A surface acoustic wave device, filter device, and multiplexer

Abstract

The application discloses a surface acoustic wave device, a filter device and a multiplexer. The surface acoustic wave device comprises: a piezoelectric substrate; an electrode layer arranged on the surface of the piezoelectric substrate; the electrode layer comprises a bus bar and an interdigital transducer electrode; the interdigital transducer electrode comprises a plurality of electrode fingers arranged in parallel and staggered in a first direction, and the electrode fingers extend along a second direction; the bus bar is arranged in parallel at both ends of the interdigital transducer electrode in the second direction, and the bus bar is connected with the adjacent electrode finger; the second direction intersects the first direction; wherein at least two hollow structures are arranged on each electrode finger, and the at least two hollow structures are arranged periodically and spaced apart in the second direction. The embodiment of the application can effectively suppress the transverse mode of the surface acoustic wave device and improve the overall performance of the surface acoustic wave device.

Description

Technical Field

[0001] This invention relates to the field of surface acoustic wave (SAW) technology, and more particularly to a SAW device, a filter device, and a multiplexer. Background Technology

[0002] Surface acoustic wave (SAW) devices are electronic components that utilize the propagation characteristics of sound waves on the surface of piezoelectric materials. They are widely used in filters, resonators, and other fields.

[0003] However, existing surface acoustic wave (SAW) devices still suffer from a common problem in the sound wave propagation process: the existence of a transverse mode. This leads to energy loss, suboptimal frequency response, and signal distortion, which in turn affects the overall performance of the SAW device. Summary of the Invention

[0004] This invention provides a surface acoustic wave (SAW) device, a filter device, and a multiplexer to effectively suppress the transverse mode of the SAW device and improve the overall performance of the SAW device.

[0005] According to a first aspect of the present invention, a surface acoustic wave device is provided, comprising: piezoelectric substrate; An electrode layer is disposed on the surface of the piezoelectric substrate; the electrode layer includes a busbar and interdigitated transducer electrodes; the interdigitated transducer electrodes include a plurality of electrode fingers arranged parallel and staggered in a first direction, and the electrode fingers extend along a second direction; the busbar is disposed parallel to both ends of the interdigitated transducer electrodes in the second direction, and the busbar is connected to the adjacent electrode fingers; the second direction intersects the first direction; Each of the electrode fingers is provided with at least two hollow structures, and in the second direction, the at least two hollow structures are arranged at periodic intervals.

[0006] Optionally, each of the electrode fingers is provided with at least two gap columns, and each of the gap columns is provided with at least two hollow structures; At least two of the gap columns are arranged parallel and spaced apart in a direction perpendicular to the second direction, and a plurality of the hollow structures in the gap columns are arranged in an array.

[0007] Optionally, the hollow structure has a first width in the direction perpendicular to the second direction, and the electrode finger has a second width; wherein, the first width is the sum of the widths of each hollow structure in the electrode finger in the direction perpendicular to the second direction; The first width and the second width have a first ratio; the first ratio is greater than or equal to 0.125 and less than 1.

[0008] Optionally, in the thickness direction of the piezoelectric substrate, each of the electrode fingers in the electrode layer has a predetermined thickness; The preset thickness has a second ratio to the wavelength of the surface acoustic wave, and the second width has a third ratio to the first width; The second ratio is greater than or equal to 6% of the third ratio, and the second ratio is less than or equal to 12% of the third ratio.

[0009] Optionally, the orthographic projection shape of the hollow structure on the surface of the piezoelectric substrate includes any one of rectangle, circle and triangle.

[0010] Optionally, the interdigital transducer electrode includes a first electrode group and a second electrode group, wherein the first electrode group includes a plurality of first electrode fingers arranged in parallel, and the second electrode group includes a plurality of second electrode fingers arranged in parallel; the plurality of first electrode fingers and the plurality of second electrode fingers are arranged in an interlaced manner. The busbar includes a first busbar and a second busbar, and a plurality of first electrode fingers are electrically connected to the first busbar, and a plurality of second electrode fingers are electrically connected to the second busbar.

[0011] Optionally, in the first direction, reflectors are respectively provided on both sides of the interdigital transducer electrode; The reflector includes a reflector busbar and a plurality of reflector electrodes, the reflector electrodes extending along the second direction, and the plurality of reflector electrodes being arranged in parallel in the first direction; In the second direction, a reflector busbar is provided at each end of the reflector electrode, and both ends of the reflector electrode are electrically connected to the reflector busbar.

[0012] Optionally, the piezoelectric substrate includes a substrate, a trapping material layer, a low-velocity layer, and a piezoelectric thin film layer stacked together. The electrode layer is disposed on the surface of the piezoelectric thin film layer away from the substrate.

[0013] According to a second aspect of the present invention, a filter device is provided, comprising: Series arm resonators; and, Parallel arm resonator; Wherein, at least one of the series arm resonator and the parallel arm resonator is a surface acoustic wave device as described in any embodiment of the first aspect.

[0014] According to a third aspect of the present invention, a multiplexer is provided, comprising: Antenna terminals, electrically connected to the antenna; and, Multiple filtering units are all communicatively connected to the antenna terminal; Wherein, at least one of the filtering units is a filter device as described in the second aspect embodiment.

[0015] The surface acoustic wave (SAW) device provided in this invention comprises an electrode layer disposed on the piezoelectric substrate having piezoelectric properties. The electrode layer includes busbars and interdigitated transducer electrodes. Multiple electrode fingers of the interdigitated transducer electrodes are arranged parallel and staggered in a first direction, and extend in a second direction. Two busbars extending along the first direction are disposed parallel to each other at both ends of the interdigitated transducer electrodes in the second direction, and the busbars are electrically connected to all correspondingly adjacent electrode fingers. At least two hollow structures are disposed on each electrode finger of the interdigitated transducer electrodes, and the at least two hollow structures are periodically spaced in the second direction, exposing the piezoelectric substrate located below the electrode layer. Compared to the multiple flat, elongated electrode fingers arranged in a forked pattern in related technologies, the present invention provides a periodically arranged hollow structure on the surface of the electrode fingers. This allows the horizontal shear wave slowness curve obtained by the surface acoustic wave device to exhibit a concave state at Sx=0, ensuring that the curvature of the slowness curve of the surface acoustic wave device is less than 0. This effectively suppresses the transverse mode of the surface acoustic wave device and helps improve the overall performance of the surface acoustic wave device.

[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a top view of a surface acoustic wave device provided by related technologies; Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure along the A-A' direction; Figure 3 yes Figure 1 A schematic diagram of the cross-sectional structure along the B-B' direction; Figure 4 This is an admittance / conductance-frequency curve diagram of a surface acoustic wave device provided by related technologies; Figure 5This is another surface acoustic wave device's admittance / conductance-frequency curve provided by related technologies; Figure 6 This is a horizontal shear wave slowness curve diagram of a surface acoustic wave device provided by related technologies; Figure 7 This is a horizontal shear wave slowness curve diagram of another surface acoustic wave device provided by related technologies; Figure 8 This is a top view schematic diagram of a surface acoustic wave device according to an embodiment of the present invention; Figure 9 This is a top view of another surface acoustic wave device provided according to an embodiment of the present invention; Figure 10 This is a horizontal shear wave slowness curve of a surface acoustic wave device according to an embodiment of the present invention, which varies with a first ratio. Figure 11 This is a graph showing the curvature of the horizontal shear wave slowness curve of a surface acoustic wave device according to an embodiment of the present invention as a function of a first ratio. Figure 12 yes Figure 8 A schematic diagram of the cross-sectional structure along the C-C' direction; Figure 13 This is a comparison curve of the slowness curve curvature of a surface acoustic wave device according to an embodiment of the present invention as a function of a second ratio; Figure 14 This is a top view of another surface acoustic wave device provided according to an embodiment of the present invention; Figure 15 This is a top view of another surface acoustic wave device provided according to an embodiment of the present invention; Figure 16 This is a schematic diagram of a filter device according to an embodiment of the present invention; Figure 17 This is a schematic diagram of a filter device according to an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] As described in the background section, in recent years, surface acoustic wave devices based on piezoelectric substrates have gained widespread attention due to their high Q-value performance and have been applied in many fields such as radar, communication, and navigation. Figure 1 This is a top view of a surface acoustic wave device provided by related technologies. Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure along the A-A' direction. Figure 3 yes Figure 1 A schematic diagram of the cross-sectional structure along the B-B' direction. (See also...) Figures 1 to 3 The surface acoustic wave (SAW) device 000 comprises an electrode layer formed on a piezoelectric substrate 001. Further, the electrode layer includes interdigital transducer (IDT) electrodes 002, reflector electrodes 003, interdigital transducer busbars 004, and reflector busbars 005. The thickness of the electrode layer can be represented by h. The IDT electrodes 002 include multiple first electrode fingers and multiple second electrode fingers interleaved with each other. The IDT busbars 004 include first and second busbars facing each other in the extension direction of the first and second electrode fingers. The distance between adjacent first electrode fingers or adjacent second electrode fingers is typically referred to as the "wavelength" of the IDT. The overlap distance between the first and second electrode fingers, denoted by d, is typically referred to as the "aperture" of the IDT. The reflector electrode 003 includes multiple third electrode fingers and multiple fourth electrode fingers inserted alternately. The reflector bus bar 005 includes a third bus bar and a fourth bus bar that are opposite each other in the extension direction of the third electrode fingers and the extension direction of the fourth electrode fingers.

[0022] The transverse modes present in surface acoustic wave (SAW) devices refer to the fluctuations between the resonant frequency and the anti-resonant frequency of the resonator, usually caused by diffraction during sound wave propagation. Admittance is a physical quantity describing the response of a circuit element to alternating current and voltage, usually denoted by the symbol Y. The admittance Y of a circuit element is equal to the ratio of its conductance G to its susceptance B, expressed in dB, i.e., Y = G + jB, where j represents the imaginary unit.

[0023] Figure 4 This is an admittance / conductance-frequency curve diagram of a surface acoustic wave device provided by related technologies. See also... Figure 4 The horizontal axis represents frequency in MHz; the vertical axis represents the ratio of admittance to conductance in dB. Curve 01 represents the admittance curve, and curve 02 represents the conductance curve. The conductance curves show significant fluctuations between the resonant and anti-resonant frequencies of the surface acoustic wave device 000. Figure 4 The curve segment between the highest and lowest points in curve 02 exhibits numerous fluctuations. This indicates that the surface acoustic wave device 000 possesses a transverse mode. Figure 5 This is another admittance / conductance-frequency curve provided by related technologies for a surface acoustic wave device. See also... Figure 5 In the figure, curve 03 represents the admittance curve, and curve 04 represents the conductance curve. The conductance curve shows that there is no fluctuation between the resonant frequency and the anti-resonant frequency of the surface acoustic wave (SAW) device, indicating that this is the conductance curve of a SAW device without a transverse mode.

[0024] Figure 6 This is a horizontal shear wave slowness curve diagram of a surface acoustic wave device provided by related technologies. See also... Figure 6 The curve at S x The point = 0 is convex, which indicates that the curvature of the slow curve of the surface acoustic wave device 000 is greater than 0, indicating that the surface acoustic wave device 000 has a transverse mode. Figure 7 This is a horizontal shear wave slowness curve diagram for another surface acoustic wave device provided by related technologies. See also... Figure 7 The curve at S x The point = 0 is concave, indicating that the curvature of the slowness curve of the surface acoustic wave device is less than 0. This means that this is the slowness curve of the horizontal shear wave of a surface acoustic wave device that does not have a transverse mode.

[0025] The presence of transverse modes in surface acoustic wave (SAW) devices can lead to problems such as energy loss, suboptimal frequency response, and signal distortion, thus affecting the overall performance of the SAW device.

[0026] Based on the above-mentioned technical problems, the embodiments of the present invention propose the following technical solutions: This invention provides a surface acoustic wave device. Figure 8 This is a top view schematic diagram of a surface acoustic wave device provided in an embodiment of the present invention. Figure 8 As shown, the surface acoustic wave device 00 includes: Piezoelectric substrate 100; An electrode layer 200 is disposed on the surface of a piezoelectric substrate 100. The electrode layer 200 includes a busbar 201 and interdigitated transducer electrodes 202. The interdigitated transducer electrodes 202 include a plurality of electrode fingers arranged parallel and staggered in a first direction, and the electrode fingers extend along a second direction. The busbar 201 is disposed parallel to both ends of the interdigitated transducer electrodes 202 in the second direction, and the busbar 201 is connected to the adjacent electrode fingers. The second direction intersects the first direction. Each electrode finger is provided with at least two hollow structures 203, and in the second direction, the at least two hollow structures 203 are arranged at periodic intervals.

[0027] Specifically, the surface acoustic wave (SAW) device 00 is formed by depositing an electrode layer 200 on the piezoelectric side of a piezoelectric substrate 100. The electrode layer 200 includes busbars 201 and interdigital transducer electrodes 202, i.e., IDT electrodes. Each interdigital transducer electrode 202 has multiple elongated electrode fingers extending along a second direction. These multiple electrode fingers are spaced parallel to each other in a first direction and are arranged in a staggered pattern to form an interdigitated electrode distribution. The first direction is also the direction of sound wave propagation in the SAW device 00. The first direction intersects the second direction. Exemplarily, the first and second directions can be perpendicular; the first direction can be the X direction and the second direction the Y direction; or, the first direction can be the Y direction and the second direction the X direction, without limitation. In this embodiment of the invention, see... Figure 8 Taking the first direction as the X direction and the second direction as the Y direction as an example, the interdigital transducer electrode 202 includes busbars 201 arranged opposite each other along the extension direction of the electrode fingers, with the interdigital transducer electrode 202 positioned between the two busbars 201. The two busbars 201 extend along the first direction and are electrically connected to all the electrode fingers of the interdigital transducer electrode 202 on the adjacent side, enabling input or output, convergence, and distribution of electrical signals to the interdigital transducer electrode 202. They also mechanically fix the numerous electrode fingers in the interdigital transducer electrode 202 and assist in heat dissipation.

[0028] At least two hollow structures 203 are provided on each electrode finger of the interdigital transducer electrode 202. The hollow structure 203 is formed by etching at least two hollow structures 203 on each elongated electrode finger, which is made of a conductive metallic material, such as aluminum, exposing the piezoelectric substrate 100 located below the electrode layer 200. On each electrode finger, at least two hollow structures 203 are periodically arranged in the second direction Y, that is, arranged in at least one column in the second direction Y. For example, see [reference needed]. Figure 8 This illustrates a case where a series of periodically arranged perforated structures 203 are provided on the surface of each electrode finger. Compared to the complete metal strip-shaped electrode fingers formed in related technologies, this embodiment of the invention, by providing at least two periodically spaced perforated structures 203 on the surface of each electrode finger in the interdigital transducer electrode 202, allows the horizontal shear wave slowness curve obtained by testing the fabricated surface acoustic wave device 00 to be more stable in the S... x The point = 0 exhibits a concave state, thus ensuring that the curvature of the slowness curve of the surface acoustic wave (SAW) device 00 is less than 0. The curvature of the slowness curve, represented by γ, can predict, to some extent, the transverse mode generated by the SAW device. When the curvature of the slowness curve is greater than 0, the SAW device typically generates a transverse mode; when the curvature of the slowness curve is less than 0, the SAW device typically does not generate a transverse mode. This demonstrates that, in this embodiment of the invention, the periodically spaced at least two hollow structures 203 on the surface of each electrode finger in the interdigital transducer electrode 202 effectively suppresses the transverse mode formed in the SAW device 00, thereby improving the overall performance of the SAW device 00.

[0029] The surface acoustic wave (SAW) device provided in this embodiment of the invention comprises an electrode layer 200 disposed on the piezoelectric substrate 100 having piezoelectric properties. The electrode layer includes busbars 201 and interdigitated transducer electrodes 202. Multiple electrode fingers of the interdigitated transducer electrodes 202 are arranged parallel and staggered in a first direction X, and extend in a second direction Y. Two busbars 201 extending along the first direction X are disposed parallel to each other at both ends of the interdigitated transducer electrodes 202 in the second direction Y, and the busbars 201 are electrically connected to all correspondingly adjacent electrode fingers. At least two perforated structures 203 are disposed on each electrode finger of the interdigitated transducer electrodes 202, and the at least two perforated structures 203 are periodically spaced in the second direction Y, exposing the piezoelectric substrate 100 located below the electrode layer 200. Compared to the multiple flat, elongated electrode fingers arranged in an interdigitated pattern in related technologies, the present invention provides a periodically arranged hollow structure 203 on the surface of the electrode fingers. This allows the horizontal shear wave slowness curve obtained by the surface acoustic wave device 00 to exhibit a concave state at Sx=0, ensuring that the curvature of the slowness curve of the surface acoustic wave device 00 is less than 0. This effectively suppresses the transverse mode of the surface acoustic wave device 00 and improves the overall performance of the surface acoustic wave device 00.

[0030] Based on the above embodiments, see below. Figure 8 Optionally, the interdigital transducer electrode 202 includes a first electrode group 205 and a second electrode group 206. The first electrode group 205 includes a plurality of first electrode fingers 207 arranged in parallel, and the second electrode group 206 includes a plurality of second electrode fingers 208 arranged in parallel. The plurality of first electrode fingers 207 and the plurality of second electrode fingers 208 are arranged in an interlaced manner. Busbar 201 includes a first busbar 209 and a second busbar 210. Multiple first electrode fingers 207 are electrically connected to the first busbar 209, and multiple second electrode fingers 208 are electrically connected to the second busbar 210.

[0031] Specifically, multiple first electrode fingers 207 and multiple second electrode fingers 208 are arranged alternately and at intervals in the first direction X, and are arranged in a cross-finger shape. Among them, the first electrode fingers 207 located on the same side are all electrically connected to the first bus bar 209, and the second electrode fingers 208 located on the same side are all electrically connected to the second bus bar 210. Thus, through the first bus bar 209 and the second bus bar 210, the input or output, convergence and distribution of electrical signals of the interdigital transducer electrodes 202 are realized.

[0032] Based on the above embodiments, Figure 9 This is a top view schematic diagram of another surface acoustic wave device provided in an embodiment of the present invention. See also Figure 9Optionally, each electrode finger is provided with at least two gap columns 204, and each gap column 204 is provided with at least two hollow structures 203; At least two gap columns 204 are arranged parallel and spaced apart in a direction perpendicular to the second direction Y, and multiple hollow structures 203 in the gap columns 204 are arranged in an array.

[0033] Specifically, at least two rows of hollow structures 203 can be provided on the surface of each electrode finger in the interdigital transducer electrode 202. That is, the electrode finger surface includes at least two rows of gaps 204, adjacent rows of gaps 204 are spaced apart in the first direction X, and each row of gaps 204 contains the same number of periodically arranged hollow structures 203. For example, see Figure 9 This illustrates a configuration where each electrode finger has two gap columns 204, and each gap column 204 has five hollow structures 203. By providing hollow structures 203 in at least two gap columns 204, the horizontal shear wave slowness curve of the fabricated surface acoustic wave device 00 can also be measured in S... x The point = 0 is concave, which makes the curvature of the slow curve of the surface acoustic wave device 00 less than 0, thereby ensuring that the surface acoustic wave device 00 does not have a transverse mode and effectively improving the overall performance of the surface acoustic wave device 00.

[0034] Based on the above embodiments, see below. Figure 8 Optionally, in the direction perpendicular to the second direction Y, the hollow structure 203 has a first width G, and the electrode finger has a second width W; wherein, the first width G is the sum of the widths of each hollow structure 203 in the electrode finger in the direction perpendicular to the second direction Y; There is a first ratio between the first width G and the second width W; the first ratio is greater than or equal to 0.125 and less than 1.

[0035] Specifically, the width ratio of the hollow structure 203 on each electrode finger needs to reach a certain value to better suppress the transverse mode of the surface acoustic wave device 00. For example, the first ratio obtained by dividing the first width G of the hollow structure 203 by the second width W of the electrode finger needs to be greater than or equal to 0.125, and ensure that the first ratio is less than 1. That is, when the first ratio is within the range of [0.125, 1), the curvature of the slowness curve of the surface acoustic wave device 00 can be guaranteed to be less than 0, thereby effectively suppressing the transverse mode generated by the surface acoustic wave device 00. It should be noted that, see [reference needed]. Figure 8 and Figure 9 The first width G of the hollow structure 203 is the sum of the widths of at least two hollow structures 203 in the first direction X among the at least two gap columns 204 provided on an electrode finger. Figure 10This is a horizontal shear wave slowness curve of a surface acoustic wave device provided in an embodiment of the present invention, varying with a first ratio. See also... Figure 10 Curves 11 to 16 represent the horizontal shear wave slowness curves corresponding to first ratios of 0, 0.125, 0.25, 0.4, 0.45, and 0.5, respectively. Figure 10 It can be seen that when the first ratio is 0, i.e., G / W = 0, the slowness curve of the surface acoustic wave device 00 is at S x If the curve is convex at point = 0, it indicates that the curvature of the slow curve is greater than 0, and the surface acoustic wave device 000 exhibits a transverse mode; however, when G / W ≥ 0.125, the slow curve at S... x The indentation at point =0 becomes increasingly apparent, indicating that the curvature of the slow curve is less than 0, and the surface acoustic wave device 000 does not exhibit a transverse mode. Furthermore, the larger the value of the first ratio G / W, the smaller the curvature of the slow curve, resulting in a better suppression effect on the transverse mode of the formed surface acoustic wave device 00. Figure 11 This is a graph showing the change in curvature of the horizontal shear wave slowness curve of a surface acoustic wave device as a function of a first ratio, according to an embodiment of the present invention. Figure 11 The horizontal axis represents the first ratio G / W, and the vertical axis represents the curvature γ of the slow curve. Figure 11 It can be further clarified that when G / W ≥ 0.125, the curvature γ of the slowness curve is less than 0 and the value gradually decreases. Therefore, when G / W ≥ 0.125, the formed surface acoustic wave device 00 does not have a transverse mode, which is beneficial to improving the overall performance of the surface acoustic wave device 00.

[0036] Based on the above embodiments, Figure 12 yes Figure 8 A schematic diagram of the cross-sectional structure along the C-C' direction. (See also...) Figure 12 Optionally, the piezoelectric substrate 100 includes a substrate 101, a trapping material layer 102, a low sound velocity layer 103 and a piezoelectric thin film layer 104 stacked together. The electrode layer 200 is disposed on the surface of the piezoelectric thin film layer 104 away from the substrate 101.

[0037] Specifically, the substrate 101 can be made of silicon material, which supports the other film layers and the electrode layer 200. The trapping material layer 102 can be made of polycrystalline silicon material, the low sound velocity layer 103 can be made of silicon dioxide material, and the piezoelectric thin film layer 104 can be made of materials such as piezoelectric ceramics with piezoelectric effect.

[0038] Based on the above embodiments, see below. Figure 8 and Figure 12 Optionally, in the thickness direction of the piezoelectric substrate 100, each electrode finger in the electrode layer 200 has a preset thickness h; The preset thickness h has a second ratio to the wavelength λ of the surface acoustic wave, and the second width W has a third ratio to the first width G; The second ratio is greater than or equal to 6% of the third ratio, and the second ratio is less than or equal to 12% of the third ratio.

[0039] Specifically, the direction perpendicular to both the first direction X and the second direction Y can be defined as the height direction of the surface acoustic wave device 00, i.e., the thickness direction of the piezoelectric substrate 100. In the thickness direction, the electrode layer 200 has a preset thickness h, i.e., each electrode finger in the interdigital transducer electrode 202 has a preset thickness h. The distance between two adjacent electrode fingers on the same side is the wavelength λ of the surface acoustic wave. The second ratio h / λ is obtained by dividing the preset thickness h by the wavelength λ of the surface acoustic wave; the third ratio W / G is obtained by dividing the second width W by the first width G. By setting 6%×W / G≤h / λ≤12%×W / G, the surface acoustic wave device 00 formed can be guaranteed to have the function of propagating acoustic wave signals. Preferably, the preset thickness h of the electrode fingers and the first width G of the hollow structure 203 on the electrode fingers are set to the following quantitative relationship: h=10%×W / G. Figure 13 This is a comparative curve showing the change in the curvature of the slowness curve of a surface acoustic wave device provided in an embodiment of the present invention as a function of a second ratio. (See also...) Figure 13 This is a dotted curve graph, with the horizontal axis representing the second ratio h / λ and the vertical axis representing the curvature γ of the slow curve. Specifically, the black square dotted curve 17 represents the slow curve curvature change curve of the surface acoustic wave device with a hollow structure on the electrode finger provided in this embodiment of the invention, and the red dotted curve 18 represents the slow curve curvature change curve of the surface acoustic wave device with a complete strip of metal electrode finger provided in related technologies. Figure 13 It can be seen that the curvature γ of the slow curve corresponding to the black square dot curve 17 is smaller than that of the slow curve corresponding to the red dot curve 18, and the curvature γ of the slow curve corresponding to the black square dot curve 17 is generally less than 0, while the curvature γ of the slow curve corresponding to the red dot curve 18 is generally greater than 0. Furthermore, when the second ratio h / λ is greater than 5%, the curvature γ of the slow curve corresponding to the black square dot curve 17 gradually decreases as the second ratio h / λ increases. Thus, it can be concluded that when the second ratio h / λ is greater than 5%, the surface acoustic wave device provided in this embodiment of the invention has a better suppression effect on the transverse mode.

[0040] Based on the above embodiments, Figure 14 This is a top view schematic diagram of another surface acoustic wave device provided in an embodiment of the present invention. Figure 15 This is a top view schematic diagram of another surface acoustic wave device provided in an embodiment of the present invention. See also Figure 8 , Figure 9 , Figure 14 and Figure 15 Optionally, the orthographic projection shape of the hollow structure 203 on the surface of the piezoelectric substrate 100 includes any one of rectangle, circle and triangle.

[0041] Specifically, in the interdigital transducer electrodes 202, the shape of the hollow structure 203 provided on each electrode finger, projected onto the piezoelectric substrate 100, can be rectangular, circular, or triangular, without limitation. Furthermore, regardless of the shape of the hollow structure 203, as long as the ratio of the first width G of the hollow structure 203 to the second width W of the electrode finger is within the range of [0.125, 1), the transverse mode of the surface acoustic wave device 00 can be effectively suppressed, improving the overall performance of the device.

[0042] Based on the above embodiments, see below. Figure 8 Optionally, in the first direction X, reflectors are respectively provided on both sides of the interdigital transducer electrode 202; The reflector includes a reflector busbar and multiple reflector electrodes, the reflector electrodes extending along the second direction Y, and the multiple reflector electrodes arranged in parallel along the first direction X; In the second direction Y, a reflector busbar is provided at each end of the reflector electrode, and both ends of the reflector electrode are electrically connected to the reflector busbar.

[0043] Specifically, by setting up a reflector with multiple reflector electrodes arranged in parallel in the first direction X, and both ends of the reflector electrodes being electrically connected to the reflector busbar, and by setting the reflectors at both ends of the interdigital transducer electrode 202 and the busbar 201 in the first direction X, surface acoustic waves can be reflected, focused, and frequency-selected, thereby forming a resonance or filtering effect. This is beneficial for suppressing stray modes, confining acoustic wave energy, and reducing losses. It should be noted that the reflector, reflector electrodes, and reflector busbar structure in the surface acoustic wave device provided in this embodiment of the invention are the same as the reflector structure and arrangement in related technologies, and therefore are not shown again in the accompanying drawings.

[0044] This invention also provides a filter device. Figure 16 This is a schematic diagram of a filter device provided in an embodiment of the present invention. See also... Figure 16 The filter device 300 includes: Series arm resonator 3001; and, Parallel arm resonator 3002; Among them, at least one of the series arm resonator 3001 and the parallel arm resonator 3002 is a surface acoustic wave device 00 as provided in any of the above embodiments.

[0045] Specifically, the series arm resonator 3001 is connected in series between the input terminal 3003 and the output terminal 3004, and one end of the parallel arm resonator 3002 is connected between the input terminal 3003 and the output terminal 3004, while the other end is grounded. At least one of the series arm resonator 3001 and the parallel arm resonator 3002 in the filter device provided in this embodiment of the invention employs the surface acoustic wave device 00 provided in any of the above embodiments, and possesses similar beneficial effects to the surface acoustic wave device 00 provided in any of the above embodiments, which will not be elaborated upon here.

[0046] This invention also provides a multiplexer. Figure 17 This is a schematic diagram of a filter device provided in an embodiment of the present invention. See also... Figure 17 The multiplexer 400 includes: The antenna terminal ANT is electrically connected to the antenna; and, Multiple filter units 4001 are all communicatively connected to the antenna terminal ANT; At least one filtering unit 4001 is a filter device 300 as provided in the above embodiments.

[0047] At least one filtering unit 4001 in the multiplexer provided in this embodiment of the invention is the filter device 300 provided in the above embodiment, and has similar beneficial effects as the filter device 300 provided in the above embodiment, which will not be described in detail here.

[0048] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A surface acoustic wave device, characterized in that, include: piezoelectric substrate; An electrode layer is disposed on the surface of the piezoelectric substrate; the electrode layer includes a busbar and interdigitated transducer electrodes; the interdigitated transducer electrodes include a plurality of electrode fingers arranged parallel and staggered in a first direction, and the electrode fingers extend along a second direction; the busbar is disposed parallel to both ends of the interdigitated transducer electrodes in the second direction, and the busbar is connected to the adjacent electrode fingers; the second direction intersects the first direction; Each of the electrode fingers is provided with at least two hollow structures, and in the second direction, the at least two hollow structures are arranged at periodic intervals.

2. The surface acoustic wave device according to claim 1, characterized in that, Each of the electrode fingers is provided with at least two rows of gaps, and each row of gaps is provided with at least two hollow structures; At least two of the gap columns are arranged parallel and spaced apart in a direction perpendicular to the second direction, and a plurality of the hollow structures in the gap columns are arranged in an array.

3. The surface acoustic wave device according to claim 2, characterized in that, The hollow structure has a first width in the direction perpendicular to the second direction, and the electrode finger has a second width; wherein the first width is the sum of the widths of the hollow structures in the electrode finger in the direction perpendicular to the second direction; The first width and the second width have a first ratio; the first ratio is greater than or equal to 0.125 and less than 1.

4. The surface acoustic wave device according to claim 3, characterized in that, In the thickness direction of the piezoelectric substrate, each of the electrode fingers in the electrode layer has a predetermined thickness; The preset thickness has a second ratio to the wavelength of the surface acoustic wave, and the second width has a third ratio to the first width; The second ratio is greater than or equal to 6% of the third ratio, and the second ratio is less than or equal to 12% of the third ratio.

5. The surface acoustic wave device according to claim 2, characterized in that, The orthographic projection shape of the hollow structure on the surface of the piezoelectric substrate includes any one of rectangle, circle and triangle.

6. The surface acoustic wave device according to claim 1, characterized in that, The interdigital transducer electrode includes a first electrode group and a second electrode group. The first electrode group includes a plurality of first electrode fingers arranged in parallel, and the second electrode group includes a plurality of second electrode fingers arranged in parallel. The plurality of first electrode fingers and the plurality of second electrode fingers are arranged in an interlaced manner. The busbar includes a first busbar and a second busbar, and a plurality of first electrode fingers are electrically connected to the first busbar, and a plurality of second electrode fingers are electrically connected to the second busbar.

7. The surface acoustic wave device according to claim 1, characterized in that, In the first direction, reflectors are respectively provided on both sides of the interdigital transducer electrode; The reflector includes a reflector busbar and a plurality of reflector electrodes, the reflector electrodes extending along the second direction, and the plurality of reflector electrodes being arranged in parallel in the first direction; In the second direction, a reflector busbar is provided at each end of the reflector electrode, and both ends of the reflector electrode are electrically connected to the reflector busbar.

8. The surface acoustic wave device according to claim 1, characterized in that, The piezoelectric substrate includes a substrate, a trapping material layer, a low-velocity layer and a piezoelectric thin film layer stacked together. The electrode layer is disposed on the surface of the piezoelectric thin film layer away from the substrate.

9. A filter device, characterized in that, include: Series arm resonator; as well as, Parallel arm resonator; Wherein, at least one of the series arm resonator and the parallel arm resonator is a surface acoustic wave device as described in any one of claims 1 to 8.

10. A multiplexer, characterized in that, include: Antenna terminal, electrically connected to the antenna; as well as, Multiple filtering units are all communicatively connected to the antenna terminal; Wherein, at least one of the filtering units is the filter device as described in claim 9.

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