Surface acoustic wave devices, filters and RF front-end modules

Abstract

The present application provides a surface acoustic wave device, a filter and a radio frequency front-end module. The surface acoustic wave device includes a piezoelectric substrate and an interdigital transducer. The interdigital transducer includes an electrode unit and two bus bars arranged at intervals along a first direction; the electrode unit includes a first connecting bar and two resonance units, the two resonance units are arranged along the first direction, and the two resonance units are connected by the same connection mechanism; the resonance unit includes a first conductive strip, a first finger bar portion, a second finger bar portion and a second conductive strip; the bus bar is connected to the first conductive strip through a first connecting bar, the first conductive strip is connected to the first finger bar portion, and the second finger bar portion is connected to the second conductive strip; the first connecting bar and the first conductive strip are arranged in a non-crossing area; in the same electrode unit, the number of first connecting bars connected to the resonance unit is less than the number of first finger bar portions. The surface acoustic wave device, filter and radio frequency front-end module can take into account both reducing the influence of heterogeneous modes and miniaturizing the size of the device.

Description

Technical Field

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

[0002] Surface acoustic wave devices utilize the characteristics of acoustic-electric transducers to process acoustic signals propagating on the surface of materials with piezoelectric properties. Surface acoustic wave devices have the advantages of low cost, small size and multiple functions, and therefore have been widely used in radar, communication, navigation, identification and other fields. Surface acoustic wave devices include interdigital transducers (IDTs), which can convert electrical signals into acoustic signals or convert acoustic signals into electrical signals. When the surface acoustic wave device is working, in addition to the lateral strays generated by the acoustic waves in the aperture direction, there are also stray modes in the gap area formed between the busbar and the multiple electrode fingers, referred to as stray modes. The existence of stray modes will have a significant impact on the performance of the surface acoustic wave device. However, it is difficult for surface acoustic wave devices in related technologies to achieve miniaturization of the device size while reducing stray modes. Utility Model Content

[0003] The present application provides a surface acoustic wave device, a filter and a radio frequency front-end module, aiming to achieve both reducing the influence of stray modes and miniaturizing the size of the device.

[0004] The present application provides a surface acoustic wave device, the surface acoustic wave device comprising a piezoelectric substrate and an interdigital transducer, the interdigital transducer is arranged on the piezoelectric substrate, the interdigital transducer comprises an electrode unit and two bus bars, the two bus bars are arranged at intervals along a first direction; the electrode unit comprises:

[0005] first connecting strip;

[0006] Two resonance units, the two resonance units are arranged along the first direction, and the two resonance units are connected by the same connection mechanism; the resonance unit includes a first conductive strip, a first finger portion, a second finger portion and a second conductive strip; the bus bar is connected to the first conductive strip through the first connecting strip, the first conductive strip is connected to the first finger portion, the second finger portion is connected to the second conductive strip, and the first finger portion and the second finger portion are arranged at intervals along a second direction perpendicular to the first direction; in the first direction, there are crossing areas and non-crossing areas between the two bus bars, and the first connecting strip and the first conductive strip are arranged in the non-crossing area; in the second direction, the crossing area is an area where the first finger portion and the second finger portion overlap each other; wherein, in the same electrode unit, the number of the first connecting strips connected to the resonance unit is less than the number of the first finger portions of the resonance unit.

[0007] In the surface acoustic wave device according to the embodiment of the present application, the frequencies of the two resonant units are the same.

[0008] In the surface acoustic wave device according to the embodiment of the present application, the second conductive strips of the two resonant units are arranged at intervals along the first direction; the connection mechanism includes:

[0009] A second connection strip, both ends of the second connection strip are respectively connected to the two second conductive strips, and the number of the second connection strips is less than the number of the second finger portions connected by the second conductive strips.

[0010] In the surface acoustic wave device according to the embodiment of the present application, the non-crossing region includes a first intermediate gap region, the first intermediate gap region is the region between the two second conductive strips, and the dimension of the first intermediate gap region along the first direction is F1, 0.5λ < F1 < 2λ, where λ is the wavelength of the surface acoustic wave device.

[0011] In the surface acoustic wave device according to the embodiment of the present application, the dimension of the second conductive strip along the first direction is W1, 0.1λ < W1 < 0.3λ, where λ is the wavelength of the surface acoustic wave device.

[0012] In the surface acoustic wave device according to the embodiment of the present application, the metallization rate of the first finger portion and / or the second finger portion is ε1, and the metallization rate of the first connection strip and / or the second connection strip is ε2, 0.95ε1 < ε2 < 1.05ε1; and / or, the metallization rate of the first connection strip and / or the second connection strip is ε2, 0.15 < ε2 < 0.75.

[0013] In the surface acoustic wave device according to the embodiment of the present application, the two resonant units share one second conductive strip, and the connection mechanism includes the second conductive strip.

[0014] In the surface acoustic wave device according to the embodiment of the present application, the non-crossing region includes a second intermediate gap region, the second intermediate gap region is the region between the crossing region and the second conductive strip, and the dimension of the second intermediate gap region along the first direction is F2, 0.05λ < F2 < 0.5λ, where λ is the wavelength of the surface acoustic wave device.

[0015] In the surface acoustic wave device according to the embodiment of the present application, the dimension of the second conductive strip along the first direction is W2, 0.2λ < W2 < 0.8λ, where λ is the wavelength of the surface acoustic wave device.

[0016] In the surface acoustic wave device according to the embodiment of the present application, the non-crossing region includes a second intermediate gap region, the second intermediate gap region is the region between the crossing region and the second conductive strip, the metallization rate of the first finger portion and / or the second finger portion is ε1, the metallization rate of the second intermediate gap region is ε3, and 0.8ε1 < ε3 < 1.2ε1.

[0017] In the surface acoustic wave device according to the embodiment of the present application, the size of the first conductive strip along the first direction is W3, and 0.1λ < W3 < 0.3λ, where λ is the wavelength of the surface acoustic wave device.

[0018] In the surface acoustic wave device according to the embodiment of the present application, the size of the first connection strip along the first direction is L1, and 0.3λ < L1 < 2.5λ, where λ is the wavelength of the surface acoustic wave device.

[0019] In the surface acoustic wave device according to the embodiment of the present application, the surface acoustic wave device has at least one of the following features:

[0020] The axes of the first finger portions of one of the resonant units and the first finger portions of another resonant unit coincide along the first direction; and / or,

[0021] The axes of the second finger portions of one of the resonant units and the second finger portions of another resonant unit coincide along the first direction; and / or,

[0022] In the same resonant unit, the axis of the first connection strip along the first direction coincides with the axis of one of the second finger portions along the first direction.

[0023] In the surface acoustic wave device according to the embodiment of the present application, the two resonant units are axisymmetric with respect to the connection mechanism.

[0024] The embodiment of the present application further provides a filter, including the surface acoustic wave device according to any one of the above.

[0025] The embodiment of the present application further provides a radio frequency front-end module, including the surface acoustic wave device according to any one of the above.

[0026] The surface acoustic wave device, filter and RF front-end module provided in the embodiment of the present application can change the original periodicity of the finger-bar portion by connecting at least two first finger-bar portions through a first conductive strip, thereby weakening the stray mode; and by making the number of the first connecting strips in the same electrode unit smaller than the number of the first finger-bar portions, that is, the at least two first finger-bar portions connected together are connected to the bus bar through less than the number of first connecting strips, it is possible to reduce the possibility of generating an equivalent resonant cavity in the non-intersection area, thereby reducing the possibility of oscillation of the stray mode, avoiding the excitation of the acoustic wave energy leaked from the intersection area to the non-intersection area, and then achieving the suppression of the stray mode, thereby reducing or avoiding the stray mode affecting the performance of the surface acoustic wave device. In addition, since the two resonant units are arranged along the first direction and the two resonant units are connected by the same connecting mechanism, the two resonant units can be cascaded through the connecting mechanism without the need for cascading through external wiring, which is beneficial to reducing the layout area of ​​the surface acoustic wave device, and thus is beneficial to miniaturizing the size of the device, and the structural design of the surface acoustic wave device is reasonable and compact.

[0027] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and cannot limit the disclosure of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 It is a schematic diagram of the structure of a surface acoustic wave device in the related art;

[0030] Figure 2 is a schematic structural diagram of a surface acoustic wave device provided in one embodiment of the present application;

[0031] Figure 3 is a schematic structural diagram of a surface acoustic wave device provided in one embodiment of the present application;

[0032] Figure 4 is a schematic structural diagram of a surface acoustic wave device provided in one embodiment of the present application;

[0033] Figure 5 It is a comparison diagram of the admittance curves of the surface acoustic wave device of the related art and an embodiment of the present application.

[0034] Description of reference numerals:

[0035] 1000. Surface acoustic wave devices;

[0036] 100. Interdigital transducer;

[0037] 10. bus bar; 11. first bus bar; 12. second bus bar;

[0038] 20, electrode unit; 21, first connecting strip; 22, resonance unit; 22a, first resonance unit; 22b, second resonance unit; 221, first conductive strip; 222, first finger strip portion; 223, second finger strip portion; 224, second conductive strip;

[0039] 30. Connecting mechanism; 31. Second connecting strip; 40. Low sound velocity portion;

[0040] A0, intersection area; A1, middle area; A2, edge area; B1, middle gap area; B2, edge non-intersection area; B21, first gap area; B22, second gap area;

[0041] 200. Reflective structure. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0044] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0045] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0046] See also Figure 1 , a surface acoustic wave device 1000 in the related art includes a piezoelectric substrate (not shown) and an interdigital transducer 100, and the interdigital transducer 100 is arranged on the piezoelectric substrate. The interdigital transducer 100 cooperates with the piezoelectric substrate to convert an electrical signal into an acoustic wave or convert an acoustic wave into an electrical signal. The surface acoustic wave device 1000 may also include a reflection structure 200, and the reflection structure 200 may be arranged on two opposite sides of the interdigital transducer 100. Specifically, in the direction of acoustic wave propagation, the reflection structure 200 is arranged on two opposite sides of the interdigital transducer 100; the reflection structure 200 is used to reflect the acoustic wave and confine the acoustic wave to the area where the interdigital transducer 100 is located.

[0047] In conjunction with the accompanying drawings of the present application, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0048] In some embodiments of the present application, the surface acoustic wave device 1000 may include a surface acoustic wave resonator. The surface acoustic wave resonator may be a normal surface acoustic wave resonator (Normal-SAW), a temperature compensated surface acoustic wave resonator (TC-SAW), a surface acoustic wave resonator with a multi-layer substrate structure, or a transversely excited thin film bulk acoustic wave resonator, etc.

[0049] In some embodiments, the material of the piezoelectric substrate may specifically include at least one of quartz, aluminum nitride, sapphire, LN (lithium niobate, Li NbO 3 ), LT (lithium tantalate, Li TaO 3 ), etc., which is not specifically limited in this embodiment.

[0050] See also Figure 2 In some embodiments, the piezoelectric substrate includes a stacked piezoelectric film (not shown) and a substrate (not shown), and the interdigital transducer 100 is disposed on the surface of the piezoelectric film away from the substrate. In this way, the Q value of the surface acoustic wave device 1000 can be improved and can be applied to higher frequency bands of 5G and above. Exemplarily, the material of the substrate can be silicon.

[0051] In some embodiments, the material of the IDT 100 can be a single metal material or a composite or alloy material of different metals. Optionally, the material of the IDT 100 can be aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, etc. or a composite of the above metals or one of their alloys.

[0052] See also Figure 2 In some embodiments, the IDT 100 includes an electrode unit 20 and two bus bars 10, the two bus bars 10 are arranged at intervals along a first direction; the electrode unit 20 includes a first connecting bar 21 and two resonance units 22, the two resonance units 22 are arranged along the first direction, and the two resonance units 22 are connected by the same connection mechanism 30; the resonance unit 22 includes a first conductive strip 221, a first finger strip portion 222, a second finger strip portion 223, and a second conductive strip 224; the bus bar 10 is connected to the first conductive strip 221 through the first connecting bar 21, and the first conductive strip 221 is connected to the first finger strip portion 222. The second finger portion 223 is connected to the second conductive strip 224, and the first finger portion 222 and the second finger portion 223 are arranged at intervals along a second direction perpendicular to the first direction; in the first direction, there are an intersection area A0 and a non-intersection area between the two bus bars 10, and the first connecting bar 21 and the first conductive strip 221 are arranged in the non-intersection area; in the second direction, the intersection area A0 is the area where the first finger portion 222 and the second finger portion 223 overlap with each other; wherein, in the same electrode unit 20, the number of first connecting bars 21 connected to the resonance unit 22 is less than the number of first finger portions 222 of the resonance unit 22.

[0053] The surface acoustic wave device 1000 of the above-mentioned embodiment connects at least two first finger portions 222 through the first conductive strip 221, which can change the original periodicity of the finger portion, thereby weakening the stray mode; and by the number of first connecting strips 21 connected to the resonance unit 22 in the same electrode unit 20 being less than the number of first finger portions 222 of the resonance unit 22, that is, at least two first finger portions 222 connected together are connected to the bus bar 10 through first connecting strips 21 less than this number, it is possible to reduce the possibility of generating an equivalent resonant cavity in the non-intersection area, thereby reducing the possibility of oscillation of the stray mode, avoiding the excitation of the sound wave energy leaking from the intersection area A0 to the non-intersection area, and then achieving the suppression of the stray mode, thereby reducing or avoiding the stray mode affecting the performance of the surface acoustic wave device 1000. In addition, since the two resonant units 22 are arranged along the first direction and connected by the same connecting mechanism 30, the two resonant units 22 can be cascaded by the connecting mechanism 30 without the need for cascading through external wiring, which is beneficial to reducing the layout area of ​​the surface acoustic wave device 1000, and further beneficial to miniaturizing the size of the device. The structure design of the surface acoustic wave device 1000 is reasonable and compact. The surface acoustic wave device 1000 of the embodiment of the present application can take into account both the miniaturization of the device size and the reduction of the influence of the stray mode on the performance of the surface acoustic wave device 1000; the two resonant units 22 are connected by the same connecting mechanism 30, which can reduce the size of the surface acoustic wave device 1000 without weakening the stray mode suppression effect of the resonant unit 22.

[0054] See also Figure 2 In the first direction, the intersection area A0 includes a middle area A1 and edge areas A2 located on both sides of the middle area A1. The non-intersection area is the area between the two bus bars 10 except the intersection area A0. Figure 2 In some embodiments, in the first direction, the non-intersection area includes a middle gap area B1 and an edge non-intersection area B2, the middle gap area B1 is located between the two resonant units 22, and the edge non-intersection area B2 is located on the side of the intersection area A0 away from the middle gap area B1. In the same middle gap area B1, in the first direction, the middle gap area B1 includes a first gap area B21 and a second gap area B22, the first gap area B21 is the area between the bus bar 10 and the first conductive strip 221, and the second gap area B22 is the area between the intersection area A0 and the first conductive strip 221. For example, please refer to Figure 2 , the number of intersection areas A0 is two, the number of edge non-intersection areas B2 includes two, one edge non-intersection area B2, one intersection area A0, the middle gap area B1, another intersection area A0 and another edge non-intersection area B2 are arranged in sequence along the first direction. The number of the middle gap area B1 can be set according to actual needs, for example Figure 2 The one shown, and Figure 3 2 shown.

[0055] See also Figure 2 , exemplarily, the two bus bars 10 are respectively the first bus bar 11 and the second bus bar 12, and the first bus bar 11 and the second bus bar 12 are arranged on the piezoelectric substrate at intervals along the first direction. The two resonant units 22 are respectively the first resonant unit 22a and the second resonant unit 22b, the first connecting bar 21 connecting the first resonant unit 22a and the first bus bar 11 is recorded as the connecting bar 21a, and the two ends of the connecting bar 21a are respectively connected to the first bus bar 11 and the first conductive bar 221 of the first resonant unit 22a; the first connecting bar 21 connecting the second resonant unit 22b and the second bus bar 12 is recorded as the connecting bar 21b, and the two ends of the connecting bar 21b are respectively connected to the second bus bar 12 and the first conductive bar 221 of the second resonant unit 22b. In the first resonant unit 22a, the first conductive bar 221 is connected to the first finger bar portion 222, the second finger bar portion 223 is connected to the second conductive bar 224, and the first finger bar portion 222 and the second finger bar portion 223 are arranged at intervals along the second direction. In the second resonance unit 22b, the first conductive strip 221 is connected to the first finger strip portion 222, the second finger strip portion 223 is connected to the second conductive strip 224, and the first finger strip portion 222 and the second finger strip portion 223 are arranged at intervals along the second direction. Exemplarily, the number of the connecting strips 21a is less than the number of the first finger strip portions 222 of the first resonance unit 22a, and the number of the connecting strips 21b is less than the number of the first finger strip portions 222 of the second resonance unit 22b.

[0056] Exemplarily, the first direction is perpendicular to the second direction, which means that the first direction is perpendicular to the second direction on the plane where the piezoelectric substrate is located. Exemplarily, the first direction is the arrangement direction of the two bus bars 10 or the length extension direction of the finger bar portions, and the second direction is the sound wave propagation direction or the arrangement direction of each finger bar portion. Exemplarily, the first direction is as follows: Figure 2 The X direction is shown in the second direction. Figure 2 As shown in the Y direction.

[0057] In some embodiments, in the same electrode unit 20, the ratio of the number of the first finger portions 222 of the resonance unit 22 to the number of the first connecting bars 21 connected to the resonance unit 22 is A, and A is greater than 1 and less than or equal to 8, such as A is 2, 3, 4, 5, 6, 7, 8 or any other suitable value between 1 and 8. If A is too small, the current in the area where the first connecting bar 21 is located (i.e., the first gap area B21) will be too large, and the surface acoustic wave device 1000 will be easily burned; if A is too large, the routing of the first connecting bar 21 will be too long, and the surface acoustic wave device 1000 will be easily burned. A being within this range can effectively reduce the possibility of generating an equivalent resonant cavity in the edge non-intersection area B2, thereby effectively reducing the possibility of oscillation of the stray mode, and avoiding as much as possible the excitation of the acoustic wave energy leaking from the intersection area A0 to the edge non-intersection area B2, thereby effectively achieving the suppression of the stray mode; in addition, A being within this range can effectively reduce the mass of the first connecting strip 21, and make the first connecting strip 21 and each first finger strip portion 222 have a suitable equivalent resistance, so that the surface acoustic wave device 1000 is more reliable and the surface acoustic wave device 1000 is not easy to burn. Exemplarily, the ratio of the number of the first finger strip portions 222 of the resonance unit 22a to the number of the connection strips 21a is A; the ratio of the number of the first finger strip portions 222 of the resonance unit 22b to the number of the connection strips 21b is A.

[0058] Exemplarily, the number of first connecting strips 21 connected to the resonance unit 22 is one, such as the number of connecting strips 21a or 21b is one. In this way, the possibility of generating an equivalent resonant cavity in the edge non-intersection area B2 can be reduced as much as possible, thereby reducing the possibility of oscillation of the stray mode as much as possible, and avoiding the excitation of the acoustic wave energy leaking from the intersection area A0 to the edge non-intersection area B2 to the greatest extent, thereby achieving the maximum suppression of the stray mode; in addition, the mass of the first connecting strip 21 can be reduced as much as possible, and the first connecting strip 21 and each first finger strip portion 222 have a suitable equivalent resistance, so that the surface acoustic wave device 1000 is more reliable and less likely to burn.

[0059] In some embodiments, the frequencies of the two resonance units 22 are the same. Since the frequencies of the two resonance units 22 are the same, the series resonance formed by the two resonance units 22 in series makes the size of the surface acoustic wave device 1000 along the first direction longer; when the admittance remains basically unchanged, the size of the surface acoustic wave device 1000 along the first direction becomes longer, and the field strength inside the surface acoustic wave device 1000 is greatly reduced, which helps to improve the nonlinear effect, and can suppress some harmonic signals (especially high-order harmonic signals, hereinafter referred to as "high-order harmonics"), reduce the interference of high-order harmonics on the fundamental signal, and ensure the signal transmission quality of the surface acoustic wave device 1000. It can be understood that the frequency of the high-order harmonics is N times the signal frequency of the fundamental wave, and N is greater than 1. For example, when the high-order harmonics are second harmonics, the frequency of the high-order harmonics is twice the signal frequency of the fundamental wave.

[0060] See also Figure 2 In some embodiments, the second conductive strips 224 of the two resonant units 22 are arranged at intervals along the first direction; the connecting mechanism 30 includes a second connecting strip 31, and the two ends of the second connecting strip 31 are respectively connected to the two second conductive strips 224, and the number of the second connecting strips 31 is less than the number of the second finger strip portions 223 connected to the second conductive strip 224. Since the number of the second connecting strips 31 is less than the number of the second finger strip portions 223 of the resonant unit 22, that is, at least two second finger strip portions 223 connected together in one resonant unit 22 are connected to another resonant unit 22 through the second connecting strips 31 less than the number, it is possible to reduce the generation of an equivalent resonant cavity in the middle gap area B1 or the area between the two resonant units 22, and further reduce the possibility of generating an equivalent resonant cavity in the middle gap area B1 or the area between the two resonant units 22, thereby further reducing the possibility of oscillation of the stray mode, avoiding the excitation of the acoustic wave energy leaked from the cross area A0 to the middle gap area B1 or the area between the two resonant units 22, and further achieving the suppression of the stray mode, thereby further avoiding the stray mode from affecting the performance of the surface acoustic wave device 1000.

[0061] In some embodiments, the ratio of the number of the first finger portions 222 of the resonant unit 22 to the number of the second connection bars 31 connected to the resonant unit 22 is B, where B is greater than 1 and less than or equal to 8. For example, B is 2, 3, 4, 5, 6, 7, 8 or any other suitable value between 1 and 8. If B is too small, the current in the region where the second connection bar 31 is located will be too large, and the surface acoustic wave device 1000 is likely to be burned out. If B is too large, the trace of the second connection bar 31 will be too long, and the surface acoustic wave device 1000 is likely to be burned out. When B is within this range, it can effectively reduce the possibility of generating an equivalent resonant cavity in the middle gap region B1, thereby effectively reducing the possibility of the parasitic mode starting oscillation, and尽可能 avoiding the acoustic wave energy leaked from the crossover region A0 to the middle gap region B1 from being excited, and further effectively achieving the suppression of the parasitic mode. In addition, when B is within this range, it can effectively reduce the mass of the second connection bar 31 and make the second connection bar 31 and each second finger portion 223 have a suitable equivalent resistance, making the surface acoustic wave device 1000 more reliable and less likely to be burned out.

[0062] Exemplarily, the number of the second connection bars 31 is one. In this way, it can尽可能 reduce the possibility of generating an equivalent resonant cavity in the middle gap region B1, thereby尽可能 reducing the possibility of the parasitic mode starting oscillation, and最大程度 avoiding the acoustic wave energy leaked from the crossover region A0 to the middle gap region B1 from being excited, and further最大程度 achieving the suppression of the parasitic mode. In addition, it can also尽可能 reduce the mass of the second connection bar 31 and make the second connection bar 31 and each second finger portion 223 have a suitable equivalent resistance, making the surface acoustic wave device 1000 more reliable and less likely to be burned out.

[0063] In some embodiments, the non-crossover region includes a first middle gap region, and the first middle gap region is the region between two second conductive bars 224. The size of the first middle gap region in the first direction is F1, where 0.5λ < F1 < 2λ, and λ is the wavelength of the surface acoustic wave device 1000. In this way, it is beneficial to reduce the mass of the surface acoustic wave device 1000 and can further effectively suppress the parasitic mode on the high-frequency side of the anti-resonant point, improving the parasitic mode suppression effect. Exemplarily, the first middle gap region is as shown in the middle gap region B1 in Figure 2 That is, in the embodiment shown in Figure 2 the size of the middle gap region B1 in the first direction is greater than 0.5λ and less than 2λ.

[0064] Please refer to Figure 2, in some embodiments, the size of the second conductive strip 224 in the first direction is W1, where 0.1λ < W1 < 0.3λ, and λ is the wavelength of the surface acoustic wave device 1000. If W1 is too small, it is easy to cause the trace to burn out. If W1 is too large, the suppression effect of the spurious mode on the high-frequency side of the anti-resonant point will be reduced. When 0.1λ < W1 < 0.3λ, it can take into account better spurious mode suppression effect and reliability. The spurious mode suppression effect on the high-frequency side of the anti-resonant point is good, and it is not easy to cause the trace to burn out. In addition, it can also make the processing of the surface acoustic wave device 1000 easier. Exemplarily, the size of the second conductive strip 224 in the first direction is the same as the size of the first conductive strip 221 in the first direction, so as to ensure that the surface acoustic wave device 1000 can form an overall symmetric electric field, and further effectively ensure that the surface acoustic wave device 1000 has a good excitation effect and improve the performance of the surface acoustic wave device 1000. Of course, in other embodiments, the size of the second conductive strip 224 in the first direction may also be different from the size of the first conductive strip 221 in the first direction.

[0065] In some embodiments, the metallization rate of the first finger portion 222 and / or the second finger portion 223 is ε1, and the metallization rate of the first connection strip 21 and / or the second connection strip 31 is ε2, where 0.95ε1 < ε2 < 1.05ε1; and / or, the metallization rate of the first connection strip 21 and / or the second connection strip 31 is ε2, where 0.15 < ε2 < 0.75. If ε1 and / or ε2 is too small, the resistance of the surface acoustic wave device 1000 is large, resulting in the surface acoustic wave device 1000 being easily burned out. In addition, if ε1 and / or ε2 is too small, it will also make the processing of the surface acoustic wave device 1000 difficult and not easy to process. Moreover, if ε1 and / or ε2 is too large, the positive and negative electrodes of the surface acoustic wave device 1000 are too close and easy to break down; it will also cause the sound velocity to decrease and the energy suppression effect to weaken. When 0.95ε1 < ε2 < 1.05ε1, the surface acoustic wave device 1000 has high reliability and is not easy to burn out, and the surface acoustic wave device 1000 is not easy to break down due to the too-close distance between its positive and negative electrodes; and it is easy to process, has a relatively high sound velocity, and has a good energy suppression effect. Similarly, when 0.15 < ε2 < 0.75, the surface acoustic wave device 1000 has high reliability and is not easy to burn out, and the surface acoustic wave device 1000 is not easy to break down due to the too-close distance between its positive and negative electrodes; and it is easy to process, has a relatively high sound velocity, and has a good energy suppression effect.

[0066] Please refer to Figure 3 , in some embodiments, two resonant units 22 share a second conductive strip 224, and the connection mechanism 30 includes the second conductive strip 224. In this way, the structure of the surface acoustic wave device 1000 is compact, which can effectively reduce the mass and volume of the surface acoustic wave device 1000, and can further effectively suppress the spurious mode on the high-frequency side of the anti-resonant point and improve the spurious mode suppression effect.

[0067] In some embodiments, the non-crossing region includes a second intermediate gap region, which is the region between the crossing region A0 and the second conductive strip 224. The dimension of the second intermediate gap region in the first direction is F2, where 0.05λ < F2 < 0.5λ and λ is the wavelength of the surface acoustic wave device 1000. The range of 0.05λ < F2 < 0.5λ can balance reliability and a good spurious mode suppression effect. The spurious mode suppression effect on the high-frequency side of the anti-resonant point is good, and it is not easy to cause the trace to burn out. In addition, it can also make the processing of the surface acoustic wave device 1000 easier. Exemplarily, the second intermediate gap region is as shown in Figure 3 the intermediate gap region B1 in Figure 3 That is, in the embodiment shown in

[0068] Please refer to Figure 3 , in some embodiments, the dimension of the second conductive strip 224 in the first direction is W2, where 0.2λ < W2 < 0.8λ and λ is the wavelength of the surface acoustic wave device 1000. If W2 is too small, it is easy to cause the trace to burn out. If W2 is too large, the spurious mode suppression effect on the high-frequency side of the anti-resonant point will be reduced. The range of 0.2λ < W2 < 0.8λ can balance a good spurious mode suppression effect and reliability. The spurious mode suppression effect on the high-frequency side of the anti-resonant point is good, and it is not easy to cause the trace to burn out. In addition, it can also make the processing of the surface acoustic wave device 1000 easier. In this embodiment, the dimension of the second conductive strip 224 in the first direction and the dimension of the first conductive strip 221 in the first direction can be the same or different. Even if the dimension of the second conductive strip 224 in the first direction and the dimension of the first conductive strip 221 in the first direction are different, as long as the electrode unit 20 is axisymmetric about the shared second conductive strip 224, it can ensure that the surface acoustic wave device 1000 can form an overall symmetric electric field, thereby effectively ensuring that the surface acoustic wave device 1000 has a good excitation effect and improving the performance of the surface acoustic wave device 1000.

[0069] In some embodiments, the non-crossing region includes a second intermediate gap region, which is the region between the crossing region A0 and the second conductive strip 224. The metallization rate of the first finger portion 222 and / or the second finger portion 223 is ε1, and the metallization rate of the second intermediate gap region is ε3, where 0.8ε1 < ε3 < 1.2ε1. Since 0.8ε1 < ε3 < 1.2ε1, the surface acoustic wave device 1000 has high reliability and is not easy to burn out. The surface acoustic wave device 1000 is also not easy to be broken down because the positive and negative electrodes are too close. And it is easy to process, has a high sound velocity, and has a good energy suppression effect. Exemplarily, the second intermediate gap region is as shown in Figure 3 the intermediate gap region B1 in

[0070] Please refer to Figure 2 or Figure 3, in some embodiments, the size of the first conductive strip 221 in the first direction is W3, where 0.1λ < W3 < 0.3λ and λ is the wavelength of the surface acoustic wave device 1000. If W3 is too small, it is easy to cause the trace to burn out. If W3 is too large, the spurious mode suppression effect on the high-frequency side of the anti-resonant point will be reduced. 0.1λ < W3 < 0.3λ can balance reliability and a good spurious mode suppression effect. The spurious mode suppression effect on the high-frequency side of the anti-resonant point is good and it is not easy to cause the trace to burn out. In addition, it can also make the processing of the surface acoustic wave device 1000 easier.

[0071] Please refer to Figure 2 or Figure 3 , in some embodiments, the size of the first connection strip 21 in the first direction is L1, where 0.3λ < L1 < 2.5λ and λ is the wavelength of the surface acoustic wave device 1000. 0.3λ < L1 < 2.5λ, that is, the size of the first gap region B21 in the first direction is less than 2.5λ and greater than 0.3λ, so that the surface acoustic wave device 1000 has high reliability and is not easy to burn out. The surface acoustic wave device 1000 is also not easy to break down because its positive and negative poles are too close. And it is easy to process, has a high sound speed, and has a good energy suppression effect.

[0072] Please refer to Figure 2 or Figure 3 , in some embodiments, the axes of the first finger portions 222 of one resonator unit 22 and the first finger portions 222 of another resonator unit 22 coincide in the first direction, thereby ensuring that the surface acoustic wave device 1000 can have an overall symmetric electric field, and further effectively ensuring that the surface acoustic wave device 1000 has a good excitation effect and improving the performance of the surface acoustic wave device 1000.

[0073] Please refer to Figure 2 or Figure 3 , in some embodiments, the axes of the second finger portions 223 of one resonator unit 22 and the second finger portions 223 of another resonator unit 22 coincide in the first direction, thereby ensuring that the surface acoustic wave device 1000 can have an overall symmetric electric field, and further effectively ensuring that the surface acoustic wave device 1000 has a good excitation effect and improving the performance of the surface acoustic wave device 1000.

[0074] Please refer to Figure 2 or Figure 3 , in some embodiments, in the same resonator unit 22, the axis of the first connection strip 21 in the first direction coincides with the axis of one of the second finger portions 223 in the first direction, thereby ensuring that the surface acoustic wave device 1000 can have an overall symmetric electric field, and further effectively ensuring that the surface acoustic wave device 1000 has a good excitation effect and improving the performance of the surface acoustic wave device 1000.

[0075] Please refer to Figure 2 or Figure 3 In some embodiments, the two resonant units 22 are symmetrical about the connecting mechanism 30, so that the surface acoustic wave device 1000 can have an overall symmetrical electric field, thereby effectively ensuring that the surface acoustic wave device 1000 has a good excitation effect and improving the performance of the surface acoustic wave device 1000. For example, see Figure 2 , the two resonant units 22 are symmetrical about the second connecting bar 31. For another example, see Figure 3 The two resonant units 22 are symmetrical about the shared second conductive strip 224 .

[0076] The number of electrode units 20 of the surface acoustic wave device 1000 may include one, two, three or more. Figure 2 , the number of electrode units 20 is one. For example, see Figure 4 The number of electrode units 20 includes at least two, and each electrode unit 20 is disposed between two bus bars 10; in the second direction, each electrode unit 20 is disposed at intervals. One end of each electrode unit 20 is connected to the same first bus bar 11, and the other end of each electrode unit 20 is connected to the same second bus bar 12. Figure 4 , exemplarily, the number of electrode units 20 includes at least two, and at least two electrode units 20 are arranged at intervals along the second direction; wherein the two electrode units 20 are respectively located at the two lateral edges of the interdigital transducer 100 along the second direction, so as to ensure that the surface acoustic wave device 1000 has a good excitation effect and improve the performance of the surface acoustic wave device 1000. Exemplarily, the number of electrode units 20 includes at least two; in the same non-crossing area, the first conductive strips 221 of each electrode unit 20 are arranged at intervals along the second direction. Exemplarily, the number of electrode units 20 includes at least two; in the resonance units 22 of each electrode unit 20 located on the same side of the connecting mechanism 30 in the first direction, the second conductive strips 224 of each electrode unit 20 are arranged at intervals along the second direction. Exemplarily, the number of electrode units 20 includes at least two; the second connecting strips 31 of each electrode unit 20 are arranged at intervals along the second direction. In other embodiments, the number of electrode units 20 includes at least two; the first conductive strips 221 located on the same side of the connecting mechanism 30 in each electrode unit 20 are connected together in the second direction to form a continuous and uninterrupted structure; and / or, the second conductive strips 224 located on the same side of the connecting mechanism 30 in each electrode unit 20 are connected together in the second direction to form a continuous and uninterrupted structure; and / or, the second connecting strips 31 of each electrode unit 20 are connected together in the second direction to form a continuous and uninterrupted structure.

[0077] In some embodiments, in addition to the first finger portion 222 and the second finger portion 223 of the electrode unit 20, the IDT 100 does not include an electrode finger whose two ends are directly connected to the first bus bar 11 and the second bus bar 12. In other embodiments, in addition to the first finger portion 222 and the second finger portion 223 of the electrode unit 20, the IDT 100 may also include a plurality of electrode fingers whose two ends are directly connected to the first bus bar 11 and the second bus bar 12, respectively, and the plurality of electrode fingers are alternately arranged in the second direction.

[0078] See also Figure 2 In some embodiments, the edge area A2 is provided with a low sound velocity portion 40, and the sound velocity of the area provided with the low sound velocity portion 40 is less than the sound velocity of the middle area A1. The low sound velocity portion 40 can adjust the sound velocity of the area where the low sound velocity portion 40 is located, thereby adjusting the sound velocity distribution of the cross area A0, so that the sound velocity of the surface acoustic wave device 1000 can form a piston mode, thereby effectively suppressing the transverse mode. Exemplarily, the low sound velocity portion 40 may include at least one of the following structures: a widened portion, a thickened portion, and a mass loading structure. Exemplarily, the widened portion is a part of the first finger-line portion 222 or the second finger-line portion 223, that is, the widened portion is a portion of the first finger-line portion 222 or the second finger-line portion 223 located in the edge area A2 that is widened along the second direction compared to the portion of the finger-line portion located in the middle area A1. The thickened portion is a part of the first finger portion 222 or the second finger portion 223, that is, the thickened portion is a portion of the first finger portion 222 or the second finger portion 223 located in the edge area A2 that is thicker than the portion of the finger portion located in the middle area A1 along the top view direction. Exemplarily, the top view direction in this embodiment is perpendicular to the first direction and the second direction. The mass loading structure includes a mass loading block or a mass loading bar.

[0079] Figure 5 It is a comparison diagram of the admittance curves of the surface acoustic wave device 1000 of the related art and an embodiment of the present application, wherein the dotted line f1 is a schematic diagram of the admittance curve of the surface acoustic wave device 1000 of the related art; the dotted line f2 is a schematic diagram of the real part of the admittance curve of the surface acoustic wave device 1000 of the related art; the solid line g1 is a schematic diagram of the admittance curve of the surface acoustic wave device 1000 of an embodiment of the present application; and the solid line g2 is a schematic diagram of the real part of the admittance curve of the surface acoustic wave device 1000 of an embodiment of the present application. Figure 5 The horizontal axis is the frequency, in Hz; the vertical axis is the admittance, in dB. Figure 5 In the surface acoustic wave device 1000 of the embodiment of the present application, in the same electrode unit 20 , the number of the first connecting strips 21 connected to the resonance unit 22 is less than the number of the first finger strip portions 222 of the resonance unit 22 . Figure 5 In the surface acoustic wave device 1000 corresponding to the middle dashed line, the number of the first connecting strips 21 in the same electrode unit 20 is less than the number of the first finger strip portions 222. Figure 5 It can be seen that when the frequency is within the frequency interval from F1 to F2, the heterodyne mode of the surface acoustic wave device 1000 of the embodiment of the present application is significantly reduced compared with the surface acoustic wave device 1000 of the related art.

[0080] An embodiment of the present application further provides a filter, comprising the surface acoustic wave device 1000 of any one of the above embodiments.

[0081] Exemplarily, the filter includes a plurality of surface acoustic wave devices 1000, wherein at least one surface acoustic wave device 1000 includes the surface acoustic wave device 1000 of any of the above embodiments. The structures of the surface acoustic wave devices 1000 may be the same or different, which is not limited here.

[0082] An embodiment of the present application also provides a radio frequency front-end module, comprising the surface acoustic wave device 1000 of any one of the above embodiments.

[0083] In some embodiments, the RF front-end module is a component that integrates two or more discrete devices such as RF switches, low noise amplifiers, filters, duplexers, power amplifiers, etc. into an independent module, thereby improving integration and hardware performance and miniaturizing the volume. Exemplarily, the RF front-end module can be applied to electronic devices, and the electronic devices may include but are not limited to electronic devices or components with PCBs such as LED panels, tablet computers, notebooks, computers, navigators, mobile phones, and electronic watches, and this application does not limit this.

[0084] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "mechanically coupled" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the internal connection of two elements or the interaction relationship between two elements. The mechanical coupling or coupling of two components includes direct coupling and indirect coupling, for example, direct fixed connection, connection through a transmission mechanism, etc. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0085] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0086] The disclosure above provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described above. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0087] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific method steps, features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific method steps, features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0088] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A surface acoustic wave device, characterized in that: The surface acoustic wave device includes a piezoelectric substrate and interdigital transducers. The interdigital transducers are disposed on the piezoelectric substrate. The interdigital transducers include electrode units and two bus bars, and the two bus bars are arranged at intervals in a first direction. The electrode unit includes: A first connection bar; Two resonant units arranged in the first direction. The two resonant units are connected by the same connection mechanism. The resonant unit includes a first conductive bar, a first finger portion, a second finger portion, and a second conductive bar. The bus bar is connected to the first conductive bar through the first connection bar. The first conductive bar is connected to the first finger portion. The second finger portion is connected to the second conductive bar. The first finger portion and the second finger portion are arranged at intervals in a second direction perpendicular to the first direction. In the first direction, there are a crossover region and a non-crossover region between the two bus bars. The first connection bar and the first conductive bar are disposed in the non-crossover region. In the second direction, the crossover region is the region where the first finger portion and the second finger portion overlap each other. Wherein, in the same electrode unit, the number of the first connection bars connected to the resonant unit is less than the number of the first finger portions of the resonant unit.

2. The surface acoustic wave device according to claim 1, characterized in that: The frequencies of the two resonant units are the same.

3. The surface acoustic wave device according to claim 1, characterized in that: The second conductive bars of the two resonant units are arranged at intervals in the first direction. The connection mechanism includes: A second connection bar. The two ends of the second connection bar are respectively connected to the two second conductive bars. The number of the second connection bars is less than the number of the second finger portions connected to the second conductive bars.

4. The surface acoustic wave device according to claim 3, characterized in that: The non-crossover region includes a first intermediate gap region, which is the region between the two second conductive bars. The dimension of the first intermediate gap region in the first direction is F1, and 0.5λ < F1 < 2λ, where λ is the wavelength of the surface acoustic wave device.

5. The surface acoustic wave device according to claim 3, characterized in that: The dimension of the second conductive bar in the first direction is W1, and 0.1λ < W1 < 0.3λ, where λ is the wavelength of the surface acoustic wave device.

6. The surface acoustic wave device according to claim 3, characterized in that: The metallization rate of the first finger portion and / or the second finger portion is ε1, and the metallization rate of the first connection bar and / or the second connection bar is ε2, and 0.95ε1 < ε2 < 1.05ε1; and / or, the metallization rate of the first connection bar and / or the second connection bar is ε2, and 0.15 < ε2 < 0.

75.

7. The surface acoustic wave device according to claim 1, characterized in that: The two resonant units share one second conductive bar, and the connection mechanism includes the second conductive bar.

8. The surface acoustic wave device according to claim 7, characterized in that: The non-crossover region includes a second intermediate gap region, which is the region between the crossover region and the second conductive bar. The dimension of the second intermediate gap region in the first direction is F2, and 0.05λ < F2 < 0.5λ, where λ is the wavelength of the surface acoustic wave device.

9. The surface acoustic wave device according to claim 7, characterized in that: The dimension of the second conductive bar in the first direction is W2, and 0.2λ < W2 < 0.8λ, where λ is the wavelength of the surface acoustic wave device.

10. The surface acoustic wave device according to claim 7, characterized in that: The non-crossing region includes a second intermediate gap region, which is the region between the crossing region and the second conductive strip. The metallization rate of the first finger portion and / or the second finger portion is ε1, and the metallization rate of the second intermediate gap region is ε3, where 0.8ε1 < ε3 < 1.2ε1.

11. The surface acoustic wave device according to any one of claims 1 to 10, characterized in that: The size of the first conductive strip in the first direction is W3, where 0.1λ < W3 < 0.3λ, and λ is the wavelength of the surface acoustic wave device.

12. The surface acoustic wave device according to any one of claims 1 to 10, characterized in that: The size of the first connection strip in the first direction is L1, where 0.3λ < L1 < 2.5λ, and λ is the wavelength of the surface acoustic wave device.

13. The surface acoustic wave device according to any one of claims 1 to 10, characterized in that: The surface acoustic wave device has at least one of the following characteristics: The axes of the first finger portions of one of the resonant units and the first finger portions of another resonant unit coincide in the first direction; and / or, The axes of the second finger portions of one of the resonant units and the second finger portions of another resonant unit coincide in the first direction; and / or, In the same resonant unit, the axis of the first connection strip in the first direction coincides with the axis of one of the second finger portions in the first direction.

14. The surface acoustic wave device according to any one of claims 1 to 10, characterized in that: The two resonant units are axisymmetric with respect to the connection mechanism.

15. A filter, characterized in that: It includes the surface acoustic wave device according to any one of claims 1-14.

16. A radio frequency front-end module, characterized in that: It includes the surface acoustic wave device according to any one of claims 1-14.

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