Interdigital transducer, acoustic resonator and electronic equipment

Abstract

The utility model relates to an interdigital transducer, an acoustic resonator and electronic equipment. The interdigital transducer includes: a first bus bar and a second bus bar; the interdigital electrode comprises a plurality of first electrode fingers and a plurality of second electrode fingers, the first electrode fingers and the second electrode fingers are located between the first bus bar and the second bus bar, and the first electrode fingers and the second electrode fingers are oppositely arranged in the first direction in a one-to-one correspondence mode; an edge area, a spacing area, an inclined area and a central area which are arranged in the first direction are arranged between the first bus bar and the second bus bar, the inclined area is located between the central area and the spacing area, the spacing area is located between the inclined area and the edge area, and the central area is located on the side, away from the spacing area, of the inclined area; the portion, located in the inclined area, of the second electrode finger comprises a first section, a second section and a third section which are sequentially connected in the first direction, and the first section, the second section and the third section are obliquely arranged relative to the first direction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of signal processing, in particular to an interdigital transducer, an acoustic resonator and an electronic device. BACKGROUND

[0002] The surface acoustic wave resonator comprises a piezoelectric substrate and an interdigital transducer, wherein the interdigital transducer is located on one side of the piezoelectric substrate. The interdigital transducer comprises a bus bar and interdigital electrodes. The piezoelectric material in the piezoelectric substrate has a piezoelectric effect, and can realize mutual conversion between an electrical signal and a sound wave. The surface acoustic wave is excited through the interaction between the interdigital electrodes and the piezoelectric material, and the resonant characteristics of the surface acoustic wave can be used to construct the surface acoustic wave resonator.

[0003] With the continuous development of communication technology, higher requirements are put forward for the performance of the resonator, i.e. higher working frequency, higher Q value and larger bandwidth. In addition to energy leakage in the vertical direction, the resonator will also produce certain transverse modes and energy leakage in the horizontal direction of the electrode. The transverse modes appear in the form of stray peaks in the absolute value of the resonator admittance curve, and the frequencies of the transverse modes are generally distributed within the band of the resonator, i.e. between the resonant frequency and the anti-resonant frequency, which will cause the deterioration of the in-band ripple, the in-band flatness and the insertion loss, and seriously affect the performance of the resonator. CONTENT OF THE UTILITY MODEL

[0004] Therefore, it is necessary to provide an interdigital transducer, an acoustic resonator and an electronic device capable of improving the influence of the transverse modes excited in the acoustic resonator.

[0005] An interdigital transducer comprises:

[0006] a first bus bar and a second bus bar, which are spaced apart and arranged oppositely along a first direction; and

[0007] interdigital electrodes comprising a plurality of first electrode fingers and a plurality of second electrode fingers located between the first bus bar and the second bus bar, each of the first electrode fingers and each of the second electrode fingers being arranged oppositely to each other in the first direction; one of the first electrode fingers and the second electrode fingers arranged oppositely to each other in the first direction is connected to the first bus bar, and the other one is connected to the second bus bar.

[0008] The first bus bar and the second bus bar comprise an edge region, a spacing region, an inclined region and a central region arranged along the first direction, the inclined region is located between the central region and the spacing region, the spacing region is located between the inclined region and the edge region, and the central region is located on the side of the inclined region away from the spacing region.

[0009] The first electrode fingers are located in the edge region, the second electrode fingers are located in the edge region, part of the spacing region and part of the center region parallel to the first direction, and the second electrode fingers located in part of the inclined region include a first section, a second section and a third section connected in sequence along the first direction, the first section, the second section and the third section are all arranged obliquely relative to the first direction, and the second section is opposite to the first section and the third section in the direction of inclination relative to the first direction.

[0010] In some embodiments, the part of the second electrode fingers in the center region is a center section, and the two sides of the center section in a second direction perpendicular to the first direction are a first side and a second side, respectively.

[0011] One end of the first section away from the second section is connected to the center section, the first section is inclined relative to the center section to the first side of the center section, the second section is inclined relative to the first section to the second side of the center section, and the third section is inclined relative to the second section to the first side of the center section.

[0012] In some embodiments, the lengths of the first section, the second section and the third section in the first direction are equal.

[0013] In some embodiments, the two side edges of the first section in the second direction are first side edges, the two first side edges are parallel to each other, and the length of the first side edge in the orthogonal projection on a plane perpendicular to the first direction is a, and the length of the first side edge in the orthogonal projection on a plane perpendicular to the second direction is b.

[0014] The two side edges of the second section in the second direction are second side edges, the two second side edges are parallel to each other, and the length of the second side edge in the orthogonal projection on a plane perpendicular to the first direction is 2a, and the length of the second side edge in the orthogonal projection on a plane perpendicular to the second direction is b.

[0015] The two side edges of the third section in the second direction are third side edges, the two third side edges are parallel to each other, and the length of the third side edge in the orthogonal projection on a plane perpendicular to the first direction is a, and the length of the third side edge in the orthogonal projection on a plane perpendicular to the second direction is b.

[0016] In some embodiments, the part of the second electrode fingers in the inclined region includes N inclined units connected in sequence along the first direction, each of the inclined units includes the first section, the second section and the third section connected in sequence along the first direction, and N is a positive integer greater than or equal to 1.

[0017] In some embodiments, N is equal to 1, 2 or 3.

[0018] In some embodiments, when N is equal to 1, 0.1p≤a≤0.15p, 0.3p≤b≤0.5p; wherein p represents the distance between the center lines of two adjacent second electrode fingers.

[0019] When N is equal to 2, 0.1p≤a≤0.15p, 0.3p≤b≤0.35p;

[0020] When N is equal to 3, 0.1p≤a≤0.12p, 0.15p≤b≤0.2p.

[0021] In some embodiments, the edge region comprises a first edge region and a second edge region spaced apart along the first direction, the spacing region comprises a first spacing region and a second spacing region spaced apart along the first direction, and the tilt region comprises a first tilt region and a second tilt region spaced apart along the first direction.

[0022] The first edge region is located between the first bus bar and the first spacing region, the first tilt region is located between the first spacing region and the center region, the second edge region is located between the second bus bar and the second spacing region, and the second tilt region is located between the second spacing region and the center region.

[0023] In some embodiments, in the first edge region and the second edge region, the first electrode fingers and the second electrode fingers are alternately arranged along a second direction, and the second direction is perpendicular to the first direction.

[0024] An acoustic resonator comprising a piezoelectric substrate and an interdigital transducer as in any of the above embodiments, the interdigital transducer being disposed on one side of the piezoelectric substrate.

[0025] An electronic device comprising an acoustic resonator as in any of the above embodiments.

[0026] The aforementioned interdigital transducers, acoustic resonators, and electronic devices, by setting an inclined region, each second electrode finger in the inclined region includes a first segment, a second segment, and a third segment that are sequentially connected and all inclined relative to the first direction. The inclination direction of the second segment is opposite to that of the first and third segments, thereby disrupting the boundary conditions in the direction perpendicular to the main propagation direction of the surface acoustic wave (i.e., the first direction). Since the acoustic impedance of the first, second, and third segments is different from that of the second electrode fingers in other regions, the surface acoustic wave can be reflected, thereby suppressing the excitation of transverse modes and suppressing energy leakage from the transverse edges to the busbar, thus achieving the purpose of improving the Q value. Furthermore, the energy is more concentrated between the interdigital electrodes, resulting in higher mechanical energy to electrical energy conversion efficiency and achieving the purpose of improving the electromechanical coupling coefficient. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of an interdigital transducer in one embodiment of this application;

[0028] Figure 2 for Figure 1 The diagram shows the structure of the interdigital transducer located in the inclined region.

[0029] Figure 3 This is a schematic diagram of the structure of the interdigital transducer located in the inclined region in another embodiment of this application;

[0030] Figure 4 This is a schematic diagram of the structure of the interdigital transducer located in the inclined region in another embodiment of this application;

[0031] Figure 5 The figures show the admittance curves of the interdigital transducer in Example 1 and the interdigital transducer in the comparative example.

[0032] Figure 6 Q represents the interdigital transducer in Example 1 and the interdigital transducer in the comparative example. bode A graph showing the change in values;

[0033] Figure 7 The figures show the admittance curves of the interdigital transducer in Example 2 and the interdigital transducer in the comparative example.

[0034] Figure 8 Q represents the interdigital transducer in Example 2 and the interdigital transducer in the comparative example. bode A graph showing the change in values;

[0035] Figure 9 This is a schematic diagram of the acoustic resonator in one embodiment of this application. Detailed Implementation

[0036] In order to make the above objectives, features and advantages of the present application more clear and understandable, the detailed description of the embodiments of the present application is made below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in many different ways from what is described herein, and should not be construed as being limited to the embodiments set forth herein, but should be understood to include all possible embodiments that can be made within the scope of the present application.

[0037] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore should not be construed or implied to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present application.

[0038] In addition, the terms "first", "second", "third" and the like are used only for descriptive purposes, and should not be construed as indicating or implying relative importance or implying a specific number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0039] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0041] It is to be understood that when an element as a precursor of the "fixed" or "disposed" to another element, it can be directly on another element or there can be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to another element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only implementation.

[0042] Please refer to Figure 1 The present application provides an interdigital transducer 100, comprising a first bus bar 10, a second bus bar 20 and interdigital electrodes (not marked in the figure). The first bus bar 10 and the second bus bar 20 are spaced apart and arranged opposite to each other along a first direction X. The interdigital electrodes comprise a plurality of first electrode fingers 30 and a plurality of second electrode fingers 40 between the first bus bar 10 and the second bus bar 20. Each first electrode finger 30 and each second electrode finger 40 are arranged opposite to each other in the first direction X. One first electrode finger 30 and one second electrode finger 40 arranged opposite to each other in the first direction X are referred to as an electrode finger group E. One of the electrode finger groups E is connected to the first bus bar 10, and the other is connected to the second bus bar 20. Through the above arrangement, the first bus bar 10 can be connected to the first electrode finger 30 and the second electrode finger 40 at the same time, and the second bus bar 20 can be connected to the first electrode finger 30 and the second electrode finger 40 at the same time, so that the first bus bar 10 and the second bus bar 20 can provide electrical excitation to the first electrode finger 30 and the second electrode finger 40, and the first electrode finger 30 and the second electrode finger 40 can excite a surface acoustic wave. The main propagation direction of the surface acoustic wave is a second direction Y perpendicular to the first direction X. The component of the surface acoustic wave perpendicular to the main propagation direction forms a standing wave between the first bus bar 10 and the second bus bar 20, that is, a transverse mode, which will cause the in-band ripple, in-band flatness and insertion loss and other indicators to deteriorate, and seriously affect the performance of the resonator. Specifically, the length of the second electrode finger 40 is longer than that of the first electrode finger 30.

[0043] The first bus bar 10 and the second bus bar 20 include, between them, an edge region A, a spacing region B, an inclined region C and a central region D arranged along the first direction X. The inclined region C is located between the central region D and the spacing region B, the spacing region B is located between the inclined region C and the edge region A, and the central region D is located on the side of the inclined region C away from the spacing region B. The first electrode finger 30 is located in the edge region A, and the second electrode finger 40 is located in the edge region A, the spacing region B, the inclined region C and the central region D. The part of the second electrode finger 40 located in the edge region A, the spacing region B and the central region D is parallel to the first direction X, and the part of the second electrode finger 40 located in the inclined region C includes a first segment 411, a second segment 412 and a third segment 413 connected in sequence along the first direction X. The first segment 411, the second segment 412 and the third segment 413 are all arranged obliquely relative to the first direction X, and the second segment 412 is opposite to the first segment 411 and the third segment 413 in the direction of oblique arrangement relative to the first direction X. That is, if the first segment 411 is obliquely upward relative to the first direction X, the second segment 412 is obliquely downward relative to the first direction X, and the third segment 413 is obliquely upward relative to the first direction X. If the first segment 411 is obliquely downward relative to the first direction X, the second segment 412 is obliquely upward relative to the first direction X, and the third segment 413 is obliquely downward relative to the first direction X.

[0044] In this way, by arranging the inclined region C, the part of each second electrode finger 40 located in the inclined region C includes the first segment 411, the second segment 412 and the third segment 413 connected in sequence and all arranged obliquely relative to the first direction X, and the second segment 412 is opposite to the first segment 411 and the third segment 413 in the direction of oblique arrangement relative to the first direction X, thereby breaking the boundary condition in the direction perpendicular to the main propagation direction of the surface acoustic wave (i.e. the first direction X), and since the first segment 411, the second segment 412 and the third segment 413 have different acoustic impedances from the parts of the second electrode finger 40 in other regions, the surface acoustic wave can be reflected, thereby inhibiting the excitation of the transverse mode and inhibiting the energy on the transverse edge from leaking onto the bus bar, achieving the purpose of improving the Q value, and the energy is more concentrated between the interdigital electrodes, the conversion efficiency of mechanical energy and electrical energy is higher, and the purpose of improving the electromechanical coupling coefficient is achieved.

[0045] In specific embodiments, each electrode finger group E is arranged between the first bus bar 10 and the second bus bar 20 along the second direction Y. The arrangement direction of the first electrode finger 30 and the second electrode finger 40 in any electrode finger group E is opposite to the arrangement direction of the first electrode finger 30 and the second electrode finger 40 in the adjacent electrode finger group E. For example, the first electrode finger 30 in a certain electrode finger group E is connected to the first bus bar 10, and the second electrode finger 40 is connected to the second bus bar 20, and the first electrode finger 30 in an electrode finger group E adjacent to the electrode finger group E is connected to the second bus bar 20, and the second electrode finger 40 is connected to the first bus bar 10.

[0046] In some embodiments, the edge region A can include a first edge region Al and a second edge region A2 arranged along the first direction X. The first edge region Al can be adjacent to the first bus bar 10, and the first electrode fingers 30 connected to the first bus bar 10 and the second electrode fingers 40 are arranged alternately along the second direction Y in the first edge region Al. The second edge region A2 can be adjacent to the second bus bar 20, and the first electrode fingers 30 connected to the second bus bar 20 and the second electrode fingers 40 are arranged alternately along the second direction Y in the second edge region A2.

[0047] In some embodiments, the spacing region B can include a first spacing region Bl and a second spacing region B2. The first spacing region Bl is adjacent to a side of the first edge region Al away from the first bus bar 10, and the second electrode fingers 40 and the spacing spaces 43 are arranged alternately along the second direction Y in the first spacing region Bl. The second spacing region B2 is adjacent to a side of the second edge region A2 away from the second bus bar 20, and the second electrode fingers 40 and the spacing spaces 43 are arranged alternately along the second direction Y in the second spacing region B2.

[0048] In some embodiments, the number of the tilt regions C can be two, and the two tilt regions C are a first tilt region Cl and a second tilt region C2. The first tilt region Cl is located between the first spacing region Bl and the center region D, and the second tilt region C2 is located between the second spacing region B2 and the center region D.

[0049] In some embodiments, Figure 1 In the illustrated embodiments, the edge region A includes a first edge region Al and a second edge region A2 arranged along the first direction X, the spacing region B includes a first spacing region Bl and a second spacing region B2 arranged along the first direction X, and the tilt region C includes a first tilt region Cl and a second tilt region C2 arranged along the first direction X.

[0050] The first edge region A1 is located between the first bus bar 10 and the first interval region B1, and the first inclined region C1 is located between the first interval region B1 and the center region D. The second edge region A2 is located between the second bus bar 20 and the second interval region B2, and the second inclined region C2 is located between the second interval region B2 and the center region D. Among them, each second electrode finger 40 connected with the first bus bar 10 is parallel to the first direction X in the part of the first edge region A1, the first interval region B1 and the center region D, and each second electrode finger 40 connected with the second bus bar 20 is parallel to the first direction X in the part of the second edge region A2, the second interval region B2 and the center region D. The part of each second electrode finger 40 in the first inclined region C1 and the second inclined region C2 includes a first segment 411, a second segment 412 and a third segment 413 connected in sequence along the first direction X, and the first segment 411, the second segment 412 and the third segment 413 are all inclined relative to the first direction X.

[0051] Please continue to see Figure 1 In the embodiment of the application, the part of the second electrode finger 40 in the center region D is a center segment 42, the center segment 42 is parallel to the first direction X, and the two sides of the center segment 42 in the second direction Y are respectively a first side 421 and a second side 422. One end of the first segment 411 away from the second segment 412 is connected with the center segment 42. The first segment 411 is inclined to the first side 421 of the center segment 42 relative to the center segment 42. The second segment 412 is inclined to the second side 422 of the center segment 42 relative to the first segment 411. The third segment 413 is inclined to the first side 421 of the center segment 42 relative to the second segment 412. Further, the length dimensions of the first segment 411, the second segment 412 and the third segment 413 in the first direction X are equal.

[0052] Please see Figure 2 As shown, in the embodiment, the two side edges of the first segment 411 in the second direction Y are first side edges 4110, the two first side edges 4110 are parallel to each other and are both inclined relative to the first direction X and the second direction Y. The length dimension of the orthogonal projection of each first side edge 4110 in the plane perpendicular to the first direction X is a, and the length dimension of the orthogonal projection in the plane perpendicular to the second direction Y is b.

[0053] The two side edges of the second segment 412 in the second direction Y are second side edges 4120. The two second side edges 4120 are parallel to each other and are both inclined relative to the first direction X and the second direction Y. The length dimension of the orthogonal projection of each second side edge 4120 in the plane perpendicular to the first direction X is 2a, and the length dimension of the orthogonal projection in the plane perpendicular to the second direction Y is b

[0054] The two side edges of the third segment 413 in the second direction Y are third side edges 4130, the two third side edges 4130 are parallel to each other and are arranged obliquely to the first direction X and the second direction Y. The length dimension of the orthographic projection of each third side edge 4130 in the plane perpendicular to the first direction X is a, and the length dimension of the orthographic projection in the plane perpendicular to the second direction Y is b.

[0055] Please refer to Figure 2 to Figure 4 As shown, in specific embodiments, the part of the second electrode finger 40 located in the inclined region C (i.e., the first inclined region C1 or the second inclined region C2) includes N inclined units 41 connected in sequence along the first direction X, each inclined unit 41 includes the first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X. Wherein, N is a positive integer greater than or equal to 1. That is, the part of the second electrode finger 40 located in the first inclined region C1 includes at least one inclined unit 41, each inclined unit 41 includes the above-mentioned first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X; or, the part of the second electrode finger 40 located in the second inclined region C2 includes at least one inclined unit 41, each inclined unit 41 includes the above-mentioned first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X.

[0056] Optionally, N is equal to 1, 2 or 3. Please refer to Figure 2 As shown, when N is equal to 1, the part of the second electrode finger 40 located in the first inclined region C1 includes one inclined unit 41, the inclined unit 41 includes the above-mentioned first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X; and / or, the part of the second electrode finger 40 located in the second inclined region C2 includes one inclined unit 41, the inclined unit 41 includes the above-mentioned first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X.

[0057] Please refer to Figure 3As shown, when N is equal to 2, the portion of the second electrode finger 40 located at the first inclined region C1 includes two inclined units 41 connected in sequence along the first direction X, each of which includes the first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X, that is, the portion of the second electrode finger 40 located at the first inclined region C1 includes the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X; and / or, the portion of the second electrode finger 40 located at the second inclined region C2 includes two inclined units 41 connected in sequence along the first direction X, each of which includes the first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X, that is, the portion of the second electrode finger 40 located at the second inclined region C2 includes the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X.

[0058] Please refer to Figure 4 As shown, when N is equal to 3, the portion of the second electrode finger 40 located at the first inclined region C1 includes three inclined units 41 connected in sequence along the first direction X, each of which includes the first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X, that is, the portion of the second electrode finger 40 located at the first inclined region C1 includes the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X; and / or, the portion of the second electrode finger 40 located at the second inclined region C2 includes three inclined units 41 connected in sequence along the first direction X, each of which includes the first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X, that is, the portion of the second electrode finger 40 located at the second inclined region C2 includes the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X.

[0059] It should be noted that, through long-term practice, the inventors of this application have creatively discovered that the tilt angle θ of the first segment 411 relative to the first direction X should not be too large or too small, and the length W0 of the portion of the second electrode finger 40 located in the tilted region C in the first direction X should not be too large or too small. If θ and W0 are too small, the suppression of the transverse mode and the improvement of the Q value and electromechanical coupling coefficient will be insignificant; if θ and W0 are too large, new modes will be excited, which does not meet the design requirements for miniaturization. θ represents the tilt angle of the first segment 411 relative to the first direction X, tanθ = a / b. The larger a / b is, the larger θ is; conversely, the smaller a / b is, the smaller θ is. W0 represents the length of the portion of the second electrode finger 40 located in the tilted region C in the first direction X, so W0 = N × 3b. The larger b is, the larger W0 is; conversely, the smaller b is, the smaller W0 is. Therefore, the values ​​of θ and W0 can be controlled by controlling the values ​​of a and b.

[0060] Please see Figure 2 Optionally, in embodiments where N equals 1, a and b satisfy: 0.1p ≤ a ≤ 0.15p, 0.3p ≤ b ≤ 0.5p. Here, p represents the interdigital pitch, i.e., the distance between the center lines of two adjacent second electrode fingers 40. Thus, by controlling the values ​​of a and b, the values ​​of θ and W0 are made appropriate, ensuring that new modes are avoided while significantly improving the performance of the resonator, and better meeting the design requirements for miniaturization.

[0061] Please see Figure 3 Optionally, in embodiments where N equals 2, a and b satisfy: 0.1p ≤ a ≤ 0.15p, 0.3p ≤ b ≤ 0.35p. Thus, by controlling the values ​​of a and b, the values ​​of θ and W0 are made moderate, ensuring that new modes are avoided while significantly improving the performance of the resonator, and better meeting the design requirements for miniaturization. Preferably, a equals 0.15μm, and b equals 0.35μm.

[0062] Please see Figure 4 Optionally, in the embodiment where N equals 3, a and b satisfy: 0.1p ≤ a ≤ 0.12p, 0.15p ≤ b ≤ 0.2p. Thus, by controlling the values ​​of a and b, the values ​​of θ and W0 are made moderate, ensuring that new modes are avoided while significantly improving the performance of the resonator, and better meeting the design requirements for miniaturization. a equals 0.1μm, and b equals 0.15μm.

[0063] To illustrate the beneficial effects of the interdigital transducer 100 in this application, a comparative example is provided below, comparing it with the embodiment of this application:

[0064] The resonator of Example 1 is constructed using the interdigital transducer 100 of the present application, and N is equal to 2, i.e. the portion of the second electrode finger 40 located in the first inclined region CI and the second inclined region C2 each comprises two inclined units 41 connected in sequence along the first direction X, and each inclined unit 41 comprises a first segment 411, a second segment 412 and a third segment 413 connected in sequence along the first direction X. a is equal to 0.15 μm, and b is equal to 0.35 μm.

[0065] The resonator of Example 2 is constructed using the interdigital transducer 100 of the present application, and N is equal to 3, i.e. the portion of the second electrode finger 40 located in the first inclined region CI and the second inclined region C2 each comprises three inclined units 41 connected in sequence along the first direction X, and each inclined unit 41 comprises a first segment 411, a second segment 412 and a third segment 413 connected in sequence along the first direction X. a is equal to 0.1 μm, and b is equal to 0.15 μm.

[0066] The difference between the interdigital transducer of the comparative example and the interdigital transducers of Examples 1 and 2 is that the second electrode finger does not comprise inclined units 41, i.e. the portion of the second electrode finger in each region is parallel to the first direction X.

[0067] Figure 5 The admittance curves of the interdigital transducer 100 of Example 1 and the interdigital transducer of the comparative example are shown. Figure 6 The Q value curves of the interdigital transducer 100 of Example 1 and the interdigital transducer of the comparative example are shown. bode Figure 7 The admittance curves of the interdigital transducer 100 of Example 2 and the interdigital transducer of the comparative example are shown. Figure 8 The Q value curves of the interdigital transducer 100 of Example 2 and the interdigital transducer of the comparative example are shown. bode

[0068] Table 1: Comparison of performance parameters of the interdigital transducers 100 of the comparative example, Example 1 and Example 2

[0069] Electromechanical coupling coefficient kt2 Q bode (max)]]> Comparative Example 7.73％ 1680 Example 1 8.17％ 1631 Example 2 8.06％ 1692

[0070] From Figure 5 and Figure 7 it can be seen that the resonant point and the anti-resonant point of the admittance curves of Examples 1 and 2 are obviously shifted, thereby increasing the electromechanical coupling coefficient k t 2 . From Table 1 it can be seen that, compared with the comparative example, the electromechanical coupling coefficient k t 2 of Example 1 is increased by 5.69%, and the electromechanical coupling coefficient k t 2 of Example 2 is increased by 4.27%. From​​Figure 6 、 Figure 8 and Table 1 can be seen that, compared with the comparative example, the maximum value of Q bode of Example 2 is increased by 12.

[0071] From the offset of the resonance point and the anti-resonance point frequency, the resonator built with Example 1 or Example 2 will have a bandwidth of 3MHz. B34 (2010-2025MHz), B39 (1880-1920MHz) are one of the main frequency bands used in time division duplex (TDD) applications of operators, and the corresponding SAW resonator is widely used in the mobile phone RF front-end receiving circuit. For commercial resonators, in this frequency band around 2GHz, a 3MHz bandwidth increase can increase the insertion loss of the edge of the working frequency band by 0.1-0.3dB, which greatly supports resonator design, process margin, etc., and significantly helps commercial resonators to improve competitiveness.

[0072] In summary, the interdigital transducer 100 in Example 1 and Example 2 has a significant effect on improving the electromechanical coupling coefficient and expanding the bandwidth, and the interdigital transducer 100 in the second embodiment 2 can increase the Q value, achieve the purpose of improving the performance of the resonator, and provide strong support for the subsequent development of high-performance resonators.

[0073] On the other hand, according to the above-mentioned interdigital transducer 100, the present application also provides an acoustic resonator. The acoustic resonator comprises a piezoelectric substrate 200 and an interdigital transducer 100 as described in any of the above embodiments, and the interdigital transducer 100 is located on one side of the piezoelectric substrate 200. Wherein, the material of the interdigital transducer 100 can include one or a combination of aluminum, copper, titanium, gold, silver, platinum, and molybdenum; or the material of the interdigital transducer 100 can also be other alloy materials.

[0074] The piezoelectric material in the piezoelectric substrate 200 has a piezoelectric effect, which can realize the mutual conversion of electrical signals and acoustic waves, excite surface acoustic waves through the interaction of the interdigital transducer 100 and the piezoelectric substrate 200, and construct a SAW resonator (surface-acoustic-wave) using the resonant characteristics of the surface acoustic wave.

[0075] In another aspect, according to the above-mentioned acoustic resonator, the present application also provides an electronic device. The electronic device comprises an acoustic resonator as described in any of the above embodiments. It should be noted that the electronic device can be an intermediate product such as a radio frequency front-end, a filter amplification module, etc.; or the electronic device can also be a terminal product such as a mobile phone, a tablet computer, a drone, etc., which is not limited here.

[0076] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, it is to be understood that the application embraces all such possible combinations.

[0077] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. An interdigital transducer, characterized in that, include: The first busbar (10) and the second busbar (20) are arranged at intervals and opposite to each other along the first direction (X); and The interdigitated electrode includes a plurality of first electrode fingers (30) and a plurality of second electrode fingers (40) located between the first busbar (10) and the second busbar (20), wherein each of the first electrode fingers (30) and each of the second electrode fingers (40) are arranged opposite to each other in the first direction (X); among the first electrode fingers (30) and the second electrode fingers (40) arranged opposite to each other in the first direction (X), one of them is connected to the first busbar (10), and the other of them is connected to the second busbar (20); The first busbar (10) and the second busbar (20) include an edge region (A), a spacing region (B), an inclined region (C), and a central region (D) arranged along the first direction (X). The inclined region (C) is located between the central region (D) and the spacing region (B). The spacing region (B) is located between the inclined region (C) and the edge region (A). The central region (D) is located on the side of the inclined region (C) away from the spacing region (B). The first electrode finger (30) is located in the edge region (A). The portion of the second electrode finger (40) located in the edge region (A), the interval region (B), and the center region (D) is parallel to the first direction (X). The portion of the second electrode finger (40) located in the inclined region (C) includes a first segment (411), a second segment (412), and a third segment (413) connected sequentially along the first direction (X). The first segment (411), the second segment (412), and the third segment (413) are all inclined relative to the first direction (X), and the second segment (412) is inclined in the opposite direction to the first segment (411) and the third segment (413) relative to the first direction (X).

2. The interdigital transducer according to claim 1, characterized in that, The portion of the second electrode (40) located in the central region (D) is the central segment (42), and the two sides of the central segment (42) on the second direction (Y) perpendicular to the first direction (X) are the first side (421) and the second side (422), respectively. The first segment (411) is connected to the center segment (42) at one end away from the second segment (412). The first segment (411) is inclined toward the first side (421) of the center segment (42) relative to the center segment (42). The second segment (412) is inclined toward the second side (422) of the center segment (42) relative to the first segment (411). The third segment (413) is inclined toward the first side (421) of the center segment (42) relative to the second segment (412).

3. The interdigital transducer according to claim 2, characterized in that, The first segment (411), the second segment (412), and the third segment (413) have the same length in the first direction (X).

4. The interdigital transducer according to claim 3, characterized in that, The two sides of the first segment (411) in the second direction (Y) are the first side (4110), the two first side (4110) are parallel to each other, and the length of the orthographic projection of the first side (4110) on the plane perpendicular to the first direction (X) is a, and the length of the orthographic projection on the plane perpendicular to the second direction (Y) is b. The two sides of the second segment (412) in the second direction (Y) are the second side (4120), the two second side (4120) are parallel to each other, and the length of the orthographic projection of the second side (4120) on the plane perpendicular to the first direction (X) is 2a, and the length of the orthographic projection on the plane perpendicular to the second direction (Y) is b. The two sides of the third segment (413) in the second direction (Y) are the third side (4130), the two third side (4130) are parallel to each other, and the length of the orthographic projection of the third side (4130) on the plane perpendicular to the first direction (X) is a, and the length of the orthographic projection on the plane perpendicular to the second direction (Y) is b.

5. The interdigital transducer according to claim 4, characterized in that, The portion of the second electrode (40) located in the inclined region (C) includes N inclined units (41) connected in sequence along the first direction (X). Each inclined unit (41) includes a first segment (411), a second segment (412), and a third segment (413) connected in sequence along the first direction (X), where N is a positive integer greater than or equal to 1.

6. The interdigital transducer according to claim 5, characterized in that, N equals 1, 2, or 3.

7. The interdigital transducer according to claim 6, characterized in that, When N equals 1, 0.1p≤a≤0.15p, 0.3p≤b≤0.5p; where p represents the distance between the center lines of two adjacent second electrode fingers (40); When N equals 2, 0.1p ≤ a ≤ 0.15p, 0.3p ≤ b ≤ 0.35p; When N equals 3, 0.1p≤a≤0.12p, 0.15p≤b≤0.2p.

8. The interdigital transducer according to any one of claims 1 to 7, characterized in that, The edge region (A) includes a first edge region (A1) and a second edge region (A2) spaced apart along the first direction (X), the interval region (B) includes a first interval region (B1) and a second interval region (B2) spaced apart along the first direction (X), and the inclined region (C) includes a first inclined region (C1) and a second inclined region (C2) spaced apart along the first direction (X). The first edge region (A1) is located between the first busbar (10) and the first interval region (B1), the first inclined region (C1) is located between the first interval region (B1) and the center region (D), the second edge region (A2) is located between the second busbar (20) and the second interval region (B2), and the second inclined region (C2) is located between the second interval region (B2) and the center region (D).

9. The interdigital transducer according to claim 8, characterized in that, In the first edge region (A1) and the second edge region (A2), the first electrode finger (30) and the second electrode finger (40) are alternately arranged along the second direction (Y), which is perpendicular to the first direction (X).

10. An acoustic resonator comprising a piezoelectric substrate (200) and an interdigital transducer (100) as claimed in any one of claims 1 to 9, the interdigital transducer (100) being disposed on one side of the piezoelectric substrate (200).

11. An electronic device comprising the acoustic resonator as claimed in claim 10.

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