Resonator, filter and radio frequency front-end module

Abstract

The invention relates to a resonator, a filter and a radio frequency front-end module. The resonator comprises a piezoelectric substrate and an interdigital transducer (10) arranged on the piezoelectric substrate. At least one electrode finger (2) in the interdigital transducer comprises a connecting part (21), a middle part (22) and a main body part (23) which are connected in sequence, the connecting part is connected to the bus bar (1), and the connecting part and the main body part are arranged on different sides of the middle part at intervals in the propagation direction of sound waves, so that a miscellaneous mode in a gap region can be inhibited to a certain extent, and the Q value is increased. In the arrangement direction of the two bus bars, the distance between the middle portion of the electrode finger and the bus bar connected with the electrode finger is H1, the distance between the middle portion of the electrode finger and the active area of the interdigital transducer is H2, H1 is smaller than or equal to H2, and the distance between the middle portion of the electrode finger and the adjacent electrode finger can be increased in the arrangement direction of the two bus bars. And the resonator has a larger electromechanical coupling coefficient and a higher Q value.

Description

[0001] This application is based on the Chinese application number 202311481113.3 filed on November 8, 2023 and entitled “Resonator, filter and RF front-end module”, and claims priority. Technical Field

[0002] The present application belongs to the field of radio frequency filtering technology, and in particular relates to a resonator, a filter and a radio frequency front-end module. Background Art

[0003] A surface acoustic wave (SAW) resonator is a device that converts an electrical signal into an acoustic signal or converts an acoustic signal into an electrical signal. A SAW resonator generally includes a piezoelectric substrate and an interdigital transducer (IDT). The IDT is formed on the piezoelectric substrate and can be used to convert an electrical signal into an acoustic signal or convert an acoustic signal into an electrical signal.

[0004] With the development of radio frequency technology, higher requirements are placed on the performance of resonators. How to further improve the Q value of SAW resonators has become an urgent problem to be solved. Summary of the invention

[0005] The present application provides a resonator, a filter and a radio frequency front-end module, aiming to improve the Q value of the SAW resonator.

[0006] In order to solve the above problems, an embodiment of the present application provides a resonator, including a piezoelectric substrate and an interdigital transducer arranged on the piezoelectric substrate; the interdigital transducer includes two bus bars and a plurality of electrode fingers; wherein the plurality of electrode fingers are located between the two bus bars; any one of the plurality of electrode fingers is connected to a bus bar and is spaced apart from another bus bar; the electrode fingers connected to different bus bars are arranged alternately and spaced apart in sequence; at least one electrode finger includes a connecting portion, an intermediate portion and a main body portion connected in sequence, the connecting portion is connected to the bus bar, and the connecting portion and the main body portion are spaced apart on different sides of the intermediate portion along the propagation direction of the sound wave; in the arrangement direction of the two bus bars, the spacing between the intermediate portion of the electrode finger and the bus bar to which it is connected is H1, and the spacing between the intermediate portion of the electrode finger and the active area of ​​the interdigital transducer is H2, wherein H1≤H2.

[0007] Optionally, in the arrangement direction of the two bus bars, the length of the middle portion of the electrode finger is H3, wherein λ

[0008] Optionally, 0.1λ<H3<0.3λ. ​

[0009] Optionally, at least one of the electrode fingers includes a first electrode finger, and the multiple electrode fingers include a second electrode finger, the second electrode finger is adjacent to the first electrode finger, and the connecting portion between the second electrode finger and the first electrode finger is located on the same side of the main body of the first electrode finger; in the propagation direction of the sound wave, the distance between the center line of the connecting portion of the first electrode finger and the center line of the first part of the second electrode finger is L1, wherein 0<L1<λ / 2, and the first part is located in the active area.

[0010] Optionally, in the arrangement direction of the two bus bars, the middle portion of the electrode finger does not overlap with the main body portion of the adjacent electrode finger.

[0011] Optionally, the angle between the extension direction of the connecting portion and the propagation direction of the sound wave is θ, wherein 21.8°<θ<158.2°.

[0012] Optionally, the resonator further includes a conductive structure, which is connected to the electrode fingers connected to the same bus bar; the conductive structure is located in a region between the active region and the middle portion, and is spaced apart from the active region and the middle portion.

[0013] Optionally, the resonator further includes a temperature compensation layer, and the temperature compensation layer covers the interdigital transducer.

[0014] Optionally, in the thickness direction of the piezoelectric substrate, the piezoelectric substrate comprises a substrate and a piezoelectric layer which are stacked; and the interdigital transducer is arranged on a surface of the piezoelectric layer which is away from the substrate.

[0015] Optionally, the temperature coefficient of the substrate is smaller than the temperature coefficient of the piezoelectric layer; and / or the thickness of the substrate is larger than the thickness of the piezoelectric layer; and / or the sound velocity of the substrate is larger than the sound velocity of the piezoelectric layer.

[0016] Optionally, the piezoelectric substrate further includes at least one dielectric layer disposed between the substrate and the piezoelectric layer; the thickness of the dielectric layer is less than the thickness of the substrate; and / or at least one of the dielectric layers includes at least a low sound velocity layer, the sound velocity of the low sound velocity layer being less than the sound velocity of the piezoelectric layer.

[0017] Optionally, in the arrangement direction of the two bus bars, the active area includes a middle area and edge areas located on both sides of the middle area; the interdigital transducer also includes a sound speed adjustment structure, which is used to make the propagation speed of the sound wave in the edge area smaller than the propagation speed in the middle area.

[0018] In order to solve the above problems, an embodiment of the present application also provides a resonator, including a piezoelectric substrate and an interdigital transducer arranged on the piezoelectric substrate; the interdigital transducer includes two bus bars and a plurality of electrode fingers; wherein the plurality of electrode fingers are located between the two bus bars; any one of the plurality of electrode fingers is connected to a bus bar and is spaced apart from another bus bar; the electrode fingers connected to different bus bars are arranged alternately and spaced apart in sequence; at least one electrode finger includes a connecting portion, an intermediate portion and a main body portion connected in sequence, the connecting portion is connected to the bus bar, and the connecting portion and the main body portion are spaced apart on different sides of the intermediate portion along the propagation direction of the sound wave; in the arrangement direction of the two bus bars, the intermediate portion of the electrode finger does not overlap with the main body portion of the adjacent electrode finger.

[0019] Optionally, at least one of the electrode fingers includes a first electrode finger, and the multiple electrode fingers include a second electrode finger, the second electrode finger is adjacent to the first electrode finger, and the connecting portion between the second electrode finger and the first electrode finger is located on the same side of the main body of the first electrode finger; in the propagation direction of the sound wave, the spacing between the center line of the connecting portion of the first electrode finger and the center line of the first part of the second electrode finger is L1, wherein DF*λ / 2<L1<λ / 2, the first part is located in the active area, and DF is the metallization ratio of the electrode fingers of the interdigital transducer.

[0020] Optional, H1≥H2.

[0021] Optionally, the angle between the extension direction of the connecting portion and the propagation direction of the sound wave is θ, 63.4°<θ<116.6°.

[0022] Optionally, the angle between the extension direction of the middle portion and the propagation direction of the sound wave is β, wherein 38.6°<β<141.4°, β≠90°.

[0023] In order to solve the above problems, an embodiment of the present application further provides a filter, comprising any one of the resonators described above.

[0024] In order to solve the above problems, an embodiment of the present application also provides a radio frequency front-end module, including the above filter.

[0025] In the resonator, filter and RF front-end module provided in the embodiment of the present application, at least one electrode finger is provided with a connecting portion, an intermediate portion and a main body portion, the connecting portion is connected to the bus bar, and the connecting portion and the main body portion are arranged at intervals on different sides of the intermediate portion along the propagation direction of the sound wave, so that the stray mode in the gap area can be suppressed to a certain extent and the Q value can be improved. In addition, by increasing the spacing between the intermediate portion of the electrode finger and its adjacent electrode finger in the arrangement direction of the two bus bars or in the propagation direction of the sound wave, the static capacitance of the resonator finger end can be effectively reduced, so that the resonator has a larger electromechanical coupling coefficient, and the energy leakage of the main mode caused by the parasitic coupling between the electrode finger having the connecting portion, the intermediate portion and the main body portion and its adjacent electrode finger is reduced, thereby further improving the Q value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of an interdigital transducer provided in Example 1 of the present application;

[0027] Figure 2 It is a structural schematic diagram of an interdigital transducer provided in the comparative example of the present application;

[0028] Figure 3 is a comparison diagram of the admittance curves of the resonator provided in Example 1 of the present application;

[0029] Figure 4 is a comparison chart of the quality factors of the resonators provided in Example 1 of the present application;

[0030] Figure 5 is a schematic diagram of the structure of the interdigital transducer provided in Example 6 of the present application;

[0031] Figure 6 is a schematic diagram of the structure of the interdigital transducer provided in Embodiment 7 of the present application;

[0032] Figure 7 is a schematic structural diagram of an interdigital transducer provided in Embodiment 8 of the present application;

[0033] Figure 8 is a comparison diagram of the admittance curves of the resonator provided in Example 8 of the present application;

[0034] Fig. 9 is a comparison chart of the quality factors of the resonators provided in the eighth embodiment of the present application;

[0035] Fig.10 is a schematic diagram of the structure of the interdigital transducer provided in Example 11 of the present application;

[0036] Fig.11 It is a schematic diagram of the structure of the interdigital transducer provided in Example 12 of the present application.

[0037] The reference numerals in the specification are as follows:

[0038] 10. Interdigital transducer;

[0039] 1. Bus bar; 11. First bus bar; 12. Second bus bar

[0040] 2. electrode finger; 21. connecting part; 22. middle part; 23. main body;

[0041] 3. Sound velocity adjustment structure;

[0042] 4. Conductive structure. DETAILED DESCRIPTION

[0043] In order to make the technical problems, technical solutions and beneficial effects solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0044] Embodiment 1

[0045] When the SAW resonator is working, it will generate gap zone stray modes, which will have an adverse effect on the performance of the SAW resonator, resulting in a decrease in the Q value of the SAW resonator, making the Q value of the SAW resonator unable to meet the growing demand. Among them, the gap zone stray modes refer to the stray modes generated in the gap zone.

[0046] In this regard, Figure 1 As shown, the first embodiment provides a resonator, which is a SAW resonator. The resonator includes a piezoelectric substrate and an IDT 10 . The IDT 10 is disposed on the piezoelectric substrate. The interdigital transducer 10 includes two bus bars 1 and a plurality of electrode fingers 2; wherein the plurality of electrode fingers 2 are all located between the two bus bars 1; any electrode finger 2 among the plurality of electrode fingers 2 is connected to a bus bar 1 and is spaced apart from another bus bar 1; the electrode fingers 2 connected to different bus bars 1 are arranged alternately and spaced apart in sequence; at least one electrode finger 2 includes a connecting portion 21, a middle portion 22 and a main body portion 23 connected in sequence, the connecting portion 21 is connected to the bus bar 1, and the connecting portion 21 and the main body portion 23 are spaced apart on different sides of the middle portion 22 along the propagation direction of the sound wave; in the arrangement direction of the two bus bars 1, the spacing between the middle portion 22 of the electrode finger 2 and the bus bar 1 to which it is connected is H1, and the spacing between the middle portion 22 of the electrode finger 2 and the active area a of the interdigital transducer 10 is H2, wherein H1≤H2.

[0047] "Multiple" means greater than or equal to two, and the word "multiple" has the same meaning in each embodiment and will not be repeated in the following text.

[0048] The propagation direction of the acoustic wave mainly refers to the propagation direction of the main mode of the acoustic wave, which can be parallel to the arrangement direction of each electrode finger 2, such as Figure 1 In the XY axis coordinate system shown, the propagation direction of the sound wave can be the direction of the X axis (hereinafter referred to as the X direction), that is, the lateral direction in the figure. The arrangement direction of the two bus bars 1 can be Figure 1 The direction of the Y axis in the figure (hereinafter referred to as the Y direction) is the longitudinal direction in the figure. The Y direction is orthogonal to the X direction.

[0049] The two bus bars 1 are defined as a first bus bar 11 and a second bus bar 12 , wherein a portion of the electrode fingers 2 are connected to the first bus bar 11 , and another portion of the electrode fingers 2 are connected to the second bus bar 12 .

[0050] Along the propagation direction of the acoustic wave, the area where the electrode fingers 2 overlap each other is the active area a. The area between the first bus bar 11 and the active area a is the gap area, and the area between the second bus bar 12 and the active area a is also the gap area.

[0051] The electrode finger 2 having a connecting portion 21, an intermediate portion 22 and a main portion 23 connected in sequence is defined as a bent electrode. The setting of the bent electrode can suppress the stray mode in the gap region to a certain extent and improve the Q value. The connecting portion 21 and the intermediate portion 22 of the bent electrode are both located in the gap region, a part of the main portion 23 of the bent electrode is located in the gap region, and the other part is located in the active region a.

[0052] In addition, in the scenario where a bent electrode is provided in the resonator, if the spacing between the bent electrode and its adjacent electrode finger is set small, it is easy to cause the static capacitance of the finger tip to increase, deteriorating the electromechanical coupling coefficient of the resonator, which is not conducive to the realization of a larger relative bandwidth filter. Moreover, in the scenario where the spacing between the bent electrode and its adjacent electrode finger 2 is small, the parasitic coupling between the bent electrode and its adjacent electrode finger 2 will cause the quality factor (Q value) above the main mode anti-resonance frequency to deteriorate, which is not conducive to the realization of low insertion loss.

[0053] The distance between the middle portion 22 of the bent electrode and the adjacent electrode finger 2 in the Y direction is relatively small, usually because H1 is set much larger than H2. Figure 2 , in this example, H1 is usually greater than H2.

[0054] In the present embodiment, H1 is set to be less than or equal to H2, which is equivalent to increasing the spacing between the middle portion 22 of the bent electrode and the adjacent electrode finger 2 in the Y direction, which can effectively reduce the static capacitance of the resonator finger tip and improve the electromechanical coupling coefficient of the resonator; moreover, H1 is set to be less than or equal to H2, which can also reduce the energy leakage of the main mode caused by the parasitic coupling between the bent electrode and its adjacent electrode finger 2 while ensuring the effect of the bent electrode on suppressing the stray mode in the gap area, thereby further improving the Q value.

[0055] refer to Figure 3 , Figure 3 is a comparison diagram of the admittance curves of the resonator of this embodiment and the resonator of the comparative example. Figure 2 In the example shown, except that the size relationship between H1 and H2 in the comparative example is different from that in the embodiment, other settings may be the same as those in the embodiment.

[0056] exist Figure 3 In the figure, the horizontal axis is frequency, the unit of frequency is GHz, the vertical axis is admittance, the unit of admittance is dB, and in addition, the solid line in the figure is the admittance curve of the present embodiment, and the dotted line is the admittance curve of the comparative example. Figure 3 It can be seen that the anti-resonance frequency fa of the embodiment is greater than the anti-resonance frequency fa of the comparative example, wherein the electromechanical coupling coefficient of the resonator of the embodiment can reach 8.53%, while the electromechanical coupling coefficient of the resonator of the comparative example can only reach 8.36%, which shows that the resonator of the embodiment has the effect of increasing the electromechanical coupling coefficient. Figure 3 It can be seen that the suppressing effect of the interstitial region stray modes in this embodiment and the comparative example is substantially the same.

[0057] refer to Figure 4 , Figure 4 is a comparison chart of the quality factors of the resonator of this embodiment and the resonator of the comparative example. Figure 2 In the example shown, except that the size relationship between H1 and H2 in the comparative example is different from that in the embodiment, other settings may be the same as those in the embodiment.

[0058] exist Figure 4 In the figure, the horizontal axis is the frequency, the unit of frequency is GHz, and the vertical axis is the quality factor (Q value). In addition, the solid line in the figure is the quality factor curve of the present embodiment, and the dotted line is the quality factor curve of the comparative example. Figure 4 It can be seen that the quality factor of this embodiment can be significantly improved.

[0059] The above-mentioned “connection portion 21 is connected to the bus bar 1” means: when the bent electrode is connected to the first bus bar 11, the connection portion 21 of the bent electrode is connected to the first bus bar 11; when the bent electrode is connected to the second bus bar 12, the connection portion 21 of the bent electrode is connected to the second bus bar 12.

[0060] The number of bent electrodes can be one or more. In the scenario where there are more than one bent electrodes, any one of the bent electrodes satisfies H1≤H2. The fact that the bent electrode satisfies H1≤H2 means that the spacing H1 between the middle portion 22 of the bent electrode and the bus bar 1 to which it is connected, and the spacing H2 between the middle portion 22 of the bent electrode and the active area a of the interdigital transducer 10 can satisfy H1≤H2. Of course, in the scenario where there are more than one bent electrode, only a part of the bent electrodes may satisfy H1≤H2.

[0061] In an exemplary embodiment, the material of the IDT 10 may be a single metal material or a composite or alloy material of different metals. Optionally, the material of the IDT 10 may be aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, etc., or a composite of the above metals or one of their alloys. In addition, the materials of the bus bar 1 and the electrode fingers 2 may be aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, etc., or a composite of the above metals or one of their alloys. The materials of the bus bar 1 and the electrode fingers 2 may be the same or different, and this application does not limit this.

[0062] In an exemplary embodiment, the busbar 1, the connecting portion 21, the middle portion 22 and the main body 23 can all be rectangular structures. Of course, any one of the busbar 1, the connecting portion 21, the middle portion 22 and the main body 23 can also be designed in other regular or irregular shapes, which is not limited in the present application.

[0063] In an exemplary embodiment, in the X direction, the widths of the electrode fingers 2 may be the same; or, in the X direction, the widths of at least two electrode fingers 2 may be different. In the scenario where the electrode finger 2 is a bent electrode, the width of the electrode finger 2 may refer to: in the X direction, the minimum value, maximum value, or average value of the width of the connecting portion 21 and the width of the main body 23 of the electrode finger 2.

[0064] For a bent electrode, the width of the connecting portion 21 in the X direction, the length of the middle portion 22 in the Y direction and the width of the main portion 23 in the X direction may be the same, or different, or only two of them may be the same.

[0065] In an exemplary embodiment, the extension directions of the two bus bars 1 may be arranged in parallel, and both of the extension directions may be parallel to the X direction. Of course, in the first embodiment, the extension directions of the two bus bars 1 may also be non-parallel.

[0066] In an exemplary embodiment, the extension direction of the connection portion 21 of the same bent electrode and the extension direction of the main body 23 thereof may be arranged in parallel. In this scenario, the extension directions of the two may be parallel to the Y direction or may not be parallel to the Y direction. Exemplarily, the extension directions of the two are parallel to the Y direction. In other embodiments, the extension direction of the connection portion 21 of the same bent electrode and the extension direction of the main body 23 thereof may also be non-parallel. In this scenario, the extension direction of the connection portion 21 may be parallel to the Y direction or may not be parallel to the Y direction; the extension direction of the main body 23 may be parallel to the Y direction or may not be parallel to the Y direction.

[0067] In an exemplary embodiment, the extending direction of the middle portion 22 of the bent electrode may be parallel to the X direction or may be non-parallel to the X direction. Exemplarily, the extending direction of the middle portion 22 is parallel to the X direction.

[0068] In an exemplary embodiment, the extension directions of two adjacent electrode fingers 2 are arranged in parallel. In the scenario where one of the two adjacent electrode fingers 2 is a bent electrode, the extension directions of both the connecting portion 21 and the main portion 23 of the bent electrode are parallel to the other electrode finger 2; in the scenario where two of the two adjacent electrode fingers 2 are bent electrodes, the extension directions of the connecting portions 21 of the two bent electrodes are parallel, the extension directions of the middle portions 22 of the two bent electrodes are parallel, and the extension directions of the main portions 23 of the two bent electrodes are parallel.

[0069] In an exemplary embodiment, in the thickness direction of the piezoelectric substrate, the piezoelectric substrate includes a substrate and a piezoelectric layer stacked in sequence; the interdigital transducer 10 is arranged on the surface of the piezoelectric layer away from the substrate. The longitudinal leakage of the acoustic wave energy can be suppressed by the substrate, thereby improving the Q value of the resonator. In addition, the thickness direction of the piezoelectric substrate refers to the arrangement direction of the piezoelectric substrate and the interdigital transducer 10, which is perpendicular to the X direction and perpendicular to the Y direction. For the substrate, its arrangement method can be a combination of one or more of the following exemplary embodiments:

[0070] In an exemplary embodiment, the material of the substrate includes at least one of monocrystalline silicon and polycrystalline silicon. Of course, the material of the substrate may also be other settings, for example, the material of the substrate may also be glass, spinel, aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, silicon oxynitride, DLC, silicon, sapphire, lithium tantalate, lithium niobate, quartz and other piezoelectrics, alumina, zirconium oxide, cordierite, mullite, talc, forsterite and other ceramics, diamond, magnesium oxide, or a material with the above materials as the main component, or a material with a mixture of the above materials as the main component, and this application does not limit it.

[0071] In an exemplary embodiment, the acoustic velocity of the substrate is greater than the acoustic velocity of the piezoelectric layer, where the acoustic velocity of the substrate refers to the propagation speed of acoustic waves in the substrate, and the acoustic velocity of the piezoelectric layer refers to the propagation speed of acoustic waves in the piezoelectric layer.

[0072] In an exemplary embodiment, the thickness of the substrate is greater than the thickness of the piezoelectric layer; the thickness of the piezoelectric layer refers to its dimension in the thickness direction of the piezoelectric substrate, and the thickness of the substrate refers to its dimension in the thickness direction of the piezoelectric substrate.

[0073] In an exemplary embodiment, a temperature coefficient of the substrate is less than a temperature coefficient of the piezoelectric layer.

[0074] In an exemplary embodiment, a dielectric layer may be provided between the substrate and the piezoelectric layer to improve the temperature characteristics and reduce the leakage of the main mode energy to the substrate. The dielectric layer may be provided in a manner that is a combination of one or more of the following exemplary embodiments:

[0075] In an exemplary embodiment, the number of the dielectric layer is at least one layer. When the number of the dielectric layer is multiple layers, each dielectric layer is sequentially stacked between the substrate and the piezoelectric layer along the thickness direction of the piezoelectric substrate.

[0076] In an exemplary embodiment, the thickness of the dielectric layer is less than the thickness of the substrate, wherein in the scenario where there are multiple dielectric layers, the thickness of any dielectric layer is less than the thickness of the substrate. In addition, the thickness of the dielectric layer refers to its dimension in the thickness direction of the piezoelectric substrate.

[0077] In an exemplary embodiment, at least one dielectric layer includes a low acoustic velocity layer, and the acoustic velocity of the low acoustic velocity layer is less than the acoustic velocity of the piezoelectric layer, so that the effect of suppressing the longitudinal leakage of low acoustic velocity acoustic wave energy can be improved. Among them, the material of the low acoustic velocity layer can be silicon oxide, etc. The acoustic velocity of the low acoustic velocity layer refers to the propagation speed of the acoustic wave in the low acoustic velocity layer. In addition, in the scenario where the number of dielectric layers is multiple, the number of low acoustic velocity layers can be only one or multiple.

[0078] It is understandable that the material of the piezoelectric layer includes at least one of lithium niobate and lithium tantalate. Of course, the material of the piezoelectric layer can also be other settings, for example, the material of the piezoelectric layer can also be at least one of quartz, sapphire and other materials. In addition, the material of the piezoelectric layer can also be other materials with piezoelectric properties, which is not limited in this application.

[0079] It should be understood that in other embodiments, the piezoelectric substrate may also have only a piezoelectric layer. In this embodiment, the piezoelectric layer may have only one layer or multiple layers. In addition, in the scenario where the piezoelectric substrate has multiple layers of piezoelectric layers, the materials of any two piezoelectric layers may be the same or different. In an exemplary embodiment, Figure 1 As shown, in the arrangement direction of the two bus bars 1, the active area a includes a middle area a1 and edge areas a2 located on both sides of the middle area a1; the interdigital transducer 10 also includes a sound velocity adjustment structure 3, which is used to make the propagation speed of the sound wave in the edge area a2 smaller than the propagation speed in the middle area a1. In this way, a piston structure can be formed in the edge area a2 to suppress the lateral heterogeneous mode generated by the resonator, reduce energy loss, and further improve the Q value of the resonator.

[0080] For the relative position between the sound velocity adjustment structure 3 and the electrode finger 2, there are several possible implementations as follows:

[0081] In an exemplary embodiment, the sound velocity regulating structure 3 may be arranged in the thickness direction of the electrode finger 2. In this manner, the electrode finger 2 is equivalent to being thickened. Specifically, the sound velocity regulating structure 3 may be located above the electrode finger 2, or below the electrode finger 2, or both above and below the electrode finger 2.

[0082] In an exemplary embodiment, the sound velocity regulating structure 3 may also be arranged in the width direction of the electrode finger 2. In this manner, the electrode finger 2 is equivalent to being widened. Specifically, the sound velocity regulating structure 3 may be located on one side in the width direction of the electrode finger 2, or may be located on both sides in the width direction of the electrode finger 2.

[0083] In an exemplary embodiment, the sound velocity regulating structure 3 may also be provided in both the thickness direction and the width direction of the electrode finger 2. In this manner, the electrode finger 2 is equivalent to being thickened and widened. In addition, the sound velocity regulating structure 3 may be in direct contact with the electrode finger 2, or the sound velocity regulating structure 3 and the electrode finger 2 may be separated by other membrane layers, wherein the membrane layer used to separate the sound velocity regulating structure 3 and the electrode finger 2 may be at least one of a temperature compensation layer and a frequency modulation layer.

[0084] The thickness direction of the electrode finger 2 is the same as the thickness direction of the piezoelectric substrate, and the width direction of the electrode finger 2 is the same as the propagation direction of the sound wave. In addition, the sound velocity adjustment structure 3 is located above the electrode finger 2, which means that the sound velocity adjustment structure 3 is located on the side of the electrode finger 2 away from the piezoelectric substrate, and the sound velocity adjustment structure 3 is located below the electrode finger 2, which means that the sound velocity adjustment structure 3 is located between the electrode finger 2 and the piezoelectric substrate.

[0085] In addition, the sound velocity adjustment structure 3 can adjust the sound velocity in the following ways:

[0086] In an exemplary embodiment, the sound speed regulating structure 3 is a low sound speed structure, and the sound speed regulating structure 3 is arranged in the edge area a2 to reduce the sound speed of the edge area a2, thereby making the sound speed of the edge area a2 smaller than the sound speed of the middle area a1.

[0087] By providing the low-sound-velocity structure, a piston structure can be formed in the edge region a2 to better suppress the transverse mode.

[0088] In addition, the material of the low sound velocity structure can be a single metal or a composite or alloy of different metals. Optionally, the material of the low sound velocity structure can be one of molybdenum, tungsten, ruthenium, gold, magnesium, aluminum, copper, chromium, titanium, osmium, iridium or a composite or alloy of the above metals. Of course, the material of the sound velocity adjustment structure 3 can also be a dielectric material, such as tantalum oxide.

[0089] In another exemplary embodiment, the sound velocity adjustment structure 3 may be a high sound velocity structure, and the sound velocity adjustment structure 3 is arranged in the middle area a1 to increase the sound velocity of the middle area a1, thereby making the sound velocity of the edge area a2 smaller than the sound velocity of the middle area a1, and this method can also suppress the lateral mode. In addition, the material of the high sound velocity structure may be any one or more of silicon nitride, aluminum oxide and silicon carbide.

[0090] In another exemplary embodiment, the sound velocity adjustment structure 3 may also include a low sound velocity structure and a high sound velocity structure, wherein the low sound velocity structure is arranged in the edge area a2, and the high sound velocity structure is arranged in the middle area a1.

[0091] It should be understood that in the first embodiment, the sound velocity adjustment structure 3 may not be provided in the resonator.

[0092] In an exemplary embodiment, the resonator further includes a temperature compensation layer, and the temperature compensation layer covers the IDT 10, wherein the temperature compensation layer covers the IDT 10, which may mean that in the orthographic projection of the upper surface of the piezoelectric substrate (the upper surface of the piezoelectric substrate is a plane), the projection of the temperature compensation layer and the projection of the IDT 10 have an overlapping area. The temperature compensation layer may completely cover the IDT 10, or may only cover a portion of the IDT 10. The temperature compensation layer is used to improve the temperature characteristics of the resonator, and the material of the temperature compensation layer may be one of dielectrics such as silicon oxide, silicon nitride, silicon oxynitride, or a mixture of any of them.

[0093] In the scenario where the temperature compensation layer completely covers the IDT 10, in the orthographic projection of the upper surface of the piezoelectric substrate, the projection of the IDT 10 is completely located within the projection of the temperature compensation layer. In the scenario where the temperature compensation layer only covers a portion of the IDT 10, in the orthographic projection of the upper surface of the piezoelectric substrate, a portion of the projection of the IDT 10 is located within the projection of the temperature compensation layer, and another portion is located outside the projection of the temperature compensation layer.

[0094] Of course, in the first embodiment, the temperature compensation layer may not be provided in the resonator.

[0095] Embodiment 2

[0096] Embodiment 2 is an improvement on Embodiment 1. Specifically, in Embodiment 2, in the arrangement direction of the two bus bars 1, the length of the middle portion 22 of the electrode finger 2 is H3, wherein λ

[0097] Embodiment 3

[0098] Embodiment 3 is an improvement on embodiment 2. Specifically, in embodiment 3, 0.1λ<H3<0.3λ. Such a setting can further improve the suppression effect on the stray modes in the gap region, so that the resonator can have a higher Q value. Moreover, in this embodiment, within the range of λ

[0099] Embodiment 4

[0100] Embodiment 4 is an improved solution made on the basis of any one of Embodiment 1, Embodiment 2 and Embodiment 3. Specifically, in Embodiment 4, at least one electrode finger 2 includes a first electrode finger (that is, the first electrode finger is any bent electrode finger), and the plurality of electrode fingers 2 include a second electrode finger, the second electrode finger is adjacent to the first electrode finger, and the connecting portion 21 of the second electrode finger and the first electrode finger is located on the same side of the main body 23 of the first electrode finger; in the propagation direction of the sound wave, the distance between the center line of the connecting portion 21 of the first electrode finger and the center line of the first part of the second electrode finger is L1 (reference Figure 1 ), wherein 0<L1<λ / 2, and the first part is located in the active area a.

[0101] It can be understood that when H1 is less than or equal to H2, 0<L1<λ / 2 is defined, that is, the connecting portion of the first electrode finger may partially overlap with the first portion of the second electrode finger, which may also reduce the terminal capacitance of the electrode finger to a certain extent.

[0102] ​​The first part is a part of the second electrode in its own extension direction, and the center line of the first part is the center line of the part of the second electrode finger located in the active area a. In this embodiment, on the premise of increasing the spacing between the middle part 22 of the bent electrode and its adjacent electrode finger 2 in the Y direction, the spacing between adjacent electrode fingers in the X direction is further increased, so that the finger-end static capacitance and parasitic coupling between adjacent electrode fingers can be further reduced, so that the resonator has a larger electromechanical coupling coefficient and a higher Q value.

[0103] The first plane is defined as a surface perpendicular to the thickness direction of the piezoelectric substrate, that is, the first plane is a plane parallel to the X-axis and the Y-axis in the square coordinate axis. The center line of the connection portion 21 of the first electrode finger may refer to the midline (the midline is defined as the first midline) of the orthographic projection (the projection is defined as the first projection) of the connection portion 21 of the first electrode finger on the first plane, and the first midline is parallel to the Y direction. In the X direction, the first projection is divided into two parts by the first midline, and the two parts are symmetrical with respect to the first midline.

[0104] The center line of the first part may refer to the midline (the midline is defined as the second midline) of the orthographic projection of the first part on the first plane (the projection is defined as the second projection), and the second midline is parallel to the Y direction. In the X direction, the second projection is divided into two parts by the second midline, and the two parts are symmetrical with respect to the second midline.

[0105] In an exemplary embodiment, the extension direction of the connection portion 21 of the first electrode finger may be parallel to the extension direction of the first portion, and both extension directions may be parallel to the Y direction. In addition, in the fourth embodiment, the width of the connection portion 21 of the first electrode finger in the X direction may be equal to the width of the first portion in the X direction. Moreover, the width of the first electrode finger in the X direction may also be equal to the width of the second electrode finger in the X direction. Of course, in the fourth embodiment, the width of the connection portion 21 of the first electrode finger in the X direction may be greater than or less than the width of the first portion in the X direction.

[0106] In an exemplary embodiment, the first electrode finger is a bent electrode, and the second electrode finger may be a bent electrode or may not be a bent electrode. In the scenario where the second electrode finger is a bent electrode, the first portion may be the main body 23 of the second electrode finger.

[0107] In an exemplary embodiment, in the propagation direction of the sound wave, the distance between the connecting portion 21 of the first electrode finger and the main body 23 of the first electrode finger is greater than the distance between the first portion and the main body 23 of the first electrode finger, or, in the propagation direction of the sound wave, the distance between the connecting portion 21 of the first electrode finger and the main body 23 of the first electrode finger may also be smaller than the distance between the first portion and the main body 23 of the first electrode finger.

[0108] Embodiment 5

[0109] Embodiment 5 is an improved solution based on any one of Embodiment 1, Embodiment 2 and Embodiment 3. Specifically, in Embodiment 5, in the arrangement direction of the two bus bars 1, the middle portion 22 of the electrode finger 2 does not overlap with the main portion 23 of the adjacent electrode finger 2. This arrangement can also increase the spacing between adjacent electrode fingers 2 in the X direction while increasing the spacing between the middle portion 22 of the bent electrode and its adjacent electrode finger 2 in the Y direction, so that the resonator has a larger electromechanical coupling coefficient and a higher Q value.

[0110] In the fifth embodiment, in the arrangement direction of the two bus bars 1, the middle portion 22 of the electrode finger 2 does not overlap with the main portion 23 of the adjacent electrode finger 2, which may mean that in the orthographic projection of a plane perpendicular to the Y direction, the projection of the middle portion 22 of the electrode finger 2 (the projection is defined as the third projection) does not overlap with the projection of the main portion 23 of the adjacent electrode finger 2 (the projection is defined as the fourth projection). The third projection and the fourth projection may be arranged at intervals, or the edges of the third projection and the fourth projection may overlap, that is, the spacing between the two is 0.

[0111] Embodiment 6

[0112] Embodiment 6 is an improved solution based on any one of Embodiment 1, Embodiment 2 and Embodiment 3. For details, refer to Figure 5 In the sixth embodiment, the angle between the extension direction of the connection portion 21 and the propagation direction of the sound wave is θ, wherein 21.8°<θ<158.2°, and such a setting can improve the suppression effect of the stray mode in the gap region, thereby further improving the Q value. Specifically, the value of θ can be 25°, 30°, 60°, 90°, 120°, 150°, etc.

[0113] In an exemplary embodiment, the extension direction of the two bus bars 1 is parallel to the X direction, the extension direction of the main body 23 of the electrode finger 2 is parallel to the Y direction, the extension direction of the middle portion 22 is parallel to the X direction, and the extension direction of the connecting portion 21 can be parallel to the Y direction (i.e., θ=90°), or it can form an angle other than 90° within the above range, that is, the connecting portion 21 can be perpendicular to the bus bar 1, or inclined to the left, or inclined to the right, and the present application does not make specific limitations.

[0114] Embodiment 7

[0115] Embodiment 7 is an improved solution based on Embodiment 6. For details, refer to Figure 6In the seventh embodiment, the resonator further includes a conductive structure 4, which is connected to the electrode fingers 2 connected to the same bus bar 1; the conductive structure 4 is located in the area between the active area a and the middle part 22, and is spaced apart from the active area a and the middle part 22. This will also reduce the parasitic coupling between two adjacent electrode fingers 2 to a certain extent, thereby further improving the Q value. Moreover, such a setting can also reduce the resistance, thereby reducing the device loss.

[0116] In the seventh embodiment, after the conductive structure 4 is connected to the electrode finger 2, the two are electrically connected. The conductive structure 4 may be connected to all electrode fingers 2 connected to the same bus bar 1, or the conductive structure 4 may be connected to a part of all electrode fingers 2 connected to the same bus bar 1, so as to short-circuit the electrode fingers 2 together.

[0117] In an exemplary embodiment, the extension direction of the conductive structure 4 is parallel to the X direction. In an exemplary embodiment, the extension direction of the conductive structure 4 is parallel to the extension direction of the busbar 1 .

[0118] It can be understood that the conductive structure 4 can be arranged between the first bus bar 11 and the active area a, and the conductive structure 4 is connected to the electrode finger 2 connected to the first bus bar 11; and / or the conductive structure 4 is arranged between the second bus bar 12 and the active area a, and the conductive structure 4 is connected to the electrode finger 2 connected to the second bus bar 12. The number of the conductive structures 4 can be one or more; in the manner in which the number of the conductive structures 4 is more than one, the conductive structures 4 are arranged in sequence and spaced apart along the Y direction.

[0119] The conductive structure 4 may be made of a single metal or a composite or alloy of different metals. Optionally, the conductive structure 4 may be made of molybdenum, tungsten, ruthenium, gold, magnesium, aluminum, copper, chromium, titanium, osmium, iridium or a composite or alloy of the above metals.

[0120] Embodiment 8

[0121] like Figure 7As shown, in Example 8, the resonator includes a piezoelectric substrate and an IDT 10 arranged on the piezoelectric substrate; the IDT 10 includes two bus bars 1 and a plurality of electrode fingers 2; wherein the plurality of electrode fingers 2 are located between the two bus bars 1; any electrode finger 2 among the plurality of electrode fingers 2 is connected to a bus bar 1 and is spaced apart from another bus bar 1; the electrode fingers 2 connected to different bus bars 1 are arranged alternately and spaced apart in sequence; at least one electrode finger 2 includes a connecting portion 21, an intermediate portion 22 and a main body portion 23 connected in sequence, the connecting portion 21 is connected to the bus bar 1, and the connecting portion 21 and the main body portion 23 are spaced apart on different sides of the intermediate portion 22 along the propagation direction of the sound wave; in the arrangement direction of the two bus bars 1, the intermediate portion 22 of the electrode finger 2 does not overlap with the main body portion 23 of the adjacent electrode finger 2.

[0122] The difference between the eighth embodiment and the first embodiment is that in the eighth embodiment, without considering the spacing relationship between the middle portion 22 of the electrode finger 2 and the main portion 23 of the adjacent electrode finger 2 in the Y direction, the spacing between the two in the X direction is increased, so that the static capacitance between the middle portion 22 of the bent electrode and the adjacent electrode finger 2 can be reduced to improve the electromechanical coupling coefficient of the resonator, and the parasitic coupling between the bent electrode and the adjacent electrode finger 2 can be reduced to improve the Q value. In the eighth embodiment, whether H≤H2 or H1>H2, the electromechanical coupling coefficient of the resonator can be improved and the Q value can be increased.

[0123] Except for the above differences, other settings in the eighth embodiment may be the same as those in the first embodiment.

[0124] In addition, the corresponding improvements in the above-mentioned Embodiment 2, Embodiment 3, Embodiment 4, Embodiment 6 and Embodiment 7 can also be applied to Embodiment 8.

[0125] Embodiment 9

[0126] Embodiment 9 is an improved solution based on Embodiment 8. Specifically, at least one electrode finger 2 includes a first electrode finger, and the plurality of electrode fingers 2 include a second electrode finger. The second electrode finger is adjacent to the first electrode finger, and the connecting portion 21 of the second electrode finger and the first electrode finger is located on the same side of the main body 23 of the first electrode finger 2. In the propagation direction of the acoustic wave, the distance between the center line of the connecting portion 21 of the first electrode finger and the center line of the first part of the second electrode finger is L1 (reference Figure 7 ), wherein DF*λ / 2<L1<λ / 2, the first part is located in the active region a, and DF is the metallization of the electrode finger 2 of the interdigital transducer 10. This arrangement can increase the spacing between the bent electrode and its adjacent electrode finger in the X direction, improve the electromechanical coupling coefficient and Q value of the resonator, and avoid excessive polarization voltage caused by excessive spacing between the two in the X direction.

[0127] The following differences exist between the ninth embodiment and the fourth embodiment: Difference 1: The improvement bases of the two embodiments are different. Specifically, the fourth embodiment is made on the basis of any one of the first embodiment, the second embodiment and the third embodiment, while the ninth embodiment is made on the basis of the eighth embodiment; Difference 2: The value ranges of L1 in the two embodiments are different. In addition, other settings in the ninth embodiment may be the same as those in the fourth embodiment.

[0128] Embodiment 10

[0129] Embodiment 10 is an improved solution based on Embodiment 8. For details, refer to Figure 7 In the tenth embodiment, H1≥H2, which can improve the suppression effect of the heterogeneous mode in the gap area.

[0130] Among them, in the tenth embodiment, the number of bent electrodes can be one or more. In the scenario where the number of bent electrodes is multiple, any bent electrode satisfies H1≥H2, wherein the bent electrode satisfies H1≥H2 means that the spacing H1 between the middle portion 22 of the bent electrode and the bus bar 1 to which it is connected, and the spacing H2 between the middle portion 22 of the bent electrode and the active area a of the interdigital transducer 10 can satisfy H1≥H2; or, in the scenario where the number of bent electrodes is multiple, only a part of the bent electrodes can satisfy H1≥H2.

[0131] refer to Figure 8 , Figure 8 is a comparison diagram of the admittance curves of the resonator of this embodiment and the resonator of the comparative example. Figure 2 In the example shown, except for the difference that “the middle portion 22 of the electrode finger 2 overlaps with the main portion 23 of the adjacent electrode finger 2 ”, the other configurations in the comparative example may be the same as those in the present embodiment.

[0132] exist Figure 8 In the figure, the horizontal axis is frequency, the unit of frequency is GHz, the vertical axis is admittance, the unit of admittance is dB, and in addition, the solid line in the figure is the admittance curve of the present embodiment, and the dotted line is the admittance curve of the comparative example. Figure 8 It can be seen from the right side view that the anti-resonance frequency fa of the embodiment is slightly greater than the anti-resonance frequency fa of the comparative example. The electromechanical coupling coefficient of the resonator of the embodiment can reach 8.42%, while the electromechanical coupling coefficient of the resonator of the comparative example can only reach 8.36%. It can be seen that the resonator of the embodiment has the effect of increasing the electromechanical coupling coefficient. Figure 8 In the figure, the right view is the enlarged view in the rectangular frame of the left view. Figure 8 It can be seen that the suppressing effect of the interstitial region stray modes in this embodiment and the comparative example is substantially the same.

[0133] refer to Fig. 9 , Fig. 9 is a comparison chart of the quality factors of the resonator of this embodiment and the resonator of the comparative example. Figure 2 In the example shown, except for the difference that “the middle portion 22 of the electrode finger 2 overlaps with the main portion 23 of the adjacent electrode finger 2 ”, the other configurations in the comparative example may be the same as those in the present embodiment.

[0134] exist Fig. 9 In the figure, the horizontal axis is the frequency, the unit of frequency is GHz, and the vertical axis is the quality factor (Q value). In addition, the solid line in the figure is the quality factor curve of the present embodiment, and the dotted line is the quality factor curve of the comparative example. Fig. 9 It can be seen that the quality factor of this embodiment can be significantly improved.

[0135] Embodiment 11

[0136] Embodiment 11 is an improved solution based on Embodiment 10. For details, refer to Fig.10 In the eleventh embodiment, the angle between the extension direction of the connection portion 21 and the propagation direction of the sound wave is θ, 63.4°<θ<116.6°, and this setting can further improve the suppression effect of the stray mode in the gap area. Specifically, the size of θ can be 80°, 90°, 100°, 110°, etc.

[0137] In an exemplary embodiment, the extension direction of the two bus bars 1 is parallel to the X direction, the extension direction of the main body 23 of the electrode finger 2 is parallel to the Y direction, the extension direction of the middle portion 22 is parallel to the X direction, and the extension direction of the connecting portion 21 can be parallel to the Y direction (i.e., θ=90°), or it can form an angle other than 90° within the above range, that is, the connecting portion 21 can be perpendicular to the bus bar 1, or inclined to the left, or inclined to the right, and the present application does not make specific limitations.

[0138] Embodiment 12

[0139] Embodiment 12 is an improved solution based on Embodiment 10. For details, refer to Fig.11 In the twelfth embodiment, the angle between the extension direction of the middle portion 22 and the propagation direction of the sound wave is β, wherein 38.6°<β<141.4°, β≠90°, and this arrangement can also reduce the static capacitance and parasitic coupling between the middle portion of the electrode finger and its adjacent electrode finger, thereby further improving the electromechanical coupling coefficient and Q value of the resonator. Specifically, the size of β can be 40°, 60°, 100°, 120°, 140°, etc.

[0140] In an exemplary embodiment, the extension direction of the middle portion 22 is parallel to the propagation direction of the sound wave (X direction), and the extension direction of the main body portion 23 of the electrode finger 2 is parallel to the Y direction. In this embodiment, the extension direction of the middle portion 22 forms an angle with the propagation direction of the sound wave, and does not include the case of being orthogonal to the X direction. In other words, the middle portion 22 can be tilted to the left or to the right, and this application does not make specific limitations.

[0141] The present application also provides a filter, which includes the resonator described in any of the above embodiments. The number of resonators included in the filter can be one or more. In the scenario where the filter includes multiple resonators, each resonator can be connected in series with each other, or each resonator can be connected in parallel, or a part of each resonator is a series arm resonator and the other part is a parallel arm resonator.

[0142] The present application also provides a radio frequency front-end module, which includes the filter described in any of the above embodiments. The radio frequency front-end module may also include antennas, switches, power amplifiers, low noise amplifiers, capacitors, inductors and other devices, which are not described in detail in the embodiments of the present application.

[0143] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0144] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A resonator, wherein: It includes a piezoelectric substrate and an interdigital transducer arranged on the piezoelectric substrate; The interdigital transducer comprises two bus bars and a plurality of electrode fingers; wherein the plurality of electrode fingers are located between the two bus bars; any one of the plurality of electrode fingers is connected to a bus bar and is spaced apart from another bus bar; the electrode fingers connected to different bus bars are arranged alternately and spaced apart in sequence; At least one of the electrode fingers comprises a connecting portion, an intermediate portion and a main portion which are connected in sequence, the connecting portion is connected to the bus bar, and the connecting portion and the main portion are arranged at different sides of the intermediate portion at intervals along a propagation direction of the sound wave; In the arrangement direction of the two bus bars, the distance between the middle portion of the electrode finger and the bus bar connected thereto is H1, and the distance between the middle portion of the electrode finger and the active area of ​​the IDT is H2, wherein H1≤H2.

2. The resonator according to claim 1, wherein In the arrangement direction of the two bus bars, the length of the middle portion of the electrode finger is H3, wherein λ<H1+H2+H3<3λ, and λ is the period of the sound wave.

3. The resonator according to claim 2, wherein: 0.1λ<H3<0.3λ.

4. The resonator according to any one of claims 1 to 3, wherein: The at least one electrode finger includes a first electrode finger, the multiple electrode fingers include a second electrode finger, the second electrode finger is adjacent to the first electrode finger, and the connecting portion between the second electrode finger and the first electrode finger is located on the same side of the main body of the first electrode finger; in the propagation direction of the sound wave, the distance between the center line of the connecting portion of the first electrode finger and the center line of the first part of the second electrode finger is L1, wherein 0<L1<λ / 2, and the first part is located in the active area.

5. The resonator according to any one of claims 1 to 3, wherein: In the arrangement direction of the two bus bars, the middle portion of the electrode finger does not overlap with the main portion of the adjacent electrode finger.

6. The resonator according to any one of claims 1 to 3, wherein: The angle between the extension direction of the connecting portion and the propagation direction of the sound wave is θ, wherein 21.8°<θ<158.2°.

7. The resonator according to claim 6, wherein: The resonator further includes a conductive structure connected to the electrode fingers connected to the same bus bar; the conductive structure is located in a region between the active region and the middle portion and is spaced apart from the active region and the middle portion.

8. The resonator according to claim 1, wherein The resonator further includes a temperature compensation layer covering the interdigital transducer.

9. The resonator according to claim 1, wherein: In the thickness direction of the piezoelectric substrate, the piezoelectric substrate includes a substrate and a piezoelectric layer stacked in layers; The interdigital transducer is disposed on a surface of the piezoelectric layer facing away from the substrate.

10. The resonator according to claim 9, wherein The temperature coefficient of the substrate is smaller than the temperature coefficient of the piezoelectric layer; and / or, The thickness of the substrate is greater than the thickness of the piezoelectric layer; and / or, The acoustic velocity of the substrate is greater than the acoustic velocity of the piezoelectric layer.

11. The resonator according to claim 9, wherein The piezoelectric substrate further comprises at least one dielectric layer disposed between the substrate and the piezoelectric layer; The thickness of the dielectric layer is smaller than the thickness of the substrate; and / or, At least one of the dielectric layers includes at least a low acoustic velocity layer, and the acoustic velocity of the low acoustic velocity layer is lower than the acoustic velocity of the piezoelectric layer.

12. The resonator according to claim 1, wherein In the arrangement direction of the two bus bars, the active area includes a middle area and edge areas located on both sides of the middle area; The IDT further comprises a sound velocity adjustment structure, which is used to make the propagation velocity of the sound wave in the edge region smaller than the propagation velocity in the middle region.

13. A resonator, wherein: It includes a piezoelectric substrate and an interdigital transducer arranged on the piezoelectric substrate; The interdigital transducer comprises two bus bars and a plurality of electrode fingers; wherein the plurality of electrode fingers are located between the two bus bars; any one of the plurality of electrode fingers is connected to a bus bar and is spaced apart from another bus bar; the electrode fingers connected to different bus bars are arranged alternately and spaced apart in sequence; At least one of the electrode fingers comprises a connecting portion, an intermediate portion and a main portion which are connected in sequence, the connecting portion is connected to the bus bar, and the connecting portion and the main portion are arranged at different sides of the intermediate portion at intervals along a propagation direction of the sound wave; In the arrangement direction of the two bus bars, the middle portion of the electrode finger does not overlap with the main portion of the adjacent electrode finger.

14. The resonator according to claim 13, wherein: The at least one electrode finger includes a first electrode finger, the multiple electrode fingers include a second electrode finger, the second electrode finger is adjacent to the first electrode finger, and the connecting portion between the second electrode finger and the first electrode finger is located on the same side of the main body of the first electrode finger; in the propagation direction of the sound wave, the distance between the center line of the connecting portion of the first electrode finger and the center line of the first part of the second electrode finger is L1, wherein DF*λ / 2<L1<λ / 2, the first part is located in the active area, and DF is the metallization ratio of the electrode fingers of the interdigital transducer.

15. The resonator according to claim 13, wherein: H1≥H2.

16. The resonator according to claim 15, wherein The included angle between the extension direction of the connecting portion and the propagation direction of the sound wave is θ, 63.4°<θ<116.6°.

17. The resonator according to claim 15, wherein The included angle between the extension direction of the middle portion and the propagation direction of the sound wave is β, wherein 38.6°<β<141.4°, β≠90°.

18. A filter, wherein: A resonator comprising any one of claims 1-17.

19. A radio frequency front-end module, wherein: Comprising the filter as claimed in claim 18.

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