Resonator, filter and radio frequency front-end module

Abstract

The invention is applicable to the technical field of radio frequency filtering, and discloses a resonator, a filter and a radio frequency front-end module, the resonator comprises a piezoelectric substrate and an interdigital transducer arranged on the piezoelectric substrate, the interdigital transducer comprises at least two bus bars, the at least two bus bars are arranged on the piezoelectric substrate along a first direction, and the at least two bus bars are arranged on the piezoelectric substrate along a second direction. The bus bars are electrically connected with the electrode fingers respectively, the electrode fingers between every two adjacent bus bars are sequentially and alternately arranged at intervals in the second direction to form intersection areas and gap areas, each electrode finger comprises a main body piece and a connecting piece located between the main body piece and the corresponding bus bar, the main body pieces are located in the intersection areas, and the connecting pieces are located between the main body pieces and the bus bars. The connecting piece is located in the gap area and connected to one bus bar. The main body piece comprises a plurality of main body parts, in the same electrode finger, the plurality of main body parts are sequentially connected in the first direction, and the included angle between every two adjacent main body parts is an obtuse angle. According to the embodiment of the invention, the numerical value of the electromechanical coupling coefficient of the resonator can be effectively controlled, so as to better adapt to the design requirements of the surface acoustic wave filter.

Description

Technical Field

[0001] This application relates to the field of radio frequency filtering technology, and in particular to a resonator, filter and radio frequency front-end module. Background Technology

[0002] Surface acoustic wave (SAW) devices consist of a piezoelectric substrate and interdigital transducers disposed on the piezoelectric substrate. The interdigital transducers are used to convert electrical signals into acoustic signals or vice versa. With the development of radio frequency technology, higher requirements have been placed on SAW devices, such as achieving higher rectangularity in SAW devices with wider bandwidths.

[0003] In related technologies, methods for adjusting the bandwidth of surface acoustic wave (SAW) devices include selecting piezoelectric substrates with different tangential orientations and materials to achieve the target bandwidth and adjust the electromechanical coupling coefficient. However, this requires replacing the piezoelectric substrate and cannot control the electromechanical coupling coefficient of resonators at specific locations. Alternatively, the fabrication process of the SAW device can be adjusted, such as multiple coating or etching processes, to control the electromechanical coupling coefficient of all or specific resonators in the SAW device. However, adjusting the process design parameters of the SAW device requires additional process difficulty and cost. Another common method is to connect a capacitor in parallel to a specific resonator in the design of the SAW device to reduce the electromechanical coupling coefficient and improve the rectangularity. However, the use of parallel capacitors will waste the area of ​​the SAW device.

[0004] Therefore, controlling the electromechanical coupling coefficient of surface acoustic wave devices without replacing the piezoelectric substrate, without increasing the difficulty and cost of the process, and without wasting device area has become an urgent problem to be solved. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide a resonator, filter and RF front-end module, which aims to effectively control the electromechanical coupling coefficient value of the resonator and improve the performance of the resonator.

[0006] To address the aforementioned technical problems, in a first aspect, embodiments of this application provide a resonator, including a piezoelectric substrate and an interdigital transducer disposed on the piezoelectric substrate, wherein the interdigital transducer includes:

[0007] Busbars, at least two of the busbars are disposed on the piezoelectric substrate along a first direction, and the busbars are electrically connected to a plurality of electrode fingers respectively. In the first direction, one end of each electrode finger is connected to one of the two adjacent busbars, and the other end of each electrode finger is spaced apart from the other of the two adjacent busbars.

[0008] The electrodes between two adjacent busbars are arranged alternately and at intervals in the second direction to form a crossover area and a gap area. In the first direction, the gap area is located between the crossover area and the busbar. The first direction and the second direction intersect.

[0009] The electrode refers to a main body and a connector located between the main body and the busbar. The main body is located in the intersection area, and the connector is located in the gap area and connected to one of the busbars.

[0010] The main body includes multiple main body parts. In the same electrode finger, the multiple main body parts are connected sequentially along the first direction, and the included angle between two adjacent main body parts is an obtuse angle.

[0011] Secondly, embodiments of this application also provide a filter, including the resonator described above.

[0012] Thirdly, embodiments of this application also provide a radio frequency front-end module, including the resonator described above.

[0013] The resonator provided in this application has the following beneficial effects:

[0014] This application embodiment, by setting the electrode finger main body in the interdigital transducer to include multiple main body parts, the multiple main body parts are connected sequentially in a first direction, and the included angle between two adjacent main body parts is an obtuse angle. Thus, without replacing the piezoelectric substrate, without increasing the process difficulty and cost, and without wasting device area, the angle between the electrode finger and the piezoelectric substrate in the interdigital transducer can be changed, so as to effectively control the value of the electromechanical coupling coefficient of the resonator, better adapt to the design requirements of surface acoustic wave filter, reduce the manufacturing difficulty and cost, and make the right side of the resonator passband have a steeper rectangularity, thereby optimizing the bandwidth of the resonator and improving the performance of the resonator. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the first structure of the interdigital transducer in the resonator provided in the embodiments of this application;

[0017] Figure 2 This is a schematic diagram of the second structure of the interdigital transducer in the resonator provided in the embodiments of this application;

[0018] Figure 3 This is a schematic diagram of the third structure of the interdigital transducer in the resonator provided in the embodiments of this application;

[0019] Figure 4 This is a schematic diagram of the fourth structure of the interdigital transducer in the resonator provided in the embodiments of this application;

[0020] Figure 5 This is a schematic diagram of the fifth structure of the interdigital transducer in the resonator provided in the embodiments of this application;

[0021] Figure 6 This is a schematic diagram of the sixth structure of the interdigital transducer in the resonator provided in the embodiments of this application;

[0022] Figure 7 This is a schematic diagram of the structure of the interdigital transducer in the resonator of the comparative example provided in the embodiments of this application;

[0023] Figure 8 These are the admittance curves of the resonators of Embodiment 1 and the comparative example provided in this application. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0026] It should also be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or may be connected to an intermediary component. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component through an intermediary component.

[0027] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0028] In some related technologies, the bandwidth of surface acoustic wave (SAW) devices is adjusted by replacing piezoelectric substrates of different types and orientations. In other related technologies, the bandwidth of SAW devices is adjusted by connecting capacitors in parallel with specific resonators or by adjusting the fabrication process of the SAW device. Here, a specific resonator can be understood as a resonator located at a specific position, or a resonator with specific requirements or applications. For example, connecting a capacitor in parallel with a resonator (connected in series between the input and output terminals) reduces the electromechanical coupling coefficient of the resonator, bringing the anti-resonance point (FA) closer to the resonant point (FR). Similarly, in filters that include series-arm and parallel-arm resonators, connecting a capacitor in parallel with the series-arm resonator reduces the electromechanical coupling coefficient of the series-arm resonator with the capacitor in parallel, resulting in a steeper rectangularity on the right side of the filter's passband. However, connecting the capacitor in parallel results in a significant waste of the SAW device's area. For example, adjusting the filter's process design parameters can be achieved by using multiple coating or etching processes to control the electromechanical coupling coefficient of all or specific resonators in the filter. However, this requires additional process steps on top of the original process, resulting in more process steps and a more complex overall filter manufacturing process, which in turn increases the process difficulty and cost.

[0029] Therefore, as Figure 1 As shown, this application provides a resonator, filter, and RF front-end module. In the interdigital transducer 100, the main body 21 of the electrode finger 20 includes multiple main body parts 211. The multiple main body parts 211 are connected sequentially in the arrangement direction of the bus bar 10, and the included angle between two adjacent main body parts 211 is an obtuse angle. This makes the part of the electrode finger 20 located in the cross region C form a bent structure. In this way, the electromechanical coupling coefficient of the resonator can be controlled and the bandwidth of the resonator can be optimized without replacing the piezoelectric substrate, without increasing the process difficulty and cost, and without wasting device area.

[0030] The following is in conjunction with Appendix 1 to Figure 8 This application provides a detailed description of some embodiments. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0031] It should be noted that in the attached diagram, Figures 1 to 6 For illustrative purposes only, where, Figures 1 to 6 Each example illustrates a schematic diagram of one structure of the interdigital transducer 100 of the resonator in this embodiment. Figure 7 This is a schematic diagram of the interdigital transducer 100 of the resonator in the comparative example. Figure 8 Exemplary examples show the admittance curves of resonators with two angle designs in Embodiment 1, as well as the admittance curves of resonators in comparative examples. These figures do not limit the construction of the interdigital transducer 100 of the resonator in this embodiment, and the figures can be combined with each other without conflict.

[0032] like Figure 1 and Figure 2 As shown, the resonator provided in this application embodiment includes a piezoelectric substrate (not shown) and an interdigital transducer 100 disposed on the piezoelectric substrate. The interdigital transducer 100 includes at least two busbars 10, which are spaced apart on the piezoelectric substrate along a first direction. Each busbar 10 is electrically connected to a plurality of electrode fingers 20. In the first direction, one end of each electrode finger 20 is connected to one of two adjacent busbars 10, and the other end of each electrode finger 20 is spaced apart from the other of the two adjacent busbars 10. In the following embodiments, two busbars 10 spaced apart in the first direction are used as an example for description; other arrangements or types of busbars 10 are within the scope of protection of this application.

[0033] Furthermore, the electrode fingers 20 between two adjacent busbars 10 are arranged alternately and at intervals in the second direction to form a crossover area C and a gap area G. In the first direction, the gap area G is located between the crossover area C and the busbar 10. It can be understood that there are two gap areas G between the two busbars 10. In the first direction, the two gap areas G are located on opposite sides of the crossover area C, and the first direction and the second direction intersect. The electrode finger 20 includes a main body 21 and a connector 22 located between the main body 21 and the busbar 10. The main body 21 is located in the crossover area C. It should be noted that the crossover area C is the area where two adjacent electrode fingers 20 overlap in the second direction. This area is the main working area of ​​the resonator, which can also be understood as the resonant area. The connector 22 is located in the gap area G and connected to a busbar 10. The main body 21 includes multiple main body parts 211. In the same electrode finger 20, multiple main body parts 211 are connected sequentially along the first direction, and the included angle between two adjacent main body parts 211 is an obtuse angle.

[0034] In this embodiment, the main body 21 of the interdigital transducer 100, which provides electrode fingers 20, includes multiple main body portions 211. These multiple main body portions 211 are connected sequentially in a first direction, and the included angle between two adjacent main body portions 211 (e.g., ...) Figure 1 As shown, θ and β are obtuse angles. Thus, among the multiple main body portions 211 of the same electrode finger 20, a number of main body portions 211 can be arranged to be perpendicular to the busbar 10, while another number of main body portions 211 are not perpendicular to the busbar 10 (i.e., the included angle between the main body portion 211 and the busbar 10 is greater than 0° and less than 90°). Alternatively, each main body portion 211 can be arranged to be not perpendicular to the busbar 10.

[0035] In this way, the bends at the junctions of two adjacent main body portions 211 within the same electrode finger 20 can be bent toward the opposite side (e.g., the left) or the opposite side (e.g., the right), giving the main body portion 21 of the electrode finger 20 at least two bends, forming a multi-pass (at least two bends) bending structure. This eliminates the need to replace the piezoelectric substrate, add a parallel capacitor to the resonator, or use multiple coating or etching processes to control the electromechanical coupling coefficient of the resonator. Consequently, the interdigital transducer 10 can be modified without replacing the piezoelectric substrate, without increasing the process difficulty and cost, and without wasting device area. The angle between electrode finger 20 and the piezoelectric substrate is used to control the electromechanical coupling coefficient (K) value of the resonator (such as a specific resonator), thereby better adapting to the design requirements of surface acoustic wave filters. Furthermore, under the same conditions, i.e., with the same piezoelectric substrate and structural parameters (aperture, pitch, duty cycle, etc.), compared to the case where the portion of electrode finger 20 located in the cross region C is perpendicular to the busbar 10, this embodiment can also effectively reduce the electromechanical coupling coefficient value of the resonator, making the right side of the resonator passband have a steeper rectangularity, thereby optimizing the bandwidth of the resonator and improving its performance.

[0036] In addition, this embodiment reduces the electromechanical coupling coefficient of the resonator without changing the existing process steps or wasting device area, making the right side of the resonator passband have a steeper rectangularity, and reducing the manufacturing difficulty and cost.

[0037] It should be noted that the first direction can be understood as the arrangement direction of the busbar 10, or the front-to-back direction of the interdigital transducer 100 when viewed from above. The second direction can be understood as the left-to-right direction of the interdigital transducer 100 when viewed from above. Furthermore, the specific number of main body sections 211 in the electrode fingers 20 can be set according to actual needs. For example, the main body section 21 of the electrode fingers 20 can have two, three, four, or five bending segments to form a two-pass, three-pass, four-pass, or five-pass bending structure. The included angle between two adjacent main body sections 211 can be adjusted to obtain the target electromechanical coupling coefficient value and the target bandwidth, thereby expanding the applicable scenarios.

[0038] like Figure 2 As shown, in some embodiments, the number of main body portions 211 in the same electrode finger 20 is two, and the included angle between the two main body portions 211 is α1, wherein α1 satisfies: 120°≤α1<180°. As in the embodiments of this application, α1 is set to 120°, 130°, 140°, 150°, 160° or 170°. The above setting can ensure that the two main body portions 211 of the same electrode finger 20 form an obtuse angle, thereby ensuring that the main body 21 forms a two-stage bending structure, thereby changing the angle between the electrode finger 20 and the piezoelectric substrate in the interdigital transducer 100, effectively reducing the electromechanical coupling coefficient (K) value of the resonator.

[0039] It should be noted that in embodiments where there are two main body portions 211 in the same electrode finger 20, the two main body portions 211 can be arranged symmetrically or asymmetrically.

[0040] like Figure 2 As shown, in some embodiments, the number of main body portions 211 in the same electrode finger 20 is two, and the lengths of the two main body portions 211 in the first direction are Ls and Lx, respectively, where 0≤|Ls-Lx|≤0.05um.

[0041] In this embodiment, based on the obtuse angle formed by the two main body portions 211 in the same electrode finger 20, the sizes of Ls and Lx are adjustable. In some embodiments, the lengths of the two main body portions 211 in the first direction are the same, which is convenient for manufacturing. In other embodiments, the lengths of the two main body portions 211 in the first direction are different. For example, in the embodiment of this application, the difference between Ls and Lx is set to 0.01um, 0.02um, 0.03um, 0.04um or 0.045um, which can realize the bending structure of the main body 21, thereby changing the angle between the electrode finger 20 and the piezoelectric substrate in the interdigital transducer 100, effectively reducing the K value of the resonator.

[0042] It should be noted that in embodiments where the number of main body portions 211 in the same electrode finger 20 is two, specific combinations of Ls, Lx and α1 can be selected according to actual needs to meet different usage scenarios, such as usage scenarios requiring narrow transition bands and small K values.

[0043] like Figure 2 As shown, in some embodiments, in the first direction, the number of main body portions 211 in the same electrode finger 20 is two, and the two main body portions 211 are relative to the centerline of the main body member 21 (e.g., Figure 2 As shown in i), the main body 21 is symmetrically arranged with its centerline parallel to the length direction of the busbar 10 (this direction can be understood as the second direction). The straight-line distance between the centerline of the main body 21 and one of the two adjacent busbars 10 is D1, and the straight-line distance between the centerline of the main body 21 and the other of the two adjacent busbars 10 is D2, where D1 = D2.

[0044] In this embodiment, based on the obtuse angle formed between the two main body parts 211 in the same electrode finger 20, the two main body parts 211 are set to be symmetrical with respect to the center line of the main body 21. This not only enables the main body 21 to form a bent structure, but also helps to reduce the manufacturing difficulty.

[0045] It is understood that in an embodiment where there are two main body parts 211 in the same electrode finger 20, the cross region C includes a middle region Ca and two edge regions Cb. The two edge regions Cb are located on both sides of the middle region Ca in the first direction, and the main body 21 is located in the middle region Ca, so that the position of the main body 21 is centered in the first direction, reducing the manufacturing difficulty.

[0046] like Figure 3 and Figure 5 As shown, in some embodiments, the number of main body portions 211 in the same electrode finger 20 is at least three, and the included angle between two adjacent main body portions 211 ranges from 120° to 180°. For example, in the embodiments of this application, the included angle between two adjacent main body portions 211 is 125°, 135°, 145°, 155°, 165°, or 175°. The above arrangement can ensure that an obtuse angle is formed between two adjacent main body portions 211 of the same electrode finger 20, thereby ensuring that the main body 21 forms a bent structure with at least two bent segments, thereby changing the angle between the electrode finger 20 and the piezoelectric substrate in the interdigital transducer 100, and effectively controlling the electromechanical coupling coefficient (K) value of the resonator.

[0047] like Figure 3 and Figure 4As shown, in some embodiments, in the same electrode finger 20, multiple main body portions 211 include a first main body portion 211a, a second main body portion 211b, and a third main body portion 211c, which are connected sequentially along a first direction; the intersection region C includes a first region C1, a second region C2, and a third region C3, in which the first region C1 and the third region C3 are located on opposite sides of the second region C2 in the first direction; the first main body portion 211a is located in the first region C1, the second main body portion 211b is located in the second region C2, and the third main body portion 211c is located in the third region C3; the straight-line distance between the side of the first region C1 away from the second region C2 and one of the two adjacent busbars 10 is D3, and the straight-line distance between the side of the third region C3 away from the second region C2 and the other of the two adjacent busbars 10 is D4, where D3 = D4.

[0048] In this embodiment, based on the obtuse angle formed between two adjacent main body parts 211, the number of main body parts 211 in the same electrode finger 20 can be three. The three main body parts 211 are respectively located in the first region C1, the second region C2 and the third region C3 of the intersection region C, and the region formed by the first region C1, the second region C2 and the third region C3 is centrally located in the intersection region C. Thus, the main body 21 is centrally located between two adjacent busbars 10, thereby reducing the manufacturing difficulty while realizing the bending structure of the main body 21.

[0049] It is understood that in an embodiment where the number of main body parts 211 in the same electrode finger 20 is three, the cross region C includes a middle region Ca and two edge regions Cb. The two edge regions Cb are located on both sides of the middle region Ca in the first direction, and the main body 21 is located in the middle region Ca, so that the position of the main body 21 is centered in the first direction, reducing the manufacturing difficulty.

[0050] like Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments, the included angle between the second main body 211b and the busbar 10 is α2 (e.g., Figure 3 and Figure 4In the first embodiment, the angle between the extended frame line s of the second main body 211b in the first direction and the busbar 10 is α2, where α2 satisfies: 0° < α2 ≤ 90°. In this embodiment, α2 is set to 35°, 55°, 75°, or 90° to achieve the second main body 211b being perpendicular to or inclined relative to the busbar 10. Further, in the same electrode finger 20, the angle between the first main body 211a and the second main body 211b is θ, and the angle between the second main body 211b and the third main body 211c is β, where θ = β, and / or, the value of θ ranges from 150° to 180°, and / or, the value of β ranges from 150° to 180°.

[0051] In this embodiment, θ and β are equal, which helps to keep the K values ​​of the first region C1, the second region C2, and the third region C3 the same, reducing the introduction of stray modes and improving the performance of the resonator. Furthermore, compared to related technologies where the portion of the electrode finger 20 located in the crossover region C is tilted relative to the busbar 10, and where the plane occupied by the portion of the electrode finger 20 in the crossover region C is a parallelogram with interior angles not at 90 degrees, this embodiment sets θ and β to be equal, making the plane occupied by the portion of each electrode finger 20 in the crossover region C rectangular rather than a parallelogram. Therefore, this embodiment also improves the rectangularity of the resonator.

[0052] In this embodiment, based on the range of values ​​for θ and β, θ can be set to 150°, 160°, 170° or 180°, and β can be set to 150°, 160°, 165° or 175°. This achieves an obtuse angle between the first main body portion 211a and the second main body portion 211b in the same electrode finger 20, and an obtuse angle between the second main body portion 211b and the third main body portion 211c. As a result, the main body 21 forms a bent structure, thereby changing the angle between the electrode finger 20 and the piezoelectric substrate in the interdigital transducer 100, and effectively controlling the electromechanical coupling coefficient (K) value of the resonator.

[0053] Furthermore, both increasing and decreasing θ and β within the range of 150° to 180° can effectively control the K value of the resonator.

[0054] like Figure 3 and Figure 4As shown, in some embodiments, in the same electrode finger 20, the included angle between the first main body portion 211a and the second main body portion 211b is θ, and the included angle between the second main body portion 211b and the third main body portion 211c is β; wherein, the value of θ ranges from 155° to 175°, as in the embodiments of this application, the value of θ is 155°, 160°, 166°, 173° or 175°, and / or, the value of β ranges from 155° to 175°, as in the embodiments of this application, the value of θ is 155°, 160°, 166°, 173° or 175°. The preferred settings of θ and β above can realize that the included angle between the first main body portion 211a and the second main body portion 211b in the same electrode finger 20 is an obtuse angle, and the included angle between the second main body portion 211b and the third main body portion 211c is an obtuse angle, realizing that the main body member 21 forms a bent structure.

[0055] like Figure 3 and Figure 4 As shown, in some embodiments, in the same electrode finger 20, the included angle between the first main body portion 211a and the second main body portion 211b is θ, and the included angle between the second main body portion 211b and the third main body portion 211c is β, wherein 0°≤|θ-β|≤7°, and as in the embodiments of this application, the difference between θ and β is 1°, 2°, 3°, 4°, 5° or 6°. Preferably, 0°≤|θ-β|≤2°, and as in the embodiments of this application, the difference between θ and β is 0.5°, 1°, 1.5° or 1.9°.

[0056] In this embodiment, the number of main body portions 211 in the same electrode finger 20 is at least three, and both θ and β can be within the range of 120° to 180°. θ and β can be equal or unequal. The above-mentioned design of the difference between θ and β can achieve an obtuse angle between the first main body portion 211a and the second main body portion 211b in the same electrode finger 20, and an obtuse angle between the second main body portion 211b and the third main body portion 211c, thereby realizing the bending structure of the main body member 21. In addition, controlling the difference between θ and β within the above-mentioned range can reduce the difference in K values ​​between any two of the first region C1, the second region C2, and the third region C3.

[0057] like Figure 3 and Figure 4 As shown, in some embodiments, the length of the first main body portion 211a in the first direction is L1, the length of the second main body portion b in the first direction is L2, and the length of the third main body portion 211c in the first direction is L3; wherein, L1 > L2, and L3 > L2.

[0058] In this embodiment, based on the obtuse angles formed between the first main body 211a and the second main body 211b, and between the second main body 211b and the third main body 211c, the lengths of the first main body 211a and the third main body 211c are both greater than the length of the second main body 211b in the busbar 10 arrangement direction, which can effectively control the K value of the resonator.

[0059] Furthermore, the length of the intersection area C in the first direction is L, the second main body 211b is perpendicular to the busbar 10, and the length L2 of the second main body 211b in the first direction is less than L / 3. In this embodiment, reducing L2 and increasing L1 and / or L3 can increase the influence of the main body 21 on the K value, thereby reducing L2 and increasing L1 and / or L3 can help control the K value.

[0060] It should be noted that in embodiments where the number of main body portions 211 in the same electrode finger 20 is three, specific combinations of L1, L3 and θ can be selected according to actual needs, and / or specific combinations of L2, L3 and β can be selected to meet different usage scenarios, such as usage scenarios requiring narrow transition bands and small K values.

[0061] like Figure 3 and Figure 4 As shown, in some embodiments, in the same electrode finger 20, based on the obtuse angle between the first main body portion 211a and the second main body portion 211b, and the obtuse angle between the second main body portion 211b and the third main body portion 211c, the second main body portion 211b is perpendicular to the busbar 10, and in the second direction, the width of the first main body portion 211a and the width of the third main body portion 211c are both greater than the width of the second main body portion 211b, which is beneficial for controlling the K value.

[0062] like Figure 3 and Figure 4 As shown, in some embodiments, in the first direction, the first main body portion 211a and the third main body portion 211c are symmetrical about the axis of symmetry of the second main body portion 211b (e.g., ...). Figure 4 As shown in x), the second main body 211b is symmetrically arranged, with its axis of symmetry parallel to the length direction of the busbar 10 (this direction can be understood as the second direction). The straight-line distance between the axis of symmetry of the second main body 211b and one of the two adjacent busbars 10 is D5, and the straight-line distance between the axis of symmetry of the second main body 211b and the other of the two adjacent busbars 10 is D6, where D5 = D6.

[0063] In this embodiment, the first main body 211a and the third main body 211c are symmetrical with respect to the axis of symmetry of the second main body 211b. This not only enables the main body 21 to form a bent structure, but also helps to reduce the manufacturing difficulty.

[0064] like Figure 5 As shown, in some embodiments, in the same electrode finger 20, a plurality of main body portions 211 include a first main body portion 211a, a second main body portion 211b, a third main body portion 211c and a fourth main body portion 211d, and the first main body portion 211a, the second main body portion 211b, the third main body portion 211c and the fourth main body portion 211d are connected sequentially along a first direction. Furthermore, the intersection area C includes a first region C1, a second region C2, a third region C3, and a fourth region C4 arranged sequentially along the first direction. The first main body 211a is located in the first region C1, the second main body 211b is located in the second region C2, the third main body 211c is located in the third region C3, and the fourth main body 211d is located in the fourth region C4. The straight-line distance between the side of the first region C1 away from the second region C2 and one of the two adjacent busbars 10 is D7, and the straight-line distance between the side of the fourth region C4 away from the third region C3 and the other of the two adjacent busbars 10 is D8, where D7 = D8.

[0065] In this embodiment, the number of main body portions 211 in the same electrode finger 20 can be four. Based on the obtuse angle formed between two adjacent main body portions 211, the four main body portions 211 are respectively located in the first region C1, the second region C2, the third region C3, and the fourth region C4 of the intersection area C. The area formed by the first region C1, the second region C2, the third region C3, and the fourth region C4 is centrally located in the intersection area C. Thus, the main body 21 is centrally located between two adjacent busbars 10. In addition to realizing the bending structure of the main body 21, the manufacturing difficulty can also be reduced.

[0066] It is understood that in an embodiment where the number of main body parts 211 in the same electrode finger 20 is four, the cross region C includes a middle region Ca and two edge regions Cb. The two edge regions Cb are located on both sides of the middle region Ca in the first direction, and the main body 21 is located in the middle region Ca, so that the position of the main body 21 is centered in the first direction, reducing the manufacturing difficulty.

[0067] For example, in the same electrode finger 20, the first main body portion 211a and the second main body portion 211b form a first opening 30, the second main body portion 211b and the third main body portion 211c form a second opening 40, and the third main body portion 211c and the fourth main body portion 211d form a third opening 50. In the second direction, the first opening 30 and the third opening 50 are located on one side of the same electrode finger 20, and the second opening 40 is located on the other side of the same electrode finger 20, so that the main body 21 forms a bent structure with four bent segments.

[0068] like Figure 5As shown, in some embodiments, in the same electrode finger 20, the included angle between the first main body portion 211a and the second main body portion 211b is θ, the included angle between the second main body portion 211b and the third main body portion 211c is β, and the included angle between the third main body portion 211c and the fourth main body portion 211d is γ, where θ = β = γ.

[0069] In this embodiment, θ, β, and γ are equal, which keeps the K values ​​of the first region C1, the second region C2, the third region C3, and the fourth region C4 the same, reducing the introduction of stray modes and improving the performance of the resonator. Furthermore, the lengths of the first main body portion 211a, the second main body portion 211b, the third main body portion 211c, and the fourth main body portion 211d in the first direction are all equal. This helps to keep the K values ​​of the first region C1, the second region C2, the third region C3, and the fourth region C4 the same, reducing the introduction of stray modes, improving the performance of the resonator, and also reducing the manufacturing difficulty.

[0070] Furthermore, compared to the related technologies in which the portion of the electrode finger 20 located in the crossover area C is tilted relative to the busbar 10, the planar area occupied by the portion of the electrode finger 20 located in the crossover area C in the related technologies is a parallelogram with interior angles not 90 degrees. In this embodiment, θ, β and γ are set to be equal, so that the planar area occupied by the portion of each electrode finger 20 located in the crossover area C is a rectangle instead of a parallelogram. Thus, this embodiment can also improve the rectangularity of the resonator.

[0071] like Figure 5As shown, in some embodiments, in the same electrode finger 20, the included angle between the first main body portion 211a and the second main body portion 211b is θ, the included angle between the second main body portion 211b and the third main body portion 211c is β, and the included angle between the third main body portion 211c and the fourth main body portion 211d is γ, wherein 0°≤|θ-β|≤7°, 0°≤|θ-γ|≤7°, and 0°≤|γ-β|≤7°. As in the embodiments of this application, the difference between θ and β is 0.5°, 1.5°, 2.5°, 3.5°, 4.5°, 5.5°, or 6.5°, the difference between θ and γ is 0.5°, 1.5°, 2.5°, 3.5°, 4.5°, 5.5°, or 6.5°, and the difference between γ and β is 0.5°, 1.5°, 2.5°, 3.5°, 4.5°, 5.5°, or 6.5°. Preferably, 0°≤|θ-β|≤2°, 0°≤|θ-γ|≤2°, 0°≤|γ-β|≤2°. As in the embodiments of this application, the difference between θ and β is 0.4°, 0.8°, 1.2°, 1.6° or 1.8°. As in the embodiments of this application, the difference between θ and γ is 0.4°, 0.8°, 1.2°, 1.6° or 1.8°. As in the embodiments of this application, the difference between γ and β is 0.4°, 0.8°, 1.2°, 1.6° or 1.8°.

[0072] In this embodiment, the number of main body portions 211 can be four, and θ, β, and γ can all take values ​​within the range of 120° to 180°. θ, β, and γ can be equal, or at least two of θ, β, and γ can be unequal. The above-mentioned design of the differences in θ, β, and γ can achieve an obtuse angle between the first main body portion 211a and the second main body portion 211b in the same electrode finger 20, an obtuse angle between the second main body portion 211b and the third main body portion 211c, and an obtuse angle between the third main body portion 211c and the fourth main body portion 211d, thereby facilitating the formation of a bent structure in the main body member 21. In addition, controlling the differences between θ and β, θ and γ, and γ and β within the above-mentioned range can reduce the difference in K values ​​between any two of the first region C1, the second region C2, the third region C3, and the fourth region C4.

[0073] It should be noted that in embodiments where the number of main body portions 211 in the same electrode finger 20 is four, specific combinations of θ, β, and γ can be selected according to actual needs to meet different application scenarios, such as those requiring a narrow transition band and a small K value. Furthermore, the length of each main body portion 211 can be adjusted to adapt to more application scenarios.

[0074] like Figure 3As shown, in some embodiments, the electrode finger 20 further includes a first extension 23 and a second extension 24. One end of the first extension 23 is connected to the connector 22, and the other end of the first extension 23 is connected to the main body 21. The second extension 24 is connected to the end of the main body 21 away from the connector 22.

[0075] In this embodiment, the main body 21 is electrically connected to the connector 22 through the first extension 23. Among the electrode fingers 20 between two adjacent busbars 10, the first extension 23 is spaced apart from one of the busbars 10, and the second extension 24 is spaced apart from the other busbar 10, so as to form a gap region G between the first extension 23 and one of the busbars 10, and to form another gap region G between the first extension 23 and the other busbar 10.

[0076] Furthermore, the intersection area C includes a middle area Ca and two edge areas Cb. In the first direction, the two edge areas Cb are located on both sides of the middle area Ca, the first extension 23 is located in one edge area Cb, the second extension 24 is located in the other edge area Cb, and the main body 21 is located in the middle area Ca, so that the main body 21 is centered in the first direction.

[0077] Furthermore, in the first direction, the length of the first extension 23 can be equal to the length of the second extension 24, or the length of the first extension 23 can be different from the length of the second extension 24. Meanwhile, the first extension 23 is perpendicular to the busbar 10 and the second extension 24 is perpendicular to the busbar 10. By making the above-described special arrangement at the end of the main body 21, the sound velocity is improved and the K value of the resonator is improved.

[0078] like Figure 3 As shown, in some embodiments, both the first extension 23 and the second extension 24 are perpendicular to the busbar 10. By making the above-described arrangement at the end of the main body 21, the sound velocity is improved and the K value of the resonator is improved.

[0079] like Figure 3 and Figure 4 As shown, in some embodiments, both the first extension 23 and the second extension 24 are provided with a mass load structure 25. In this embodiment, the mass load structure 25 is disposed in the portion of the electrode finger 20 located in the edge region Cb, which can make the sound speed in the middle region Ca greater than the sound speed in the edge region Cb, thereby making the propagation speed of the sound wave in the edge region Cb less than the propagation speed in the middle region Ca, and thus improving the suppression of the transverse modes of the resonator based on controlling the K value.

[0080] For example, the mass load structure 25 may be a thickening of the electrode fingers 20 in the edge region Cb to form a spike thickening structure, or a thickening of the electrode fingers 20 in the edge region Cb to form a Hammer widening structure, in order to reduce the sound velocity in the edge region Cb.

[0081] For example, the busbar 10 and electrode finger 20 can be made of metals such as aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, and tungsten. No specific limitation is made here, and the choice can be made according to the specific situation. However, the selected materials need to have good conductivity.

[0082] like Figure 2 As shown, in some embodiments, the included angle between the connector 22 and the busbar 10 is α3, where α3 satisfies: 0° < α3 ≤ 90°. For example, in the embodiments of this application, α3 is set to 30°, 35°, 45°, 55°, 65°, 75°, or 90°. In this embodiment, the connector 22 located in the gap region G is perpendicular to the busbar 10, or the connector 22 is inclined relative to the busbar 10, which allows the interdigital transducer 100 to adapt to different application scenarios.

[0083] like Figure 1 As shown, in some embodiments, in the same electrode finger 20, each main body portion 211 has the same length in the first direction, thereby dividing the main body 21 into multiple equal parts, which is beneficial to keeping the K value the same in each bending sub-region in the intersection area C. Each of the multiple main body portions 211 corresponds one-to-one with a multiple bending sub-region.

[0084] like Figure 1 As shown, in some embodiments, the main body 211 of the same electrode finger 20 is preferably set to an odd number, such as three, five or seven, so that in the second direction, the number of openings of the electrode finger 20 in one direction (such as the left side) is the same as the number of openings in the other direction (such as the right side). In this way, by controlling the number and orientation of the openings in the multiple electrode fingers, the same electrode finger has the same effect on the sound velocity on both the left and right sides, thereby further ensuring the influence of the electrode finger 20 on the sound velocity due to its structure or arrangement.

[0085] like Figure 1 As shown, in some embodiments, the width of each electrode finger 20 is the same in the second direction, which helps to reduce the manufacturing difficulty.

[0086] like Figure 6As shown, in some embodiments, the interdigital transducer 100 further includes a plurality of electrode pseudo-fingers 60, which correspond one-to-one with the electrode fingers 20. The electrode pseudo-fingers 60 are spaced apart from the electrode fingers 20 in a first direction. The electrode pseudo-fingers 60 are located in the gap region G and connected to the busbar 10. By setting the electrode pseudo-fingers 60, the Q value of the resonator can be improved, energy leakage can be reduced, and the heterodyne suppression effect of the gap region G can be further improved.

[0087] like Figure 6 As shown, in some embodiments, in the second direction, the width of the electrode dummy finger 60 is the same as the width of the electrode finger 20, which helps to reduce the manufacturing difficulty and also helps to ensure the consistency of the electrode pattern.

[0088] like Figure 6 As shown, in some embodiments, in the second direction, the distance between the centerlines of two adjacent electrode fingers 20 is P1, and the distance between the centerlines of two adjacent electrode dummy fingers 60 is P2, where P2 / P1 = 2. It can be understood that the distance between the centerlines of two adjacent electrode fingers 20 connected to the same busbar 10 is P3, and the distance between two adjacent electrode dummy fingers 60 connected to the same busbar 10 is P2, where P3 = P2. This design helps reduce manufacturing difficulty and also helps ensure the consistency of the electrode patterns.

[0089] Combination Figure 1 In some embodiments, the piezoelectric substrate includes a piezoelectric layer and a substrate, with the interdigital transducer 100 disposed on the piezoelectric layer, which covers the substrate. In this embodiment, the piezoelectric substrate can be a single-layer structure or a multi-layer structure, with the substrate supporting the piezoelectric layer and the interdigital transducer 100. The material of the exemplary substrate may include single-crystal materials such as silicon and silicon carbide, and is not specifically limited herein.

[0090] Combination Figure 1 This application also provides a filter that includes the resonator from any of the above embodiments. Because the filter in this embodiment uses the resonator from any of the above embodiments, it can effectively control the electromechanical coupling coefficient value of the filter without replacing the piezoelectric substrate, without increasing the process difficulty and cost, and without wasting device area. This results in a steeper rectangularity on the right side of the filter's passband, thereby optimizing the filter's bandwidth and improving its performance.

[0091] Combination Figure 1This application also provides a radio frequency (RF) front-end module, which includes the resonator in any of the above embodiments. Because the RF front-end module of this embodiment uses the resonator in any of the above embodiments, it can effectively control the electromechanical coupling coefficient of the resonator without replacing the piezoelectric substrate, without increasing process difficulty and cost, and without wasting device area. This optimizes the bandwidth of the resonator and improves its performance, thereby enhancing the performance of the module.

[0092] Based on the resonator provided in the above embodiments, this embodiment also provides Embodiment 1 and a comparative example, and compares Embodiment 1 with the comparative example to make the effects of the embodiments of this application more intuitive. The structure of Embodiment 1 can be referred to... Figure 3 and Figure 4 .

[0093] like Figure 3 , Figure 4 and Figure 7 As shown, in the comparative example and Example 1, the piezoelectric substrate is the same, and the structural parameters (aperture, pitch, duty cycle, etc.) of the interdigital transducer 100 are the same. In the comparative example, the interdigital transducer 100 has a conventional interdigital transducer structure. That is, the comparative example interdigital transducer 100 includes two busbars 10 arranged along a first direction. Each busbar 10 is electrically connected to a plurality of electrode fingers 20. Each electrode finger 20 is connected to one busbar 10 and spaced apart from the other busbar 10. The electrode fingers 20 between the two busbars 10 are arranged alternately and at intervals in the second direction to form a crossover area C and a gap area G. In the first direction, the gap area G is located between the crossover area C and the busbar 10. The first direction and the second direction intersect. Each electrode finger 20 is arranged perpendicular to the busbar 10. It can be understood that when the main body 21 of the electrode finger 20 is divided into a first main body part 211a, a second main body part 211b and a third main body part 211c, θ=β=180°.

[0094] Furthermore, in Embodiment 1, the structure of the electrode finger 20 is optimized based on the comparative example. Specifically, the electrode finger 20 includes a main body 21 and a connector 22 located between the main body 21 and the busbar 10. The main body 21 is located in the intersection area C, and the connector 22 is located in the gap area G and connected to a busbar 10. The main body 21 includes a first main body portion 211a, a second main body portion 211b, and a third main body portion 211c. The first main body portion 211a, the second main body portion 211b, and the third main body portion 211c are connected sequentially along a first direction. The included angle between the first main body portion 211a and the second main body portion 211b is θ, and the included angle between the second main body portion 211b and the third main body portion 211c is β. In this case, one angle of included angles θ and β is set to θ = β = 165°, and the other angle of included angles θ and β is set to θ = β = 173°.

[0095] Figure 8 These are the admittance curves of the resonators in Example 1 and the comparative example.

[0096] like Figure 8 As shown in the figure, the dashed line represents the admittance curve of the resonator with θ and β both at 165° in Example 1, the dotted line represents the admittance curve of the resonator with θ and β both at 173° in Example 1, and the solid line represents the admittance curve of the comparative example. The horizontal axis represents frequency in Hz, and the vertical axis represents admittance in dB. It can be seen from the figure that the resonant points of the dashed, dotted, and solid lines have the same horizontal axis. Furthermore, relative to the solid line, the anti-resonant points of the dashed and dotted lines are shifted to the left. Therefore, the lateral distance between the resonant and anti-resonant points of the dashed and dotted lines is smaller than that of the solid line. Consequently, the K values ​​of the two angle designs in Example 1 are smaller than the K value of the comparative example. Thus, this embodiment can reduce the electromechanical coupling coefficient (K) value of the resonator.

[0097] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the content of this application's specification and drawings under the concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A resonator, characterized in that, The device includes a piezoelectric substrate and an interdigital transducer disposed on the piezoelectric substrate, wherein the interdigital transducer includes: Busbars, at least two of the busbars are disposed on the piezoelectric substrate along a first direction, and the busbars are electrically connected to a plurality of electrode fingers respectively. In the first direction, one end of each electrode finger is connected to one of the two adjacent busbars, and the other end of each electrode finger is spaced apart from the other of the two adjacent busbars. The electrodes between two adjacent busbars are arranged alternately and at intervals in the second direction to form a crossover area and a gap area. In the first direction, the gap area is located between the crossover area and the busbar. The first direction and the second direction intersect. The electrode refers to a main body and a connector located between the main body and the busbar. The main body is located in the intersection area, and the connector is located in the gap area and connected to one of the busbars. The main body includes multiple main body parts. In the same electrode finger, the multiple main body parts are connected sequentially along the first direction, and the included angle between two adjacent main body parts is an obtuse angle.

2. The resonator as described in claim 1, characterized in that, In the same electrode finger, there are two main body parts, and the included angle between the two main body parts is α1, wherein α1 satisfies: 120°≤α1<180°.

3. The resonator as described in claim 2, characterized in that, In the same electrode finger, the lengths of the two main body portions in the first direction are Ls and Lx, respectively, where 0≤|Ls-Lx|≤0.05um; or, In the first direction, in the same electrode finger, two main body portions are symmetrically arranged with respect to the centerline of the main body member. The centerline of the main body member is parallel to the length direction of the busbar. The straight-line distance between the centerline of the main body member and one of the two adjacent busbars is D1, and the straight-line distance between the centerline of the main body member and the other of the two adjacent busbars is D2, where D1 = D2.

4. The resonator as described in claim 1, characterized in that, In the same electrode finger, the number of main body parts is at least three, and the included angle between two adjacent main body parts is in the range of 120° to 180°.

5. The resonator as described in claim 4, characterized in that, In the same electrode finger, the plurality of main body portions include a first main body portion, a second main body portion, and a third main body portion, wherein the first main body portion, the second main body portion, and the third main body portion are connected sequentially along the first direction; The intersection area includes a first region, a second region, and a third region. In the first direction, the first region and the third region are located on opposite sides of the second region. The first main body is located in the first region, the second main body is located in the second region, and the third main body is located in the third region. The straight-line distance between the side of the first region away from the second region and one of the two adjacent busbars is D3, and the straight-line distance between the side of the third region away from the second region and the other of the two adjacent busbars is D4, where D3 = D4.

6. The resonator as described in claim 5, characterized in that, The included angle between the second main body and the busbar is α2, wherein α2 satisfies: 0°<α2≤90°; In the same electrode finger, the included angle between the first main body and the second main body is θ, and the included angle between the second main body and the third main body is β, wherein θ = β, and / or, the value of θ ranges from 150° to 180°, and / or, the value of β ranges from 150° to 180°.

7. The resonator as described in claim 5, characterized in that, In the same electrode finger, the included angle between the first main body portion and the second main body portion is θ, and the included angle between the second main body portion and the third main body portion is β; Wherein, the value of θ ranges from 155° to 175°, and / or, the value of β ranges from 155° to 175°.

8. The resonator as described in claim 5, characterized in that, In the same electrode finger, the included angle between the first main body and the second main body is θ, and the included angle between the second main body and the third main body is β, wherein 0°≤|θ-β|≤7°.

9. The resonator as claimed in claim 8, characterized in that, 0°≤|θ-β|≤2°.

10. The resonator as claimed in claim 5, characterized in that, The length of the first main body portion in the first direction is L1, the length of the second main body portion in the first direction is L2, and the length of the third main body portion in the first direction is L3; wherein, L1 > L2 and L3 > L2.

11. The resonator as claimed in claim 5, characterized in that, The second main body is perpendicular to the busbar, and in the second direction, the width of the first main body and the width of the third main body are both greater than the width of the second main body; and / or, In the first direction, the first main body and the third main body are symmetrically arranged with respect to the axis of symmetry of the second main body. The axis of symmetry of the second main body is parallel to the length direction of the busbar. The straight-line distance between the axis of symmetry of the second main body and one of the two adjacent busbars is D5, and the straight-line distance between the axis of symmetry of the second main body and the other of the two adjacent busbars is D6, where D5 = D6.

12. The resonator as claimed in claim 4, characterized in that, In the same electrode finger, the plurality of main body portions include a first main body portion, a second main body portion, a third main body portion, and a fourth main body portion, wherein the first main body portion, the second main body portion, the third main body portion, and the fourth main body portion are connected sequentially along the first direction; The intersection area includes a first region, a second region, a third region, and a fourth region arranged sequentially along the first direction. The first main body is located in the first region, the second main body is located in the second region, the third main body is located in the third region, and the fourth main body is located in the fourth region. The straight-line distance between the side of the first region away from the second region and one of the two adjacent busbars is D7, and the straight-line distance between the side of the fourth region away from the third region and the other of the two adjacent busbars is D8, where D7 = D8.

13. The resonator as claimed in claim 12, characterized in that, In the same electrode finger, the included angle between the first main body portion and the second main body portion is θ, the included angle between the second main body portion and the third main body portion is β, and the included angle between the third main body portion and the fourth main body portion is γ, where θ = β = γ.

14. The resonator as claimed in claim 12, characterized in that, In the same electrode finger, the included angle between the first main body and the second main body is θ, the included angle between the second main body and the third main body is β, and the included angle between the third main body and the fourth main body is γ, wherein 0°≤|θ-β|≤7°, 0°≤|θ-γ|≤7°, and 0°≤|γ-β|≤7°.

15. The resonator as claimed in claim 14, characterized in that, 0°≤|θ-β|≤2°, 0°≤|θ-γ|≤2°, 0°≤|γ-β|≤2°.

16. The resonator according to any one of claims 1-15, characterized in that, The electrode finger further includes a first extension and a second extension. One end of the first extension is connected to the connector, and the other end of the first extension is connected to the main body. The second extension is connected to the end of the main body away from the connector.

17. The resonator as claimed in claim 16, characterized in that, Both the first extension and the second extension are perpendicular to the busbar; and / or, Both the first extension and the second extension are provided with a mass load structure.

18. The resonator according to any one of claims 1-15, characterized in that, The included angle between the connector and the busbar is α3, wherein α3 satisfies: 0°<α3≤90°.

19. The resonator according to any one of claims 1-15, characterized in that, In the same electrode finger, the length of each of the main body portions is the same in the first direction; and / or, Each of the aforementioned electrodes has the same width in the second direction.

20. The resonator according to any one of claims 1-15, characterized in that, The interdigital transducer also includes a plurality of electrode pseudofingers, which correspond one-to-one with the electrode fingers. The electrode pseudofingers are arranged at intervals opposite to the electrode fingers in the first direction. The electrode pseudofingers are located in the gap region and connected to the busbar.

21. The resonator as claimed in claim 20, characterized in that, In the second direction, the width of the electrode dummy finger is the same as the width of the electrode finger; and / or, In the second direction, the distance between the midlines of two adjacent electrode fingers is P1, and the distance between the midlines of two adjacent electrode prosticors is P2, where P2 / P1 = 2.

22. The resonator according to any one of claims 1-15, characterized in that, The piezoelectric substrate includes a piezoelectric layer and a substrate, the interdigital transducer is disposed on the piezoelectric layer, and the piezoelectric layer covers the substrate.

23. A filter, characterized in that, Including the resonator as described in any one of claims 1-22.

24. A radio frequency front-end module, characterized in that, Including the resonator as described in any one of claims 1-22.

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