Elastic wave device and radio frequency front end module

Abstract

The application discloses an elastic wave device and a radio frequency front end module. The elastic wave device is provided with a base end widening portion on an electrode finger, and the base end widening portion and the projection of the free end of the adjacent electrode finger in the extending direction of the electrode finger at least partially overlap, or the bus bar is subjected to an opening treatment, the opening is rectangular, and the unopened part at least partially overlaps with the projection of the free end of the electrode finger in the extending direction of the electrode finger, so that the suppression effect of the transverse mode can be improved, the spurious mode on the left side of the resonance point of the elastic wave device can be suppressed while improving the suppression effect of the gap mode, and the Q value of the elastic wave device is improved, and the working performance of the elastic wave device is improved.

Description

Technical Field

[0001] This application relates to the field of radio frequency technology, and in particular to an elastic wave device and a radio frequency front-end module. Background Technology

[0002] Elastic wave devices, such as surface acoustic wave (SAW) filters, are widely used in electronic circuits and wireless communication systems to filter unwanted signals due to their high operating frequency, wide bandwidth, low cost, and small size. The SAW resonator is the smallest unit of a SAW filter, primarily utilizing the piezoelectric properties of piezoelectric materials to convert electrical signals into acoustic signals.

[0003] The development of radio frequency technology has placed higher demands on the performance and specifications of elastic wave devices. During operation, acoustic modes can leak into the gap region to some extent, causing secondary excitation and thus degrading the performance of the elastic wave device. Therefore, improving the performance of elastic wave devices has become an urgent problem to be solved. Summary of the Invention

[0004] This application provides an elastic wave device and a radio frequency front-end module, which can improve the suppression effect of transverse modes and, while improving the suppression effect of gap modes, can suppress the clutter modes to the left of the resonant point, thereby improving the Q value of the elastic wave device and enhancing its working performance.

[0005] In a first aspect, embodiments of this application provide an elastic wave device, comprising: a piezoelectric substrate and interdigitated electrodes disposed on one side of the piezoelectric substrate, wherein the interdigitated electrodes include two busbars spaced apart in a first direction, and a plurality of electrode fingers arranged at intervals between adjacent busbars;

[0006] The electrode finger includes a base end and a free end. The base end of any electrode finger is connected to one of the bus bars, and the free end extends to another bus bar and is spaced apart from the other bus bar. The electrode fingers connected to different bus bars are spaced apart and alternately arranged in a second direction, which intersects the first direction.

[0007] The plurality of electrode fingers includes a first electrode finger and a second electrode finger adjacent to the first electrode finger, wherein the base end of the first electrode finger and the base end of the second electrode finger are connected to different busbars;

[0008] The first electrode finger has a base end widening portion, which includes the base end and an extension portion. The extension portion extends from at least one of the two sides of the base end in the second direction. The side of the base end widening portion away from the free end is connected to the busbar. The base end widening portion is electrically connected to the busbar. The base end widening portion has a first projection in the extension direction of the electrode finger. The free end of the second electrode finger has a second projection in the extension direction of the electrode finger. The first projection and the second projection at least partially overlap.

[0009] Secondly, embodiments of this application provide an elastic wave device, comprising:

[0010] The piezoelectric substrate and the interdigitated electrode disposed on one side of the piezoelectric substrate, the interdigitated electrode including two busbars spaced apart in a first direction, and a plurality of electrode fingers located between adjacent busbars and spaced apart;

[0011] The electrode finger includes a base end and a free end. The base end of any electrode finger is connected to one of the bus bars, and the free end extends to another bus bar and is spaced apart from the other bus bar. The electrode fingers connected to different bus bars are spaced apart and alternately arranged in a second direction, which intersects the first direction.

[0012] The busbar has at least one opening on one side facing the free end of the electrode finger. The opening is rectangular in shape and has a third projection in the extension direction of the electrode finger. The free end of the electrode finger connected to another busbar has a fourth projection in the extension direction of the electrode finger. The third projection and the fourth projection do not overlap or partially overlap.

[0013] Thirdly, embodiments of this application provide an elastic wave device, including: a piezoelectric substrate and interdigitated electrodes disposed on one side of the piezoelectric substrate, wherein the interdigitated electrodes include two busbars spaced apart in a first direction, and a plurality of electrode fingers arranged at intervals between adjacent busbars;

[0014] The electrode finger includes a base end and a free end. The base end of any electrode finger is connected to one of the bus bars, and the free end extends to another bus bar and is spaced apart from the other bus bar. The electrode fingers connected to different bus bars are spaced apart and alternately arranged in a second direction, which intersects the first direction.

[0015] The busbar has at least one opening on one side facing the free end of the electrode finger. The opening has a third projection in the extension direction of the electrode finger. The free end of the electrode finger connected to another busbar has a fourth projection in the extension direction of the electrode finger. The third projection is located within the fourth projection. The opening is rectangular in shape and is axially symmetrical about the centerline of the electrode finger connected to the other busbar.

[0016] Fourthly, embodiments of this application provide a radio frequency front-end module, including the elastic wave device provided in any one of the first, second, and third aspects of this application.

[0017] The elastic wave device and RF front-end module provided in this application embodiment improve the suppression effect of transverse modes by providing a base end widening portion on the electrode fingers, and the base end widening portion at least partially overlaps with the projection of the free end of the adjacent electrode finger in the extension direction of the electrode finger; or by opening the bus bar with a rectangular opening, such that the unopened portion at least partially overlaps with the projection of the free end of the electrode finger in the extension direction of the electrode finger. In this way, the suppression effect of gap mode is improved, and the clutter mode on the left side of the resonant point of the elastic wave device is also suppressed, thereby improving the Q value of the elastic wave device and improving the working performance of the elastic wave device. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the elastic wave device provided in the embodiments of this application;

[0020] Figure 2 This is a cross-sectional structural schematic diagram of the elastic wave device provided in the embodiments of this application;

[0021] Figure 3 This is a schematic diagram of the structure of an elastic wave device provided in an embodiment of this application;

[0022] Figure 4 This is another structural schematic diagram of an elastic wave device provided in an embodiment of this application;

[0023] Figure 5 This is another structural schematic diagram of an elastic wave device provided in the embodiments of this application;

[0024] Figure 6This is another structural schematic diagram of an elastic wave device provided in the embodiments of this application;

[0025] Figure 7 This is another structural schematic diagram of an elastic wave device provided in the embodiments of this application;

[0026] Figure 8 This is another structural schematic diagram of an elastic wave device provided in the embodiments of this application;

[0027] Figure 9 This is another structural schematic diagram of an elastic wave device provided in the embodiments of this application;

[0028] Figure 10 This is a schematic diagram of another elastic wave device provided in the embodiments of this application;

[0029] Figure 11 This is a schematic diagram of another elastic wave device provided in the embodiments of this application;

[0030] Figure 12 This is a comparison chart of admittance curves of the embodiments of this application and related technology 1;

[0031] Figure 13 This is a comparison chart of the Q values ​​of the embodiments of this application and related technology 1;

[0032] Figure 14 This is a comparison chart of admittance curves of the embodiments of this application and related technology 2;

[0033] Figure 15 This is a comparison chart of the Q values ​​of the embodiments of this application and related technology 2;

[0034] Figure 16 This is a comparison chart of admittance curves of the embodiments of this application and related technology 3;

[0035] Figure 17 This is a comparison chart of the Q values ​​of the embodiments of this application and related technology 3;

[0036] Figure 18 This is a schematic diagram of the structure of an elastic wave device in related technologies.

[0037] Explanation of icon numbers:

[0038] 10. Piezoelectric substrate; 11. Piezoelectric layer; 12. Substrate;

[0039] 20. Interdigitated electrodes; 30. Reflective structure; 40. Temperature compensation layer;

[0040] 21. Busbar; 21a. First busbar; 21b. Second busbar; 211. Opening;

[0041] 22. Electrode finger; 22a. Third electrode finger; 22b. Fourth electrode finger; 221. Base end; 222. Free end; 223. Widened portion of base end;

[0042] 23. Imaginary finger; 24. Load structure; 25. Conductive strip. Detailed Implementation

[0043] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0044] The following descriptions of the embodiments are based on the accompanying illustrations and are used to illustrate specific embodiments in which this application can be implemented. The component designations used herein, such as "first," "second," etc., are merely for distinguishing the described objects and have no sequential or technical meaning. Unless otherwise specified, the terms "connection" and "linkage" used in this application include both direct and indirect connections (linkages). Directional terms used in this application, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "side," etc., are merely for reference to the accompanying illustrations. Therefore, the use of directional terms is for better and clearer explanation and understanding of this application, and does not indicate or imply that the referred device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this application.

[0045] Furthermore, the terms “comprising,” “may include,” “include,” or “may contain” used in this application indicate the presence of the corresponding functions, operations, elements, etc. disclosed, but do not limit other one or more additional functions, operations, elements, etc.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0047] It should be noted that the elastic wave device mentioned in the embodiments of this application includes, but is not limited to, surface acoustic wave (SAW) resonators, longitudinally coupled SAW filters, and SAW filters composed of multiple SAW resonators and / or longitudinally coupled SAW filters connected in series and parallel, etc., devices with interdigitated electrodes on a piezoelectric substrate. The SAW resonator can be a normal-SAW resonator, a temperature-compensated SAW resonator, a thin-film SAW resonator with a multilayer substrate structure, or a laterally excited thin-film bulk acoustic wave resonator, etc., and is not specifically limited in the embodiments of this application. The elastic wave device in the embodiments of this application is described using a surface acoustic wave resonator as an example.

[0048] In related technologies, to suppress the transverse modes of surface acoustic wave (SAW) resonators, the electrode fingers are typically widened and thickened in the corresponding region at the free end. This can suppress transverse modes to some extent. However, in TC-SAW, especially in multilayer substrate SAW filters, the generation of higher-order transverse modes cannot be achieved or completely suppressed using traditional techniques. To suppress higher-order miscellaneous modes, short-circuit metal strips are added to the gap region of the SAW resonator, but the suppression effect needs further improvement. Simultaneously, to suppress gap modes, the electrode fingers of the SAW resonator are configured with a bent-finger structure, which can also suppress higher-order miscellaneous modes to some extent. However, all three structures mentioned above generate miscellaneous modes to the left of the resonant point of the SAW resonator. In particular, while these three structures can suppress transverse modes, their suppression effect on gap modes and miscellaneous modes to the left of the resonant point is limited, failing to achieve optimal performance requirements.

[0049] To address the aforementioned issues, this application provides an elastic wave device. By widening the base end of the electrode finger and controlling its relative positional relationship during widening, the device overlaps with the projection of the free end of the electrode finger in the extension direction of the electrode finger. Alternatively, by making a rectangular opening in the busbar, the unopened portion of the busbar overlaps with the projection of the free end of the electrode finger in the extension direction of the electrode finger. This improves the suppression effect of transverse modes and, while improving the suppression effect of gap modes, also suppresses stray modes to the left of the resonant point, thereby enhancing the performance of the elastic wave device.

[0050] This application provides an elastic wave device; please refer to [link to relevant documentation]. Figures 1-3 .like Figure 1 As shown, the elastic wave device includes a piezoelectric substrate 10, an interdigitated electrode 20 disposed on one side of the piezoelectric substrate 10, and two reflective structures 30, with the interdigitated electrode 20 located between the two reflective structures 30.

[0051] Specifically, such as Figure 3As shown, the interdigitated electrode 20 includes at least two spaced busbars 21 (e.g., a first busbar 21a and a second busbar 21b) and a plurality of electrode fingers 22. In the following embodiments, two spaced busbars are used as an example. Other numbers of busbars are within the scope of this application. The first busbar 21a and the second busbar 21b extend along a second direction (X direction in the figure) and are arranged opposite to each other and spaced apart along a first direction (Y direction in the figure). The electrode fingers 22 are located between the first busbar 21a and the second busbar 21b and are spaced apart along the X direction.

[0052] Each electrode finger 22 includes a base end 221 and a free end 222. The electrode finger 22 includes multiple third electrode fingers 22a and multiple fourth electrode fingers 22b. The base end 221 of the third electrode finger 22a is connected to a first busbar 21a, and the free end 222 of the third electrode finger 22a extends towards a second busbar 21b, spaced apart from it. The base end 221 of the fourth electrode finger 22b is connected to the second busbar 21b, and the free end 222 of the fourth electrode finger 22b extends towards the first busbar 21a, spaced apart from it. The third electrode fingers 22a and the fourth electrode fingers 22b are in a second direction (…). Figure 3 Alternately set in the X direction (of the model).

[0053] It is understood that in this embodiment, the first direction refers to the arrangement direction of the first busbar 21a and the second busbar 21b, and the second direction refers to the arrangement direction of the electrode fingers 22. This direction and the extension direction of the electrode fingers can be located in the same plane and intersect. In one embodiment, the first busbar 21a and the second busbar 21b are orthogonal to the extension direction of the electrode fingers 22. Then the first direction is equivalent to the extension direction of the electrode fingers 22. Therefore, the first direction and the second direction intersect and are orthogonal, and the angle formed by the first direction and the second direction is 90°. In another embodiment, the first busbar 21a and the second busbar 21b intersect the extension direction of the electrode fingers 22. That is, the busbar 21 is inclined relative to the electrode fingers 22. Then the first direction and the extension direction of the electrode fingers 22 intersect. Therefore, the first direction and the second direction intersect but are not orthogonal, that is, the angle formed by the first direction and the second direction is an acute angle or an obtuse angle. This embodiment takes the first direction and the second direction being orthogonal, that is, the first direction being the extension direction of the electrode fingers, as an example for further explanation.

[0054] In this embodiment of the application, the electrode finger 22 includes a first electrode finger. The first electrode finger may refer to one or more electrode fingers in the electrode finger 22 (i.e., a portion of the electrode fingers in the electrode finger 22), or it may refer to any one of the electrode fingers in the electrode finger 22. This embodiment of the application does not make any specific limitation.

[0055] It should be noted that the embodiments and accompanying drawings of this application are described using any one of the electrode fingers 22 as an example.

[0056] In this embodiment, the electrode finger adjacent to the first electrode finger is defined as the second electrode finger, and the base end of the second electrode finger is connected to a different busbar 21 as the base end of the first electrode finger. If there is one electrode finger adjacent to the first electrode finger, the second electrode finger is that electrode finger. If there are two electrode fingers adjacent to the first electrode finger, the second electrode finger can be one or either of the two electrode fingers; this embodiment does not impose a specific limitation.

[0057] In this embodiment, the first electrode finger is provided with a base end widening portion 223. The base end widening portion 223 includes the base end 221 and an extension portion. The extension portion extends from at least one of the two sides of the base end 221 in a second direction (X direction in the figure) in a direction away from the base end, so that the side of the base end widening portion 223 away from the free end 222 is connected to the busbar. The first electrode finger is electrically connected to the busbar through one end of the base end widening portion 223, and the other end of the base end widening portion 223 is spaced apart from the free end of the second electrode finger. The base end widening portion 223 is in the extension direction of the electrode finger ( Figure 3 The first projection is in the Y direction of the second electrode, and the free end 222 of the second electrode finger has a second projection in the Y direction. The first projection and the second projection at least partially overlap.

[0058] It should be noted that the base end widening portion 223 can be understood as the base end 221 of the electrode finger 22 and the region that widens the base end 221 in the X direction. For example, when the first electrode finger is connected to the first busbar 21a, the base end widening portion 223 of the first electrode finger is connected to the first busbar 21a on the side away from the free end of the first electrode finger.

[0059] It is understandable that the second projection can be completely located within the first projection, that is, the first projection can completely cover the second projection; the second projection can also partially overlap with the first projection, that is, the first projection covers part of the second projection.

[0060] It is understandable that, among the first electrode fingers connected to the same busbar, the base widening portions 223 of two adjacent first electrode fingers have a gap in the X direction.

[0061] In this embodiment, by adding a base widening portion to some electrode fingers, so that the projection of the electrode finger in the extension direction overlaps with the projection of the free end of the adjacent electrode finger in the same direction, not only can the transverse mode suppression effect be improved, but also the gap mode suppression effect can be improved while suppressing the miscellaneous modes on the left side of the resonant point of the elastic wave device, thereby improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device.

[0062] Preferably, all electrode fingers are provided with a base widening portion, so that the projection of the electrode finger in the extension direction overlaps with the projection of the free end of the adjacent electrode finger in the same direction. This can further improve the transverse mode suppression effect, and while further improving the gap mode suppression effect, it can further suppress the miscellaneous modes on the left side of the resonant point of the elastic wave device, thereby improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device.

[0063] Figure 2 for Figure 1 A schematic diagram of a cross-sectional structure taken along the X direction. In one embodiment, the piezoelectric substrate 10 of the elastic wave device may include a piezoelectric layer 11. Figure 2 (a) An example is shown where the interdigitated electrode 20 is disposed on one side of the piezoelectric layer 11. The piezoelectric layer 11 can be a single layer or multiple layers of piezoelectric materials with piezoelectric properties, such as aluminum nitride, zinc oxide, lead zirconate titanate (PZT), or rare earth element doping materials disposed in the above materials at a certain atomic ratio; or a single crystal piezoelectric material can be selected, such as single crystal aluminum nitride, lithium niobate, lithium tantalate, quartz, etc., which is not limited in this embodiment.

[0064] In another embodiment, the piezoelectric substrate 10 of the elastic wave device may include a piezoelectric layer 11 and a substrate 12 stacked in the thickness direction (i.e., the Z direction) of the interdigital electrode 20 or electrode finger 22. Figure 2 (b) An example is shown where the interdigitated electrode 20 is disposed on the side of the piezoelectric layer 11 away from the substrate 12. One or more functional layers may also be disposed between the piezoelectric layer 11 and the substrate 12, such as high and low acoustic impedance layers or other films. In one embodiment, high acoustic impedance layers may be alternately disposed with low acoustic impedance layers in sequence, and the substrate 12 may be made of materials such as silicon, quartz, sapphire, and silicon carbide.

[0065] In the embodiments of this application, the material of the interdigitated electrode 20 can be a single metal material or a composite or alloy of different metals. Optionally, the aforementioned material can be one of aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, or a composite or alloy of the above metals. Specifically, the materials of the busbar 21 and the electrode fingers 22 can be the same or different. The busbar 21 and the electrode fingers 22 can be a single-layer metal film or a stacked metal film with multiple metal layers. This application embodiment does not impose limitations.

[0066] In one embodiment, as Figure 2 shown, the elastic wave device may further include a temperature compensation layer 40 for adjusting the frequency temperature coefficient of the elastic wave device. In Figure 2 the structure shown, in the Z direction, the temperature compensation layer 40 is disposed on one side of the piezoelectric substrate 10 provided with the interdigital electrodes 20 and covers the interdigital electrodes 20. The material of the temperature compensation layer 40 may be at least one of dielectric materials having a positive temperature compensation coefficient such as silicon oxide, silicon nitride, silicon oxynitride, tellurium dioxide, and silicon oxyfluoride.

[0067] In another embodiment, a passivation layer and / or a frequency modulation layer (not shown in the figure) may also be covered on the side of the temperature compensation layer 40 facing away from the piezoelectric substrate 10 to protect the interdigital electrodes 20 and / or frequency modulate the elastic wave device. The material of the passivation layer and / or the frequency modulation layer may be at least one of silicon dioxide, silicon nitride, silicon oxynitride, aluminum nitride, and aluminum oxide.

[0068] In yet another embodiment, the passivation layer may also separately cover the interdigital electrodes 20 to protect the interdigital electrodes 20.

[0069] In the embodiments of the present application, for an elastic wave device provided with a temperature compensation layer and an elastic wave device having a multi-layer substrate structure, its operating frequency is relatively high, and the influence of spurious modes on its operating performance is more obvious. Therefore, by providing a base end widened portion for the electrode fingers, and making the projection of the base end widened portion in the extending direction of the electrode fingers at least partially overlap with the projection of the free ends of adjacent electrode fingers in the same direction, not only can the lateral mode suppression effect be further improved, but also the gap mode suppression effect can be further improved while further suppressing the spurious modes on the left side of the resonance point of the elastic wave device, thereby greatly improving the Q value of the elastic wave device and enhancing the operating performance of the elastic wave device.

[0070] In a feasible embodiment, it is defined that the size of the base end widened portion 223 of the first electrode finger in the second direction (such as Figure 3 the X direction in

[0071] The width of the base-end widened portion 223 is limited within this range, which can make the first projection of it in the electrode finger extension direction overlap at least partially with the second projection of the free end 222 of the adjacent electrode finger in the same direction, and be spaced apart from the base-end widened portions 223 of other first electrode fingers, thus being beneficial to improving the lateral mode suppression effect, and while improving the gap mode suppression effect, being beneficial to suppressing the spurious modes on the left side of the resonance point of the elastic wave device, and further improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device.

[0072] Specifically, W1 can be 0.6λ, 0.7λ, 0.8λ, 0.9λ, etc., and the embodiments of the present application do not make limitations.

[0073] In one implementation manner, define the size of the base-end widened portion 223 of the first electrode finger in the extension direction of the electrode finger 22 (such as Figure 3 the Y direction in the figure) as L1, that is, the length of the base-end widened portion 223, 0.2λ < L1 < 5λ.

[0074] The length of the base-end widened portion 223 is limited within this range, and the first projection of the base-end widened portion in the Y direction overlaps at least partially with the second projection of the free end of the adjacent electrode finger in the same direction, thus being beneficial to improving the lateral mode suppression effect, and while further improving the gap mode suppression effect, being beneficial to further suppressing the spurious modes on the left side of the resonance point of the elastic wave device, and further improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device. If L1 is too large or too small, it will cause the amplitude of the lateral mode or the gap mode to become stronger.

[0075] Specifically, L1 can be 0.3λ, 0.5λ, 0.8λ, λ, 2λ, 3λ, 4λ, 4.9λ, etc., and the embodiments of the present application do not make limitations.

[0076] In a preferred implementation manner, 0.2λ < L1 < 3λ. Specifically, L1 can be 0.3λ, 0.6λ, 0.9λ, 1.2λ, 1.5λ, 2λ, 2.5λ, 2.9λ, etc., which is not only beneficial to the suppression of the lateral mode, the gap mode and the spurious modes on the left side of the resonance point, but also can achieve the miniaturization of the device.

[0077] In another implementation manner, define the distance between the base-end widened portion 223 of the first electrode finger and the free end 222 of the second electrode finger in the extension direction of the electrode finger 22 (such as Figure 3 the Y direction in the figure) as L2, 0.1λ < L2 < 5λ.

[0078] The distance between the base widening portion 223 and the free end 222 of the second electrode finger is limited within this range, and the first projection of the base widening portion in the Y direction and the second projection of the free end of the adjacent electrode finger in the same direction at least partially overlap, which is beneficial to improving the lateral mode suppression effect. While further improving the gap mode suppression effect, it is beneficial to further suppress the spurious modes on the left side of the resonance point of the elastic wave device, thereby improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device. If L2 is too large, the size of the elastic wave device will increase; if it is too small, the process difficulty will increase.

[0079] Specifically, L2 can be 0.2λ, 0.5λ, 0.8λ, λ, 2λ, 3λ, 4λ, 4.9λ, etc., which are not limited in the embodiments of the present application.

[0080] In a preferred embodiment, 0.1λ < L2 < 3λ. Specifically, L2 can be 0.3λ, 0.6λ, 0.9λ, 1.2λ, 1.5λ, 2λ, 2.5λ, 2.9λ, etc.

[0081] In another embodiment, it is defined that the size of the base widening portion 223 of the first electrode finger in the thickness direction of the piezoelectric substrate 10 (i.e., Figure 2 the Z direction in the figure) is H1, that is, the thickness of the base widening portion 223, and the thickness of the electrode finger is H2, where H2 ≤ H1 ≤ 1.8H2.

[0082] It can be understood that the thickness H1 can be the same as the thickness H2, or the thickness H1 can also be 1.2H2, 1.5H2, 1.8H2. By setting the thickness H2 of the base widening portion 223 within this range, it is beneficial to further improve the suppression effect of the gap mode.

[0083] Preferably, H1 = H2, which is convenient for process processing.

[0084] In an exemplary embodiment, as Figure 3 shown, the second electrode finger is one of the two electrode fingers adjacent to the first electrode finger. In the second direction (the X direction in the figure), one side of the base widening portion 223 is flush with one side of the first electrode finger on the same side, and the other side of the base widening portion 223 protrudes from the other side of the first electrode finger. That is to say, for the base 221 of the first electrode finger, the base widening portion 223 is only widened on one side, and the other side is flush with the side edge of the base of the first electrode finger. For details, see Figure 3In the middle, the right side of the base end widening portion 223 is on the same straight line and flush with the right side of the first electrode finger, so that the projection of the widened side in the Y direction at least partially overlaps with the second projection of the free end of the second electrode finger in the Y direction, which is beneficial to improving the transverse mode suppression effect. While improving the gap mode suppression effect, it is also beneficial to suppress the miscellaneous modes on the left side of the resonant point of the elastic wave device, thereby improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device.

[0085] In another exemplary embodiment, the second electrode finger is one of two electrode fingers adjacent to the first electrode finger. In the second direction, both sides of the base widening portion 223 protrude from the two sides of the first electrode finger respectively. However, the projection of the base widening portion 223 closer to the second electrode finger in the electrode finger extension direction at least partially overlaps with the second projection of the free end of the second electrode finger in the same direction, while the projection of the base widening portion 223 away from the second electrode finger in the electrode finger extension direction does not overlap with the projection of the free end of another adjacent electrode finger in the same direction. That is, when the base widening portion 223 is widened to both sides of the first electrode finger, only one side at least partially overlaps with the projection of the free end of the adjacent electrode finger in the electrode finger extension direction, while the projection of the other side does not overlap.

[0086] In yet another exemplary implementation, such as Figure 4 As shown, the second electrode finger is either one of the two electrode fingers adjacent to the first electrode finger, or it can be understood as the two electrode fingers adjacent to the first electrode finger. In the second direction (X direction in the figure), both sides of the base end widening portion 223 protrude from the two sides of the first electrode finger, so that the first projection of the base end widening portion 223 in the electrode finger extension direction (Y direction in the figure) partially overlaps with the second projection of the free ends of the two second electrode fingers in the Y direction. There is a gap between the base end widening portions 223 of two adjacent first electrode fingers connected to the same busbar.

[0087] It is understandable that the distances by which the base widening portion 223 protrudes from the two sides of the first electrode finger can be the same or different. In other words, the overlapping areas between the first projection of the base widening portion 223 and the second projections of the second electrode fingers on both sides can be the same or different.

[0088] In a preferred embodiment, the overlapping areas between the first projection of the base-end widening portion 223 and the second projections of the second electrode fingers on both sides can be the same, so that the base-end widening portion 223 is arranged axially symmetrically with the midline of the first electrode finger as the axis of symmetry. Thus, by controlling the projection relationship of the first projection of the base-end widening portion 223 relative to the second projections of the two second electrode fingers on both sides thereof, the position and size of the base-end widening portion 223 can be controlled. In one embodiment, the gap formed between two adjacent base-end widening portions 223 can be arranged symmetrically with respect to the central axis of the electrode finger above the gap, so that the gap between two adjacent base-end widening portions 223 and the base-end widening portion 223 within the gap area can better act on the sound velocity, thereby improving the gap mode suppression effect and the suppression effect of the spurious mode on the left side of the resonance point of the elastic wave device.

[0089] The embodiment of the present application can improve the lateral mode suppression effect, the gap mode suppression effect and the suppression effect of the spurious mode on the left side of the resonance point of the elastic wave device, and further improve the Q value of the elastic wave device, while being beneficial to the process manufacturing.

[0090] In one embodiment, in Figure 4 In the structure shown, the range of the width W1 of the base-end widening portion 223 can be: (1 - 0.5*DF)λ < W1 < λ. Where DF is the duty ratio of the electrode finger, that is, the ratio of the size of the electrode finger in the second direction to P.

[0091] The embodiment of the present application can make the first projection partially overlap with the second projections of the second electrode fingers on both sides respectively when the base-end widening portion 223 protrudes towards both sides of the first electrode finger. This is beneficial to improving the lateral mode suppression effect, and while improving the gap mode suppression effect, it can suppress the spurious mode on the left side of the resonance point of the elastic wave device, and further improve the Q value of the elastic wave device.

[0092] It can be understood that between multiple first electrode fingers connected to the same bus bar (such as the first bus bar 21a), the length L1 of the base-end widening portion 223 can be equal or unequal, the width W1 can be equal or unequal, and the distance L2 between the base-end widening portion and the free end of the second electrode finger can be equal or unequal, which is not limited in the embodiment of the present application.

[0093] In a preferred embodiment, L1, L2, and W1 between multiple first electrode fingers connected to the same bus bar can all be equal, which is convenient for the process manufacturing.

[0094] It is understood that the length L1 of the base end widening portion 223 between any two first electrode fingers can be equal or unequal, the width W1 can be equal or unequal, and the distance L2 between the base end widening portion 223 and the free end of the second electrode finger can be equal or unequal. This application does not limit the specific embodiment.

[0095] In a preferred embodiment, L1 between any two first electrode fingers can be equal, L2 can be equal, and W1 can be equal, thereby ensuring the consistency of the structure in different regions and ensuring the suppression effect in different regions.

[0096] In one embodiment, the L1 and its corresponding L2 of a plurality of first electrode fingers connected to the same busbar can be set to be different, so that the free ends of the first electrode fingers or second electrode fingers connected to the same busbar can form an apodization pattern.

[0097] In one exemplary embodiment, when L1 is set to different lengths, L2 is set to the same length. That is, the position of the free end 222 of the second electrode finger will change with the adjustment of the length of the base end widening portion 223, so that the free ends of the multiple electrode fingers connected to another busbar also form corresponding apodization patterns. Specifically, the apodization pattern can be wavy, zigzag, arc, oblique line, irregular pattern, etc., which are not limited in the embodiments of this application.

[0098] In another exemplary embodiment, L1 is set to different lengths, and L2 is also set to different lengths. W1 can be the same or different, and this application embodiment does not limit this. For example, in one embodiment, the apodization pattern formed by the free ends of the multiple electrode fingers connecting to another busbar is the same as the apodization pattern formed by the base widening portion 223, thereby ensuring the gap mode suppression effect and the suppression effect on the left side of the resonance point. In another embodiment, L1 is set to different lengths, L2 is set to different lengths, and the distance between the free end of each electrode finger and the corresponding busbar is ensured to be the same, thereby simplifying the fabrication process while ensuring the suppression effect on the gap mode and the left side of the resonance point.

[0099] In this embodiment, by adjusting L1, an apodization pattern is formed on the side of the base widening portion that is away from the busbar, which helps to improve the suppression effect of miscellaneous modes.

[0100] In another exemplary embodiment, L1 is set to the same length, while L2 of the multiple first electrode fingers connected to the same busbar is different, to form an apodization pattern. It is understood that L2 can exhibit an apodization pattern by changing L1, or, with L1 being the same, the position of the free end of the second electrode finger can be adjusted to achieve the same apodization pattern. W1 can be the same or different; this application embodiment does not limit this. Specifically, the apodization pattern can be wavy, zigzag, arc-shaped, diagonal, irregular, etc., and this application embodiment does not limit this.

[0101] In this embodiment of the application, adjusting L2 can help improve the suppression effect of heterogeneous modes.

[0102] In this embodiment, by adjusting L1 and / or L2 of the first electrode finger, an apodization pattern is formed between the end of the base widened portion that is away from the bus bar and / or between the free ends of the electrode finger. The apodization pattern can be a periodic apodization, such as satisfying a periodic function, like a trigonometric function, or it can be a non-periodic apodization. This embodiment does not limit the specific apodization pattern.

[0103] For example, please refer to Figure 5 The base widening portion 223 has a dimension of W1 in the second direction (X direction in the figure). In the second direction, the W1 of multiple first electrodes connected to the same busbar is the same. L1 gradually increases or decreases, thereby better suppressing higher-order gap modes.

[0104] For example, all the electrode fingers of the interdigital electrode 20 are the first electrode fingers. The electrode fingers can be divided into multiple regions. N adjacent electrode fingers correspond to the same region, N≥2. In each region, L1 changes in a gradually increasing / decreasing manner.

[0105] In this embodiment, the projection of the base-end widening portion 223 onto the piezoelectric substrate can be a rectangle, trapezoid, or other shape, and this embodiment does not impose any limitation. Therefore, in this embodiment, the dimension W1 of the base-end widening portion 223 in the second direction can refer to the maximum width of the base-end widening portion 223, and this embodiment does not impose any limitation.

[0106] In a preferred embodiment, the projection of the base widening portion 223 onto the piezoelectric substrate is rectangular, which can better improve the transverse mode suppression effect, and further improve the gap mode suppression effect and the suppression effect of the miscellaneous mode on the left side of the resonance point. This improves the Q value of the elastic wave device and facilitates the manufacturing process.

[0107] In one feasible embodiment, the interdigital electrode 20 further includes a pseudo-finger 23, one end of which is connected to the base end widening portion 223, and the other end faces the free end of the second electrode finger and is spaced apart from the free end of the second electrode finger.

[0108] Please refer to Figure 6 , in Figure 6 , all electrode fingers 22 are provided with base end widening portions 223, and the lengths L1 of the base end widening portions 223 are equal, and the widths W1 are also equal.

[0109] It can be understood that the dummy finger 23 is arranged at one end of the base end widening portion 223 away from the bus bar. Preferably, the midline of the dummy finger 23 of the first electrode finger coincides with the midline of the second electrode finger. The width of the dummy finger 23 (the dimension in the second direction) can be equal to, greater than, or less than the width of the electrode finger. The lengths of the dummy fingers (the dimensions of the dummy fingers in the extending direction of the electrode fingers) can be equal or unequal, which is not limited in the embodiments of the present application.

[0110] In another embodiment, one side of the dummy finger 23 is flush with the base end widening portion 223 on the same side, so that there is sufficient spacing between the dummy finger 23 and the electrode finger on the same base end widening portion 223, thereby avoiding the influence of the dummy finger 23 on the electrode finger and reducing the sudden change of the sound velocity at the end, and further improving the suppression effect of the gap mode.

[0111] Preferably, the width of the dummy finger 23 is equal to the width of the electrode finger, and the lengths of the dummy fingers 23 can also be equal.

[0112] In the embodiments of the present application, the setting of the dummy finger 23 is beneficial to improving the Q value of the elastic wave device.

[0113] In one embodiment, for multiple first electrode fingers connected to the same bus bar, when the lengths L1 of their base end widening portions 223 are different to form a tapered pattern, dummy fingers with the same length (the dimension in the extending direction of the electrode fingers) are arranged at the base end widening portions; in another embodiment, when the lengths L1 of their base end widening portions 223 are the same, dummy fingers with different lengths are arranged to form a tapered pattern at the ends of the dummy fingers, which is beneficial to further improving the Q value of the elastic wave device.

[0114] In one embodiment, when the dummy finger 23 is provided, the range of the width W1 of the base end widening portion 223 can be: (1 + DF) * P < W1 < λ, so that by controlling the width of the base end widening portion and the relative positions of the base end widening portion with respect to the dummy finger and the electrode finger, the lateral mode suppression effect can be further improved, and while further improving the gap mode suppression effect, the suppression effect of the spurious mode on the left side of the resonance point can be further improved, and the Q value of the elastic wave device can be further improved.

[0115] It should be noted that, in the embodiments of this application, regardless of whether the aberration is achieved by changing the length of the pseudo-finger 23 and / or by widening the base end 223, the aberration patterns formed by the aberrations near the first busbar 21a and the second busbar 21b can be the same or different, and can be symmetrical or asymmetrical. This application does not impose any limitations on this.

[0116] In one embodiment, electrode fingers 22 connected to different busbars 21 are alternately arranged in a second direction to form an alternating region; in the extension direction of the electrode fingers 22, the alternating region includes a middle region and edge regions located on both sides of the middle region; the interdigitated electrode 20 also includes a load structure 24, which is located in the edge region.

[0117] Specifically, please refer to Figure 7 and Figure 8 ,like Figure 7 As shown, the first busbar 21a and the second busbar 21b are respectively disposed in two busbar regions. Multiple third electrode fingers 22a are connected to the first busbar 21a, and multiple fourth electrode fingers 22b are connected to the second busbar 21b. Both the third electrode fingers 22a and the fourth electrode fingers 22b have a base widening portion, and the width W1 and length L1 of the base widening portion are equal. The third electrode fingers 22a and the fourth electrode fingers 22b are alternately disposed to form an alternating region. The alternating region is separated from the busbar region by a gap region. The alternating region includes a middle region and two edge regions located on either side of the middle region in the extension direction of the electrode fingers 22.

[0118] For example, the load structure 24 may be a widening of the portion of the electrode finger 22 located in the edge region (e.g., Figure 7 As shown), thickened (as shown) Figure 8 As shown in (a), the layer can be widened and thickened, or a strip structure of low-velocity material can be provided on the side of the temperature compensation layer away from the piezoelectric substrate 10 (such as...). Figure 8 As shown in (b), etc., the embodiments of this application are not limited in this respect.

[0119] It is understandable that the width of the thickened portion can be smaller than the width of electrode finger 22 (e.g., Figure 8 As shown in (a), it can also be equal to the width of electrode finger 22, but this application does not limit it in the embodiments.

[0120] In this embodiment, the load structure 24 increases the mass load in the edge region, thereby reducing the sound velocity of sound waves propagating in the edge region and suppressing transverse modes. Furthermore, in the elastic wave device with a mass load, the electrode fingers of the elastic wave device are provided with a base end widening portion, such that the first projection of the base end widening portion in the extension direction of the electrode finger at least partially overlaps with the second projection of the free end of the adjacent electrode finger in the extension direction. Compared with other elastic wave devices with the same mass load, this not only suppresses gap modes and left-side miscellaneous modes at the resonant point, but also further improves the suppression effect of transverse modes, increases the Q value of the elastic wave device, and further improves the operating performance of the elastic wave device. Combined with the pseudo-finger 23, the Q value of the elastic wave device can be further improved.

[0121] It is understood that the load structure 24 of the two edge regions can be the same or different. For example, one edge region can be widened and the other edge region can be thickened. Alternatively, one edge region can be provided with a strip structure of low sound velocity material and the other edge region can be widened. This application embodiment does not limit this.

[0122] In a preferred embodiment, the load structures 24 on both side edge regions are identical, facilitating manufacturing processes. The accompanying drawings of this application illustrate the embodiments using the example of a widened counter electrode finger 22 as the load structure 24.

[0123] In one feasible implementation, please refer to Figure 9 The first electrode finger is any one of the multiple electrode fingers 22. The interdigitated electrode 20 also includes a conductive strip 25, which is connected to the base end widening portion of the multiple first electrode fingers connected to the same busbar 21. In the extension direction of the electrode finger 22 (i.e., the Y direction in the figure), the distance D1 between the conductive strip 25 and the side of the base end widening portion 223 near the free end of the second electrode finger is greater than 0, and the distance D2 between the conductive strip 25 and the busbar 21 is greater than 0.

[0124] In this embodiment, the material of the conductive strip 25 may be one of aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, or a composite of the above metals or their alloys. It may be the same as or different from the material of the interdigital electrode 20. This embodiment does not limit the material.

[0125] exist Figure 9Among them, all electrode fingers 22 are first electrode fingers, that is, a base-end widening portion 223 is provided on all electrode fingers. For example, for the third electrode finger 22a connected to the first bus bar 21a, the conductive bar 25 is connected to the base-end widening portion 223 of these third electrode fingers 22a; for the fourth electrode finger 22b connected to the second bus bar 21b, the conductive bar 25 is connected to the base-end widening portion 223 of these fourth electrode fingers 22b. For the conductive bar 25 connected to the base-end widening portion 223 of the third electrode finger 22a, there is a spacing between it and the first bus bar 21a, and there is also a spacing on the side of the base-end widening portion 223 of the third electrode finger 22a背离 the first bus bar 21a; for the conductive bar 25 connected to the base-end widening portion 223 of the fourth electrode finger 22b, there is a spacing between it and the second bus bar 21b, and there is also a spacing on the side of the base-end widening portion 223 of the fourth electrode finger 22b背离 the second bus bar 21b.

[0126] In the embodiment of the present application, on the basis of providing a base-end widening portion at the base end of the electrode finger, a conductive bar is provided, and in the extending direction of the electrode finger, there are spacings on both sides of the conductive bar and the base-end widening portion 223, so that it is possible to further suppress high-order hybrid modes on the basis of suppressing transverse modes, gap modes, and hybrid modes on the left side of the resonance point, thereby improving the working performance of the elastic wave device. And combined with the load structure 24, the transverse mode can be further suppressed.

[0127] In a specific embodiment, the size W2 of the conductive bar 25 in the extending direction of the electrode finger (i.e., Figure 9 the Y direction in satisfies 0.1λ ≤ W2 ≤ 0.4λ, and specifically, it can be 0.1λ, 0.2λ, 0.3λ, 0.4λ, etc., and the embodiment of the present application does not limit this. Limiting W2 within this range can further improve the effect of suppressing high-order hybrid modes.

[0128] In another specific embodiment, 0.1λ < D1 < 2.5λ, and specifically, it can be 0.2λ, 0.5λ, λ, 1.3λ, 1.7λ, 2λ, 2.4λ, etc. Limiting D1 within this range can not only effectively suppress high-order hybrid modes but also be beneficial to suppressing gap modes.

[0129] In yet another specific embodiment, 0.1λ < D2 < 2.5λ, and specifically, it can be 0.2λ, 0.5λ, λ, 1.3λ, 1.7λ, 2λ, 2.4λ, etc. Limiting D2 within this range can not only effectively suppress high-order hybrid modes but also be beneficial to suppressing gap modes.

[0130] It can be understood that for multiple first electrode fingers connected to the same bus bar 21, the conductive bar 25 connected to their base-end widening portions 223 can be one or multiple; the conductive bar 25 can be arranged parallel to the bus bar 21 or can be arranged obliquely relative to the bus bar 21, and the embodiment of the present application does not limit this.

[0131] Please see Figure 10 and Figure 11 This application also provides an elastic wave device, which differs from the elastic wave device provided in the previous embodiment in that the elastic wave device provided in the previous embodiment is implemented by setting a base end widening portion on the electrode finger, while the elastic wave device provided in this embodiment is implemented by a bus bar opening.

[0132] In one implementation, specifically, such as Figure 10 As shown, the elastic wave device provided in this application embodiment also includes: a piezoelectric substrate and interdigitated electrodes disposed on one side of the piezoelectric substrate. The interdigitated electrodes include two busbars 21 (e.g., a first busbar 21a and a second busbar 21b) spaced apart in a first direction, and a plurality of electrode fingers 22 located between the first busbar 21a and the second busbar 21b and spaced apart.

[0133] Electrode finger 22 includes a base end 221 and a free end 222. The base end 221 of any electrode finger 22 is connected to a bus bar, and the free end 222 extends to another bus bar and is spaced apart from the other bus bar. Electrode fingers connected to the first bus bar 21a and the second bus bar 21b are spaced apart and alternately arranged in a second direction, and the second direction intersects the first direction. Figure 10 In the structure shown, the second direction is orthogonal to the first direction.

[0134] The busbar 21 has at least one opening 211 on the side facing the free end of the electrode finger 22. The opening 211 is rectangular in shape and has a third projection in the extension direction of the electrode finger 22. The free end 222 of the electrode finger connected to another busbar has a fourth projection in the extension direction of the electrode finger 22. The third projection and the fourth projection do not overlap or partially overlap.

[0135] In this embodiment, one of the first busbar 21a and the second busbar 21b is provided with a rectangular opening 211. Alternatively, both the first busbar 21a and the second busbar 21b may be provided with rectangular openings 211. For a certain busbar (e.g., the first busbar 21a), the number of openings 211 may be one, two or more, or the number of electrode fingers 22 connected to the second busbar 21b may be the same. This embodiment does not limit the number of openings.

[0136] exist Figure 10In the structure shown, between two adjacent electrode fingers connected to the same bus bar (such as the second bus bar 21b), there is an opening 211 in the second bus bar 21b in this area, and the notch of the opening 211 faces the second bus bar 21b. In one embodiment, the projection of the opening 211 in the extending direction of the electrode finger is the third projection, and the projection of the electrode finger located between the two adjacent electrode fingers and connected to the first bus bar 21a in the same direction is the fourth projection. The third projection and the fourth projection may partially overlap, so that the projection of the non-opening part of the second bus bar 21b in the same direction partially overlaps with the fourth projection; in another embodiment, the third projection and the fourth projection may not overlap at all, so that the fourth projection is located within the projection of the non-opening part of the second bus bar 21b in the same direction.

[0137] It can be understood that the third projection may be located on the left side or the right side of the fourth projection, which is not limited in the embodiments of the present application.

[0138] In the embodiments of the present application, by providing a rectangular opening in the bus bar 21, the third projection of the opening in the extending direction of the electrode finger does not overlap or partially overlaps with the fourth projection of the free end of the electrode finger in the same direction, so as to suppress the transverse mode, and while suppressing the gap mode, it can also suppress the spurious mode on the left side of the resonance point, thereby improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device.

[0139] The embodiments of the present application can further suppress the transverse mode, suppress the high-order gap mode, and improve the Q value by combining the base-end widening part, the load structure, the dummy fingers, the conductive strip, etc. on the basis of achieving the above effects. The relevant descriptions of the above structure can refer to the foregoing embodiments. Among them, the conductive strip is horizontally arranged in the bus bar area to divide each rectangular opening into at least two parts. Specifically, the extending direction of the conductive strip may be parallel or intersect with the extending direction of the bus bar, which will not be elaborated in the embodiments of the present application.

[0140] In a specific embodiment, the size of the opening 211 in the second direction is W3, 0 < W3 < 0.5λ, and specifically, it may be 0.1λ, 0.2λ, 0.3λ, 0.4λ, etc., to achieve non-overlap or partial overlap between the third projection and the fourth projection. In the present application, the size of the opening 211 can be finely adjusted according to requirements, so as to further improve the effect of suppressing the transverse mode, and while improving the suppression effect of the gap mode, it can also suppress the spurious mode on the left side of the resonance point, thereby improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device.

[0141] In another specific embodiment, the size of the opening in the extending direction of the electrode finger is L3, that is, the depth of the opening, 0.2λ < L3 < 5λ. The depth of the rectangular opening is limited within this range, and the third projection of the opening does not overlap or partially overlap with the fourth projection of the free end of the electrode finger, so as to be conducive to improving the lateral mode suppression effect, and while further improving the gap mode suppression effect, it is conducive to further suppressing the spurious modes on the left side of the resonance point of the elastic wave device, thereby improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device. If L3 is too large or too small, the amplitude of the lateral mode or the gap mode will become stronger.

[0142] Specifically, L3 can be 0.3λ, 0.5λ, 0.8λ, λ, 2λ, 3λ, 4λ, 4.9λ, etc., which are not limited in the embodiments of the present application.

[0143] In a preferred embodiment, 0.2λ < L3 < 3λ. Specifically, L3 can be 0.3λ, 0.6λ, 0.9λ, 1.2λ, 1.5λ, 2λ, 2.5λ, 2.9λ, etc., which is not only conducive to suppressing the lateral mode, the gap mode and the spurious modes on the left side of the resonance point, but also can realize the miniaturization of the device.

[0144] In yet another specific embodiment, in the extending direction of the electrode finger, the distance between the bus bar and the free end of the electrode finger is L4, that is, the distance between the bus bar of the part without the opening and the free end of the electrode finger, 0.1λ < L4 < 5λ. L4 is limited within this range, and the third projection of the opening does not overlap or partially overlap with the fourth projection of the free end of the electrode finger, so as to be conducive to improving the lateral mode suppression effect, and while further improving the gap mode suppression effect, it is conducive to further suppressing the spurious modes on the left side of the resonance point of the elastic wave device, thereby improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device.

[0145] Specifically, L4 can be 0.2λ, 0.5λ, 0.8λ, λ, 2λ, 3λ, 4λ, 4.9λ, etc., which are not limited in the embodiments of the present application.

[0146] In a preferred embodiment, 0.1λ < L4 < 3λ. Specifically, L4 can be 0.3λ, 0.6λ, 0.9λ, 1.2λ, 1.5λ, 2λ, 2.5λ, 2.9λ, etc.

[0147] In another embodiment, specifically, as Figure 11As shown, the elastic wave device provided in this application embodiment also includes: a piezoelectric substrate and interdigitated electrodes disposed on one side of the piezoelectric substrate. The interdigitated electrodes include two busbars 21 (e.g., a first busbar 21a and a second busbar 21b) spaced apart in a first direction, and a plurality of electrode fingers 22 located between the first busbar 21a and the second busbar 21b and spaced apart.

[0148] Electrode finger 22 includes a base end 221 and a free end 222. The base end 221 of any electrode finger 22 is connected to a bus bar, and the free end 222 extends to another bus bar and is spaced apart from the other bus bar. Electrode fingers connected to the first bus bar 21a and the second bus bar 21b are spaced apart and alternately arranged in a second direction, and the second direction intersects the first direction. Figure 11 In the structure shown, the second direction is orthogonal to the first direction.

[0149] The busbar 21 has at least one opening 211 on the side facing the free end of the electrode finger 22. The opening 211 has a third projection in the extension direction of the electrode finger 22. The free end 222 of the electrode finger connected to another busbar has a fourth projection in the extension direction of the electrode finger 22. The third projection is located within the fourth projection. The opening 211 is rectangular in shape and is axially symmetrical about the centerline of the electrode finger connected to the other busbar.

[0150] The embodiments of this application and Figure 10 The difference in the structure shown is that the third projection of the rectangular opening is located within the fourth projection of the free end of the electrode finger, and the opening is symmetrical about the centerline of the electrode finger. Therefore, the width of the opening is smaller than the width of the electrode finger, which helps to improve the transverse mode suppression effect. While improving the gap mode suppression effect, it also helps to suppress the miscellaneous modes on the left side of the resonant point of the elastic wave device, thereby improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device.

[0151] It should be noted that other structures of the elastic wave device provided in this application embodiment are as follows: Figure 10 The relevant descriptions of the corresponding embodiments will not be repeated in this application.

[0152] Please see Figure 12 , Figure 13 as well as Figure 18 , Figure 12 and Figure 13 This is a comparison diagram of the effects of the embodiments of this application and related technology 1. The embodiments of this application are... Figure 3 The structure shown has a base widening portion on each electrode finger, and the electrode fingers are widened in the edge region; related technology 1 is Figure 18The structure shown in (a) has the same widening of the electrode fingers only in the edge region, the same mass load for both, and the same other structural parameters for both. Figure 12 and Figure 13 In the diagram, the solid lines represent embodiments of this application, and the dashed lines represent related technologies 1.

[0153] Figure 12 This is a schematic diagram comparing the admittance curves of the embodiments of this application and related technology 1. Figure 12 In the figure, (a) is a comparison of admittance curves, and (b) is a comparison of real part admittance curves. The horizontal axis represents frequency in GHz, and the vertical axis represents admittance in dB. To facilitate comparison on the same coordinate axis, the vertical axis of related technology 1 is shifted upward by 10 dB. Figure 12 (Especially the elliptical dashed box in figure (b)) It can be seen that in related technology 1, simply setting a load structure cannot completely suppress transverse modes. However, the embodiments of this application, under the same load structure, can better suppress transverse modes and can also effectively suppress higher-order gap modes and miscellaneous modes to the left of the resonance point.

[0154] Figure 13 This is a schematic diagram comparing the Bode Q curves of the embodiments of this application and related technology 1. Figure 13 It can be seen that the Q value of the embodiments of this application is greatly improved.

[0155] Please see Figure 14 , Figure 15 as well as Figure 18 , Figure 14 and Figure 15 This is a comparison diagram of the effects of the embodiments of this application and related technology 2. The embodiments of this application are... Figure 3 The structure shown has a base widening portion on each electrode finger, and the electrode fingers are widened in the edge region; related technology 2 is Figure 18 The structure shown in (b) has the same widening of the electrode fingers in the edge region, the same mass load for both, and a conductive strip is provided in the gap region. All other structural parameters are the same for both. The solid line represents the embodiment of this application, and the dashed line represents related technology 2. Figure (a) is a comparison diagram of admittance curves, and Figure (b) is a comparison diagram of the real part of the admittance curves. The horizontal axis represents frequency in GHz, and the vertical axis represents admittance in dB. To facilitate comparison on the same coordinate axis, the vertical axis of related technology 2 is shifted upwards by 10 dB. Figure 14 (Especially the elliptical dashed box in figure (b)) It can be seen that both related technology 2 and the embodiments of this application can suppress the transverse modes well, but the suppression effect of the embodiments of this application is better than that of related technology 2. In related technology 2, there are still clutter modes on the left side of the resonance point, and the higher-order gap modes are not well suppressed, while the embodiments of this application can suppress the higher-order gap modes well and have a better suppression effect on the clutter modes on the left side of the resonance point.

[0156] Figure 15 This is a schematic diagram comparing the Bode Q curves of the embodiments of this application and related technology 2. Figure 15 It can be seen that the Q value of this embodiment is significantly improved, and the Q value curve is smoother than that of related technology 2.

[0157] Please see Figure 16 , Figure 17 as well as Figure 18 , Figure 16 and Figure 17 This is a comparison diagram of the effects of the embodiments of this application and related technology 3. The embodiments of this application are... Figure 3 The structure shown has a base widening portion on each electrode finger, and the electrode fingers are widened in the edge region, making the electrode fingers straight; related technology 3 is Figure 18 The structure shown in (c) has the same widening of the electrode fingers in the edge region, and both have the same mass load. The electrode fingers are bent electrode fingers, and all other structural parameters are the same. The solid line represents the embodiment of this application, and the dashed line represents related technology 3. Figure (a) is a comparison diagram of admittance curves, and Figure (b) is a comparison diagram of the real part of admittance curves. The horizontal axis represents frequency in GHz, and the vertical axis represents admittance in dB. To facilitate comparison on the same coordinate axis, the vertical axis of related technology 3 is shifted upwards by 10 dB. Figure 16 (Especially the elliptical dashed box in figure (b)) It can be seen that both related technology 3 and the embodiments of this application can suppress the transverse modes well, but the suppression effect of the embodiments of this application is better than that of related technology 3. In related technology 3, there are still clutter modes on the left side of the resonance point, and the higher-order gap modes are not well suppressed, while the embodiments of this application can suppress the higher-order gap modes well and have a better suppression effect on the clutter modes on the left side of the resonance point.

[0158] Figure 17 This is a schematic diagram comparing the Bode Q curves of the embodiments of this application and related technology 3. Figure 15 It can be seen that the resonant point Q value and Qmax of the embodiments of this application are greatly improved.

[0159] This application also provides a radio frequency (RF) front-end module, which includes an antenna, a switch, an amplifier, and a duplexer (or multiplexer). The antenna is used to receive external signals or transmit RF signals. The switch is located between the antenna and the duplexer (or multiplexer) to control signal transmission between them. When the amplifier is a low-noise amplifier, when the switch is closed, the duplexer (or multiplexer) filters the external signal received by the antenna and outputs a signal with a preset frequency to the low-noise amplifier. When the amplifier is an RF power amplifier, when the switch is closed, the duplexer (or multiplexer) filters the RF signal amplified by the RF power amplifier and outputs an RF signal with a preset frequency to the antenna, which then transmits the RF signal.

[0160] In one embodiment, the duplexer (or multiplexer) may be an elastic wave device as described above, or may include an elastic wave device as described above.

[0161] The radio frequency front-end module provided in this application includes the elastic wave device provided in the aforementioned embodiments. By providing a base end widening portion on the electrode fingers, and the base end widening portion at least partially overlaps with the projection of the free end of the adjacent electrode fingers in the extension direction of the electrode fingers, or by opening the bus bar with a rectangular opening such that the unopened portion at least partially overlaps with the projection of the free end of the electrode fingers in the extension direction of the electrode fingers, the suppression effect of transverse modes can be improved. In addition to improving the suppression effect of gap modes, it can also suppress the clutter modes on the left side of the resonant point of the elastic wave device, thereby improving the Q value of the elastic wave device and enhancing the working performance of the elastic wave device.

[0162] This application also provides an electronic device, which includes a substrate and a radio frequency (RF) front-end module mounted on the substrate. The substrate and the RF front-end module are electrically connected. The RF front-end module includes the elastic wave device provided in the foregoing embodiments.

[0163] In one embodiment, the substrate is a printed circuit board to enable operational control of the radio frequency (RF) front-end module. The electronic device of this application utilizes the RF front-end module to receive and / or transmit signals.

[0164] For example, electronic devices may be computers, mobile phones, tablets, smartwatches, vehicle terminals, and navigation devices that need to receive and / or transmit radio frequency signals, and this application does not limit them.

[0165] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An elastic wave device, characterized in that, Comprising: A piezoelectric substrate and interdigital electrodes provided on one side of the piezoelectric substrate. The interdigital electrodes include at least two bus bars spaced apart in a first direction, and a plurality of electrode fingers located between and spaced apart from adjacent bus bars; The electrode fingers include a base end and a free end. The base end of any one of the electrode fingers is connected to one of the bus bars, and the free end extends towards the other bus bar and is spaced apart from the other bus bar; The electrode fingers connected to different bus bars are spaced apart and alternately arranged in a second direction, and the second direction intersects with the first direction; The plurality of electrode fingers include a first electrode finger and a second electrode finger adjacent to the first electrode finger. The second electrode finger is one of the two electrode fingers adjacent to the first electrode finger; The base end of the first electrode finger and the base end of the second electrode finger are connected to different bus bars, and the first electrode finger is any one of the plurality of electrode fingers; Wherein, the base end of the first electrode finger is provided with a base end widening portion. The base end widening portion includes the base end and an extension portion. The extension portion extends from one of the two side edges of the base end in the second direction in the second direction. The side edge of the base end widening portion facing away from the free end is connected to the bus bar. The base end widening portion is electrically connected to the bus bar. The base end widening portion has a first projection in the extending direction of the electrode finger. The free end of the second electrode finger has a second projection in the extending direction of the electrode finger. The second projection is located within the first projection; The dimension of the base end widening portion in the second direction is W1, and the W1 of all electrode fingers connected to the same bus bar is the same; The dimension of the base end widening portion in the extending direction of the electrode finger is L1, and the L1 of all electrode fingers connected to the same bus bar is the same.

2. The elastic wave device according to claim 1, characterized in that, The dimension of the base end widening portion in the second direction is W1, 0.5λ < W1 < λ, where λ is the acoustic wave wavelength of the elastic wave device.

3. The elastic wave device according to claim 1, characterized in that, The dimension of the base end widening portion in the extending direction of the electrode finger is L1, 0.2λ < L1 < 5λ; and / or, In the extending direction of the electrode finger, the distance between the base end widening portion and the free end of the second electrode finger is L2, 0.1λ < L2 < 5λ; Wherein, λ is the acoustic wave wavelength of the elastic wave device.

4. The elastic wave device according to claim 3, characterized in that, 0.2λ < L1 < 3λ; and / or, 0.1λ < L2 < 3λ.

5. The elastic wave device according to claim 1, characterized in that, The projection of the base end widening portion on the piezoelectric substrate is rectangular.

6. The elastic wave device according to claim 1, characterized in that, The interdigital electrodes further include dummy fingers. One end of the dummy finger is connected to the base end widening portion. The other end of the dummy finger faces the free end of the second electrode finger and is spaced apart from the free end of the second electrode finger.

7. The elastic wave device according to claim 6, characterized in that, The dimension of the base end widening portion in the second direction is W1, the distance between the midlines of adjacent two electrode fingers is P, the duty ratio of the electrode finger is DF, (1 + DF)*P < W1 < λ, where 2P = λ, where λ is the acoustic wave wavelength of the elastic wave device.

8. The elastic wave device according to claim 6, characterized in that, The pseudo-finger of a plurality of first electrode fingers connected to the same busbar has the same dimension in the extension direction of the electrode finger; or, The dummy fingers of the plurality of first electrode fingers connected to the same busbar have different dimensions in the extension direction of the electrode fingers to form an apodization pattern.

9. The elastic wave device according to claim 1, characterized in that, The first electrode finger is any one of the plurality of electrode fingers. The interdigitated electrode further includes a conductive strip, which is connected to the base end widening portion of the plurality of first electrode fingers connected to the same busbar. In the extension direction of the electrode finger, the distance D1 between the conductive strip and the side of the base end widening portion near the free end of the second electrode finger is greater than 0, and the distance D2 between the conductive strip and the busbar is greater than 0.

10. The elastic wave device according to claim 9, characterized in that, The elastic wave device includes at least one of the following: The dimension W2 of the conductive strip in the extension direction of the electrode finger satisfies [0.1λ, 0.4λ]; 0.1λ <D1<2.5λ; 0.1λ <D2<2.5λ; Wherein, λ is the acoustic wavelength of the elastic wave device.

11. The elastic wave device according to claim 1, characterized in that, In the extension direction of the electrode finger, the distance between the base widened portion and the free end of the second electrode finger is L2, and the distance L2 is the same for multiple first electrode fingers connected to the same busbar.

12. The elastic wave device according to claim 1, characterized in that, In the extension direction of the electrode finger, the distance between the base widened portion and the free end of the second electrode finger is L2. The distance L2 of multiple first electrode fingers connected to the same busbar is different to form an apodization pattern.

13. The elastic wave device according to claim 1, characterized in that, In the thickness direction of the piezoelectric substrate, the thickness of the base end widening portion is H1, and the thickness of the electrode finger is H2, where H2≤H1≤1.8H2.

14. The elastic wave device according to claim 1, characterized in that, The electrode fingers connected to different busbars are alternately arranged in a second direction to form an alternating region; in the extension direction of the electrode fingers, the alternating region includes a middle region and edge regions located on both sides of the middle region; the interdigitated electrode also includes a load structure disposed in the edge region.

15. The elastic wave device according to claim 1, characterized in that, The piezoelectric substrate includes a piezoelectric layer, and the interdigitated electrodes are disposed on one side of the piezoelectric layer; or, The piezoelectric substrate includes a substrate and a piezoelectric layer stacked together, and the interdigitated electrodes are disposed on the side of the piezoelectric layer away from the substrate.

16. The elastic wave device according to claim 15, characterized in that, The elastic wave device further includes a temperature compensation layer, which is disposed on one side of the piezoelectric substrate and covers the interdigitated electrodes.

17. An elastic wave device, characterized in that, include: The piezoelectric substrate and the interdigitated electrode disposed on one side of the piezoelectric substrate, the interdigitated electrode including at least two busbars spaced apart in a first direction, and a plurality of electrode fingers located between adjacent busbars and spaced apart; The electrode finger includes a base end and a free end. The base end of any electrode finger is connected to one of the bus bars, and the free end extends to another bus bar and is spaced apart from the other bus bar. The electrode fingers connected to different bus bars are spaced apart and alternately arranged in a second direction, which intersects the first direction. At least one opening is provided on a side of the bus bar facing the free end of the electrode finger. The shape of the opening is rectangular. The opening has a third projection in the extending direction of the electrode finger. The free end of the electrode finger connected to another bus bar has a fourth projection in the extending direction of the electrode finger. The third projection and the fourth projection do not overlap or partially overlap. The plurality of electrode fingers include a first electrode finger and a second electrode finger adjacent to the first electrode finger. The second electrode finger is one of the two electrode fingers adjacent to the first electrode finger. The first electrode finger is any one of the plurality of electrode fingers. Among them, the first electrode finger is provided with a base end widening portion. The base end widening portion includes the base end and an extending portion. The extending portion extends from one of the two side edges of the base end in the second direction in the second direction. The side edge of the base end widening portion facing away from the free end is connected to the bus bar. The base end widening portion is electrically connected to the bus bar. The base end widening portion has a first projection in the extending direction of the electrode finger. The free end of the second electrode finger has a second projection in the extending direction of the electrode finger. The second projection is located within the first projection. The dimension of the base end widening portion in the second direction is W1, and the W1 of all the electrode fingers connected to the same bus bar is the same. The dimension of the base end widening portion in the extending direction of the electrode finger is L1, and the L1 of all the electrode fingers connected to the same bus bar is the same.

18. The elastic wave device according to claim 17, characterized in that, The elastic wave device includes at least one of the following: The dimension of the opening in the second direction is W3, and 0 < W3 < 0.5λ. The dimension of the opening in the extending direction of the electrode finger is L3, and 0.2λ < L3 < 5λ. In the extending direction of the electrode finger, the distance between the bus bar and the free end of the electrode finger is L4, and 0.1λ < L4 < 5λ. Among them, λ is the acoustic wave wavelength of the elastic wave device.

19. The elastic wave device according to claim 18, characterized in that, 0.2λ < L3 < 3λ; and / or, 0.1λ ≤ L4 < 3λ.

20. An elastic wave device, characterized in that, Including: A piezoelectric substrate and interdigital electrodes provided on one side of the piezoelectric substrate. The interdigital electrodes include two bus bars spaced apart in a first direction, and a plurality of electrode fingers located between adjacent bus bars and arranged at intervals. The electrode fingers include a base end and a free end. The base end of any one of the electrode fingers is connected to one bus bar. The free end extends toward the other bus bar and is spaced apart from the other bus bar. The electrode fingers connected to different bus bars are spaced apart and alternately arranged in a second direction. The second direction intersects with the first direction. At least one opening is provided on a side of the bus bar facing the free end of the electrode finger. The opening has a third projection in the extending direction of the electrode finger. The free end of the electrode finger connected to another bus bar has a fourth projection in the extending direction of the electrode finger. The third projection is located within the fourth projection. The shape of the opening is rectangular. The opening is axially symmetrically arranged with the midline of the electrode finger connected to the other bus bar as the axis of symmetry. The plurality of electrode fingers includes a first electrode finger and a second electrode finger adjacent to the first electrode finger, wherein the second electrode finger is one of the two electrode fingers adjacent to the first electrode finger, and the first electrode finger is any one of the plurality of electrode fingers; The first electrode finger has a base end widening portion, which includes the base end and an extension portion. The extension portion extends from one of the two sides of the base end in the second direction toward the second direction. The side of the base end widening portion away from the free end is connected to the bus bar. The base end widening portion is electrically connected to the bus bar. The base end widening portion has a first projection in the extension direction of the electrode finger. The free end of the second electrode finger has a second projection in the extension direction of the electrode finger. The second projection is located within the first projection. The base end widening portion has a dimension of W1 in the second direction, and the W1 of all electrode fingers connected to the same busbar is the same; the base end widening portion has a dimension of L1 in the extension direction of the electrode finger, and the L1 of all electrode fingers connected to the same busbar is the same.

21. A radio frequency front-end module, characterized in that, Includes the elastic wave device as described in any one of claims 1-20.

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