the piezoelectric substrate.

16. The SAW device of claim 1, wherein, In the top view direction, the auxiliary structure is arranged apart from or in contact with the electrode finger.

17. The SAW device of claim 1, wherein, The auxiliary structure comprises a plurality of auxiliary blocks, and in the arrangement direction of the electrode fingers, the auxiliary blocks are arranged apart in sequence; and the projection of each electrode finger and each auxiliary block in the top view direction is at least partially overlapped.

18. The SAW device of claim 1, wherein, The projection of the auxiliary structure and each electrode finger in the top view direction is overlapped in the arrangement direction of the electrode fingers, and the projection of the auxiliary structure and the gap between any two adjacent electrode fingers in the top view direction is overlapped.

19. The SAW device of claim 1, wherein, The surface acoustic wave device further comprises: A dielectric layer covering the interdigital transducer, the dielectric layer being arranged on the side of the electrode finger facing away from the piezoelectric substrate, and the dielectric layer being a temperature compensation layer.

20. The SAW device of claim 19, wherein, The auxiliary structure is arranged on the side of the dielectric layer facing away from the electrode finger; or, The dielectric layer is arranged on the side of the auxiliary structure facing away from the electrode finger.

21. The SAW device of claim 1, wherein, The piezoelectric substrate comprises a piezoelectric film and a substrate arranged in layers, and the interdigital transducer is arranged on the surface of the piezoelectric film facing away from the substrate.

22. The SAW device of claim 1, wherein, The interdigital transducer further comprises: A dummy finger, one end of which is connected to one of the bus bars, and the other end of which is arranged apart from the tip of the electrode finger connected to the other bus bar.

23. A surface acoustic wave device, the surface acoustic wave device comprising: A piezoelectric substrate; An interdigital transducer arranged on the piezoelectric substrate; In the arrangement direction of the two bus bars of the interdigital transducer, the two bus bars have a crossing region therebetween, the crossing region comprising an intermediate region and edge regions located at both ends of the intermediate region; wherein in the arrangement direction of each electrode finger of the interdigital transducer, the crossing region is the region where each electrode finger overlaps with each other; and the electrode finger comprises a widened portion located in the edge region. The auxiliary structure is provided with the widened portion and the auxiliary structure in at least one of the two edge regions; The projection of the widened portion and the auxiliary structure in the top view direction is at least partially staggered along the length extension direction of the electrode finger in the same edge region; The auxiliary structure is a conductive structure, and the auxiliary structure includes a plurality of auxiliary blocks, and each auxiliary block is sequentially and spacedly arranged in the arrangement direction of each electrode finger; each electrode finger is arranged in contact with one auxiliary block in the top view direction; A dielectric layer is arranged on the piezoelectric substrate and covers the interdigital transducer and the auxiliary structure.

24. A surface acoustic wave device, comprising: a piezoelectric substrate; an interdigital transducer arranged on the piezoelectric substrate; In the arrangement direction of the two bus bars of the interdigital transducer, the two bus bars have a crossing region therebetween, the crossing region includes a middle region and edge regions located at both ends of the middle region; in the arrangement direction of each electrode finger of the interdigital transducer, the crossing region is an area in which each electrode finger overlaps each other; the electrode finger includes a widened portion located in the edge region; An auxiliary structure is provided with the widened portion and the auxiliary structure in at least one of the two edge regions; The projection of the widened portion and the auxiliary structure in the top view direction is at least partially staggered along the length extension direction of the electrode finger in the same edge region; the auxiliary structure is a non-conductive structure; in the top view direction, a dielectric layer is arranged between the auxiliary structure and the interdigital transducer.

25. A surface acoustic wave device, comprising: a piezoelectric substrate; an interdigital transducer arranged on the piezoelectric substrate; In the arrangement direction of the two bus bars of the interdigital transducer, the two bus bars have a crossing region therebetween, the crossing region includes a middle region and edge regions located at both ends of the middle region; in the arrangement direction of each electrode finger of the interdigital transducer, the crossing region is an area in which each electrode finger overlaps each other; the electrode finger includes a widened portion located in the edge region; An auxiliary structure is located in the edge region, and the auxiliary structure includes a first region, a second region and a third region, and the first region and the third region are respectively located on two sides away from each other of the second region in the length extension direction of the electrode finger; In the same edge region, the second region overlaps the widened portion in the top view direction along the length extension direction of the electrode finger.

26. A surface acoustic wave device, comprising: a piezoelectric substrate; an interdigital transducer arranged on the piezoelectric substrate; In the arrangement direction of the two bus bars of the interdigital transducer, the two bus bars have a crossing region therebetween, the crossing region includes a middle region and edge regions located at both ends of the middle region; in the arrangement direction of each electrode finger of the interdigital transducer, the crossing region is an area in which each electrode finger overlaps each other; the electrode finger includes a widened portion located in the edge region; An auxiliary structure is located in the edge region; The widened portion comprises a fourth region, a fifth region and a sixth region, the fourth region and the sixth region are respectively located on two sides of the fifth region in the length extension direction of the electrode finger; In the same edge region, the projection of the auxiliary structure in the top view direction overlaps with the fifth region in the length extension direction of the electrode finger.

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

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

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