Interdigital transducer, resonator, filter, and electronic device
By designing an interfinger transducer in the surface acoustic wave filter, the combination of reflective components and tilted electrode finger strips is used to solve the problem of poor lateral mode suppression effect, effectively suppressing the surface acoustic wave, reducing losses and fluctuations, and simplifying the preparation process.
Patent Information
- Application Number
- CN202411519803.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-04-08
AI Technical Summary
In the existing surface acoustic wave filters, the suppression effect of the lateral mode is limited, resulting in problems such as increasing resonator loss, fluctuation in Q value, increasing passband fluctuation and increasing insertion loss.
A cross finger transducer is designed. By setting a reflection component and an inclined electrode finger bar, the reflection component can reflect the lateral mode along the length direction of the electrode finger bar, breaking the symmetry of the boundary conditions, and achieving effective suppression of the lateral mode of surface acoustic wave excitation.
The lateral mode of surface acoustic waves is effectively suppressed, the resonator loss is reduced, the Q value fluctuation is reduced, and the problems such as increasing filter passband fluctuations and increasing insertion loss are avoided. At the same time, the preparation difficulty and process cost are reduced.
Smart Images
Figure CN119788019A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of mobile communication equipment, and in particular to an interdigital transducer, a resonator, a filter and an electronic device. Background Art
[0002] Surface acoustic wave filters are widely used in the front end of mobile communication devices. Surface acoustic wave resonators are an important component of surface acoustic wave ladder filters, and their performance affects the transmission characteristics of the filter. Since surface acoustic wave resonators will generate transverse modes during the excitation process, clutter signals will be generated in or near the passband, which will increase the resonator loss and cause Q value fluctuations, ultimately leading to increased passband fluctuations in the filter and increased insertion loss.
[0003] In the related art, the suppression effect on the lateral mode is limited, and the influence caused by the lateral mode cannot be effectively eliminated. Summary of the invention
[0004] The embodiments of the present application provide an IDT to achieve effective suppression of the transverse mode, so as to at least partially solve the above technical problems.
[0005] To achieve the above object, according to a first aspect of the present application, an interdigital transducer is provided, comprising a first bus bar, a second bus bar, a first electrode finger and a second electrode finger, wherein the first electrode finger is connected to the first bus bar, and the second electrode finger is connected to the second bus bar;
[0006] The IDT further comprises a reflection component, and at least one of the first electrode finger strips and the second electrode finger strips is connected to the reflection component;
[0007] A line connecting the connection points of the first electrode fingers and the first bus bar is obliquely intersecting with the first electrode fingers.
[0008] Optionally, the reflective component includes first lateral pseudo fingers, and the extension direction of at least part of the first lateral pseudo fingers is parallel to the connecting line, and / or the extension direction of at least part of the first lateral pseudo fingers is perpendicular to the length direction of the first electrode finger strip.
[0009] Optionally, the IDT includes at least two of the first electrode fingers and at least two of the second electrode fingers, and the first electrode fingers and the second electrode fingers are alternately distributed, wherein:
[0010] The first lateral pseudo-finger at at least one of the first electrode fingers is spaced apart from an adjacent first electrode finger; and / or,
[0011] The first lateral pseudo finger at at least one of the second electrode fingers is spaced apart from an adjacent second electrode finger; and / or,
[0012] The first lateral pseudo-finger at at least one of the first electrode fingers is connected to an adjacent first electrode finger; and / or,
[0013] The first lateral dummy finger at at least one of the second electrode fingers is connected to an adjacent second electrode finger.
[0014] Optionally, the reflective component includes a longitudinal dummy finger and at least two of the first transverse dummy fingers, and the first transverse dummy fingers are connected to the longitudinal dummy fingers to form at least two reflective gratings.
[0015] Optionally, the metallization rate of the first lateral pseudo finger is between 10% and 90%.
[0016] Optionally, an angle between the connection line and the first electrode finger is between -75° and +75°.
[0017] Optionally, the metallization rate of the first electrode fingers is between 10% and 90%; and / or,
[0018] The metallization rate of the second electrode fingers is between 10% and 90%.
[0019] According to a second aspect of the present application, a resonator is further provided, comprising a piezoelectric substrate and the IDT as described above, wherein the IDT is disposed on the piezoelectric substrate.
[0020] Optionally, the resonator further comprises at least two reflection grating structures, at least two of the reflection grating structures and the IDT are arranged on the same side of the piezoelectric substrate, and the IDT is located between the two reflection grating structures.
[0021] Optionally, the reflective grid structure includes a third bus bar, a fourth bus bar and a connecting bar, and the connecting bar connects the third bus bar and the fourth bus bar.
[0022] Optionally, the reflective grid structure also includes a third electrode finger, a fourth electrode finger and a second lateral fake finger, the third electrode finger is connected to the third bus bar, the fourth electrode finger is connected to the fourth bus bar, and at least one of the third electrode finger and the fourth electrode finger is connected to the second lateral fake finger.
[0023] According to a third aspect of the present application, a filter is also provided, comprising the resonator as described above.
[0024] According to a fourth aspect of the present application, a vehicle is also provided, comprising the filter as described above.
[0025] In the interdigital transducer of the embodiment of the present application, a reflective component is provided, which can reflect the transverse mode excited along the length direction of the first electrode finger and / or the length direction of the second electrode finger, thereby reducing the leakage of surface acoustic wave energy. At the same time, the line connecting the connection point of the first electrode finger and the first bus bar is set to be oblique to the first electrode finger, so that the angle between the propagation direction of the surface acoustic wave excited by the interdigital transducer and the line is greater than 0°, thereby breaking the symmetry of the boundary conditions in the length direction of the first electrode finger. In other words, the present application can achieve effective suppression of the transverse mode excited by the surface acoustic wave through the arrangement of the first electrode finger and the second electrode finger, as well as the setting of the reflective component, without introducing changes in material or electrode thickness, greatly reducing the difficulty of preparation and process cost.
[0026] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.
[0028] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings, wherein the same figure numbers represent the same parts in the following description.
[0029] Figure 1 is one of the structural schematic diagrams of the interdigital transducer provided in the exemplary embodiment of the present disclosure;
[0030] Figure 2 is a schematic diagram of directions provided in an exemplary embodiment of the present disclosure;
[0031] Figure 3 is the second schematic diagram of the structure of the interdigital transducer provided in the exemplary embodiment of the present disclosure;
[0032] Figure 4 is one of the structural schematic diagrams of an interdigital transducer provided with longitudinal pseudo fingers provided in an exemplary embodiment of the present disclosure;
[0033] Figure 5 This is the second structural schematic diagram of an interdigital transducer provided with longitudinal pseudo fingers provided in an exemplary embodiment of the present disclosure;
[0034] Figure 6is the third structural schematic diagram of the interdigital transducer provided in the exemplary embodiment of the present disclosure;
[0035] Figure 7 is one of the structural schematic diagrams of a resonator provided in an exemplary embodiment of the present disclosure;
[0036] Figure 8 is the second structural schematic diagram of the resonator provided in the exemplary embodiment of the present disclosure;
[0037] Fig. 9 is the third structural schematic diagram of the resonator provided in the exemplary embodiment of the present disclosure;
[0038] Fig.10 is a fourth structural schematic diagram of a resonator provided in an exemplary embodiment of the present disclosure;
[0039] Fig.11 is a fifth structural schematic diagram of a resonator provided in an exemplary embodiment of the present disclosure;
[0040] Fig.12 is a schematic structural diagram of a resonator of a comparative example provided;
[0041] Fig.13 is one of the admittance parameter curves of the embodiments and comparative examples provided in the exemplary embodiments of the present disclosure;
[0042] Fig.14 It is one of the admittance parameter curves of another embodiment and a comparative example provided in the exemplary embodiment of the present disclosure.
[0043] Description of reference numerals:
[0044] 10. Interdigital transducer; 1. First bus bar; 2. Second bus bar; 3. First electrode finger; 4. Second electrode finger; 5. Reflection component; 6. Piezoelectric substrate; 7. Reflection grid structure; 31. Connection point; 51. First lateral pseudo finger; 52. Longitudinal pseudo finger; 71. Third bus bar; 72. Fourth bus bar; 73. Connection bar; 74. Third electrode finger; 75. Fourth electrode finger; 76. Second lateral pseudo finger. DETAILED DESCRIPTION
[0045] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.
[0046] According to the first aspect of this application, see Figure 1 , Figure 2 and Figure 3 The present disclosure provides an IDT 10. The IDT 10 comprises a first bus bar 1, a second bus bar 2, a first electrode finger 3 and a second electrode finger 4, wherein the first electrode finger 3 is connected to the first bus bar 1, and the second electrode finger 4 is connected to the second bus bar 2;
[0047] The IDT 10 further includes a reflection component 5, and at least one of the first electrode fingers 3 and the second electrode fingers 4 is connected to the reflection component 5;
[0048] A line connecting the connection points 31 of the first electrode fingers 3 and the first bus bar 1 obliquely intersects the first electrode fingers 3 .
[0049] It can be understood that, by providing a reflective component 5, the reflective component 5 can reflect the transverse mode excited along the length direction of the first electrode finger 3 and / or the length direction of the second electrode finger 4, thereby reducing the leakage of surface acoustic wave energy. At the same time, the connection line of the connection point 31 of the first electrode finger 3 and the first bus bar 1 is set to be oblique to the first electrode finger 3, so that the angle between the propagation direction of the surface acoustic wave excited by the interdigital transducer 10 and the connection line is greater than 0°, thereby breaking the symmetry of the boundary conditions in the length direction of the first electrode finger 3. In other words, the present application can achieve effective suppression of the transverse mode excited by the surface acoustic wave through the arrangement of the first electrode finger 3 and the second electrode finger 4, and the setting of the reflective component 5, without introducing changes in material or electrode thickness, which greatly reduces the difficulty of preparation and process cost.
[0050] It can be understood that the sound waves excited by the IDT 10 not only propagate along a preset direction (for ease of explanation and understanding, the text and the drawings use the x direction instead of the preset direction for description), but also a small part of them propagate perpendicular to the x direction (i.e., the aperture direction of the IDT 10, which can also be understood as the length direction of the first electrode finger 3 or the length direction of the second electrode finger 4) to form a transverse mode.
[0051] The electrodes of the interdigital transducer 10 of the present application are inclined electrodes, that is, the angle θ between the line connecting the connection point 31 of the first electrode finger 3 and the first bus bar 1 and the x-direction is greater than 0°, and the angle θ between the line connecting the connection point 31 of the second electrode finger 4 and the second bus bar 2 and the x-direction is greater than 0°, thereby breaking the symmetry line of the boundary condition in the aperture direction. At the same time, the reflection component 5 can reflect the transverse mode excited along the aperture direction, destroy its resonance, reduce the leakage of the surface acoustic wave energy, and thus effectively suppress the transverse mode of the surface acoustic wave.
[0052] In the related art, the transverse mode of the surface acoustic wave is mainly suppressed by the weighted electrode method, the piston electrode method and the inclined electrode method, and the weighted electrode method will lead to a decrease in the quality factor (Q value) of the device; the piston electrode method will greatly increase the difficulty of process implementation when applied to high frequencies; the inclined electrode method has limited suppression effect on the transverse mode. However, the present application sets the connection line between the first electrode finger 3 and the first bus bar 1 to be at an angle greater than 0° with the propagation direction of the surface acoustic wave, and simultaneously sets a reflection component 5 at the first electrode finger 3 and the second electrode finger 4, and uses the reflection mode of the reflection component 5 to achieve effective suppression of the transverse mode excited by the surface acoustic wave, without introducing changes in material or electrode thickness, which greatly reduces the difficulty of preparation and process cost, and ensures the quality factor of the device.
[0053] It can be understood that the line connecting the connection positions of the second electrode fingers 4 and the second bus bar 2 is parallel to the line connecting the connection points 31 of the first electrode fingers 3 and the first bus bar 1 .
[0054] It is understandable that the angle θ between the connecting line of the first electrode finger 3 and the connection point 31 of the first bus bar 1 and the x direction is, for example, 30°, but is not limited to 30°, and the specific angle can be determined according to actual debugging.
[0055] It can be understood that the line connecting the connection point 31 of the first electrode finger 3 and the first bus bar 1 is obliquely intersecting the first electrode finger 3 , which means that the angle between the line and the first electrode finger 3 is not 90°.
[0056] In some examples, the reflective component 5 is, for example, a lateral finger or a lateral reflective grating. The reflective component 5 may also be various structures capable of reflecting surface acoustic waves in the aperture direction.
[0057] In some embodiments, see Figure 5 and Figure 6 The reflective component 5 includes a first transverse pseudo finger 51, and the extension direction of at least part of the first transverse pseudo finger 51 is parallel to the connecting line.
[0058] It can be understood that the angle between the line connecting the connection point 31 of the first electrode finger 3 and the first bus bar 1 and the x-direction is greater than 0°, and the extension direction of the first lateral pseudo-finger 51 is parallel to the line, that is, the angle between the extension direction of the first lateral pseudo-finger 51 and the x-direction is also greater than 0°, so that the first lateral pseudo-finger 51 can effectively reflect the lateral mode.
[0059] In some examples, the number of first lateral dummy fingers 51 connected to one first electrode finger strip 3 is greater than or equal to 2, and the number of first lateral dummy fingers 51 connected to one second electrode finger strip 4 is greater than or equal to 2.
[0060] In some examples, the thickness of the first bus bar 1 , the second bus bar 2 , and the first dummy finger may be the same as the thickness of the first electrode finger 3 and the second electrode finger 4 , or may be thicker.
[0061] In some examples, the IDT 10 is a single-layer or multi-layer film structure formed of, for example, Al, Au, Ag, Cu, Pt or other alloy materials, and the number of pairs of interdigital electrodes is variable.
[0062] In some embodiments, see Figure 3 and Figure 4 , the extension direction of at least part of the first lateral false fingers 51 is perpendicular to the length direction of the first electrode finger strips 3 .
[0063] It can be understood that the propagation direction of the surface acoustic wave, that is, the x-direction, is perpendicular to the length direction of the first electrode finger 3. The extension direction of the first transverse pseudo finger 51 is perpendicular to the length direction of the first electrode finger 3, that is, the extension direction of the first transverse pseudo finger 51 is parallel to the x-direction, and the transverse mode is excited along the length direction of the first electrode finger 3, and the excitation direction of the transverse mode is perpendicular to the first transverse pseudo finger 51, so that the first transverse pseudo finger 51 can effectively reflect the transverse mode.
[0064] In some embodiments, the extension direction of all the first lateral pseudo fingers 51 may be parallel to the connecting line, or the extension direction of all the first lateral pseudo fingers 51 may be perpendicular to the length direction of the first electrode finger strip 3, or the extension direction of some of the first lateral pseudo fingers 51 may be parallel to the connecting line, and the extension direction of another part of the first lateral pseudo fingers 51 may be perpendicular to the length direction of the first electrode finger strip 3.
[0065] In some embodiments, see Figure 3 , Figure 4 , Figure 5 and Figure 6 The IDT 10 includes at least two first electrode fingers 3 and at least two second electrode fingers 4 , and the first electrode fingers 3 and the second electrode fingers 4 are alternately distributed.
[0066] It can be understood that the first electrode fingers 3 and the second electrode fingers 4 are alternately distributed and arranged, which is beneficial to improving the quality of the IDT 10 .
[0067] In some embodiments, see Figure 3 and Figure 4 The first lateral dummy finger 51 at at least one of the first electrode fingers 3 is spaced apart from the adjacent first electrode fingers 3 , so that the lateral mode is reflected by the first lateral dummy finger 51 .
[0068] It can be understood that one end of the first lateral pseudo finger 51 is connected to the first electrode finger 3, and the other end of the first lateral pseudo finger 51 extends to intersect with the extension line of the second electrode finger 4, so that the first lateral pseudo finger 51 can effectively reflect the lateral mode excited along the aperture direction.
[0069] In some embodiments, see Figure 3 and Figure 4 The first lateral dummy finger 51 at at least one of the second electrode fingers 4 is spaced apart from the adjacent second electrode finger 4 , so as to realize the reflection of the lateral mode by the second lateral dummy finger 76 .
[0070] It can be understood that one end of the second lateral pseudo finger 76 is connected to the second electrode finger 4, and the other end of the second lateral pseudo finger 76 extends to intersect with the extension of the first electrode finger 3, so that the second lateral pseudo finger 76 can effectively reflect the lateral mode excited along the aperture direction.
[0071] In some examples, a first lateral pseudo-finger 51 at one of the first electrode fingers 3 is spaced apart from an adjacent first electrode finger 3, and a first lateral pseudo-finger 51 at one of the second electrode fingers 4 is spaced apart from an adjacent second electrode finger 4, and at the same time, an extension direction of the first lateral pseudo-finger 51 is perpendicular to a length direction of the first electrode finger 3 or a length direction of the second electrode finger 4.
[0072] In some embodiments, see Figure 5 and Figure 6 At least one of the first lateral dummy fingers 51 at the first electrode fingers 3 is connected to an adjacent first electrode finger 3 .
[0073] It can be understood that the first lateral pseudo-finger 51 connects two adjacent first electrode finger strips 3 , and the first lateral pseudo-finger 51 and the first electrode finger strips 3 constitute a reflection grating, which can effectively reflect the lateral mode excited along the aperture direction.
[0074] In some embodiments, see Figure 5 and Figure 6 The first lateral false finger 51 at at least one of the second electrode fingers 4 is connected to the adjacent second electrode finger 4 .
[0075] It can be understood that the first lateral pseudo-finger 51 connects two adjacent second electrode finger strips 4 , and the first lateral pseudo-finger 51 and the second electrode finger strips 4 constitute a reflection grating, which can effectively reflect the lateral mode excited along the aperture direction.
[0076] In some examples, a line connecting a connection point 31 between the first electrode finger 3 and the first bus bar 1 is parallel to an extension direction of the first lateral pseudo-finger 51 , wherein a first lateral pseudo-finger 51 at one of the first electrode fingers 3 is connected to an adjacent first electrode finger 3 , and a first lateral pseudo-finger 51 at one of the second electrode fingers 4 is connected to an adjacent second electrode finger 4 .
[0077] In some embodiments, see Figure 4 and Figure 5 The reflection component 5 includes a longitudinal false finger 52 and at least two first transverse false fingers 51, and the first transverse false fingers 51 are connected to the longitudinal false fingers 52 to form at least two reflection grids.
[0078] It can be understood that at least two first transverse pseudo fingers 51 are connected to the longitudinal pseudo fingers 52, so that the longitudinal pseudo fingers 52 and the first transverse pseudo fingers 51 can form at least two reflection gratings, so that the number of reflection gratings is two or more, and at least two reflection gratings can effectively reflect the transverse mode excited along the aperture direction.
[0079] In some examples, the first lateral pseudo finger 51 at one of the first electrode fingers 3 is spaced apart from the adjacent first electrode finger 3, and the first lateral pseudo finger 51 at one of the second electrode fingers 4 is spaced apart from the adjacent second electrode finger 4. Meanwhile, the extension direction of the first lateral pseudo finger 51 is perpendicular to the length direction of the first electrode finger 3 or the length direction of the second electrode finger 4, and at least two lateral pseudo fingers are connected to the longitudinal pseudo finger 52.
[0080] In some examples, the first transverse pseudo finger 51 at the first electrode finger 3 is connected to the adjacent first electrode finger 3, and the first transverse pseudo finger 51 at the second electrode finger 4 is connected to the adjacent second electrode finger 4. The line connecting the connection point 31 of the first electrode finger 3 and the first bus bar 1 is parallel to the extension direction of the first transverse pseudo finger 51, and at least two transverse pseudo fingers are connected to the longitudinal pseudo finger 52.
[0081] In some embodiments, the metallization rate of the first lateral dummy fingers 51 is between 10% and 90%.
[0082] It is understandable that setting the metallization rate of the first lateral pseudo finger 51 between 10% and 90% ensures that the first lateral pseudo finger 51 can effectively reflect the lateral mode, while also preventing the first lateral pseudo finger 51 from affecting the excitation and propagation of the surface acoustic wave in the x direction.
[0083] It can be understood that the metallization rate of the first lateral pseudo finger 51 refers to the proportion of the first lateral pseudo finger 51 in one wavelength, that is, the ratio of the width of the first lateral pseudo finger 51 to half the wavelength.
[0084] Exemplarily, the metallization rate of the first lateral dummy finger 51 is 50%.
[0085] In some embodiments, the angle between the connecting line and the first electrode finger 3 is between -75° and +75°.
[0086] It is understandable that the angle between the connecting line of the first electrode finger 3 and the connection point 31 of the first bus bar 1 and the first electrode finger 3 , ie the angle between the connecting line and the x direction, is set between −75° and +75° to ensure the performance of the IDT 10 .
[0087] Exemplarily, the angle between the connecting line and the x-direction is, for example, 30°.
[0088] In some embodiments, the metallization rate of the first electrode fingers 3 is between 10% and 90%.
[0089] It can be understood that setting the metallization rate of the first electrode fingers 3 between 10% and 90% ensures that the IDT 10 can excite and generate surface acoustic waves in the x direction, thereby ensuring the performance of the IDT 10 .
[0090] It can be understood that the metallization rate of the first electrode fingers 3 refers to the proportion of the first electrode fingers 3 in one wavelength, that is, the ratio of the width of the first electrode fingers 3 to half the wavelength.
[0091] Exemplarily, the metallization rate of the first electrode fingers 3 is 50%.
[0092] In some embodiments, the metallization rate of the second electrode fingers 4 is between 10% and 90%.
[0093] It can be understood that setting the metallization rate of the second electrode fingers 4 between 10% and 90% ensures that the IDT 10 can excite and generate surface acoustic waves in the x direction, thereby ensuring the performance of the IDT 10 .
[0094] It can be understood that the metallization rate of the second electrode fingers 4 refers to the proportion of the second electrode fingers 4 in one wavelength, that is, the ratio of the width of the second electrode fingers 4 to half the wavelength.
[0095] Exemplarily, the metallization rate of the second electrode fingers 4 is 50%.
[0096] The following is an introduction to the preparation method of the interdigital transducer 10. The preparation method mainly includes the following steps:
[0097] (i) preparing a corresponding mask according to the structure of the IDT 10, which may be a mask with a positive photoresist pattern or a negative photoresist pattern;
[0098] (ii) cleaning the piezoelectric substrate 6 to remove dust or impurity ions on the surface;
[0099] (iii) performing photolithography on the substrate to obtain a photoresist pattern of a corresponding device;
[0100] (iv) depositing a thin film of electrode material;
[0101] (v) soaking in acetone solution and ultrasonic cleaning, and then peeling to obtain the corresponding device;
[0102] (vi) cutting the wafer to obtain discrete devices;
[0103] (vii) Packaging of discrete devices.
[0104] The surface acoustic wave device realized by the method provided by the present invention has the following advantages:
[0105] (i) It can effectively suppress the transverse mode of surface acoustic waves.
[0106] (ii) The provided structure can choose not to introduce changes in materials or electrode thickness, which greatly reduces the difficulty of preparation and process cost.
[0107] The surface acoustic wave devices realized based on this structure, such as resonators and filters, have reduced clutter signals in the passband, improved performance in all aspects, higher Q value and smaller insertion loss.
[0108] According to the second aspect of this application, refer to Figure 7 The present disclosure provides a resonator. The resonator includes a piezoelectric substrate 6 and an IDT 10 , wherein the IDT 10 is disposed on the piezoelectric substrate 6 .
[0109] It can be understood that the IDT 10 is disposed on the piezoelectric substrate 6 , and the IDT 10 can excite surface acoustic waves propagating along the x-direction and transverse modes propagating along the length direction of the first electrode fingers 3 .
[0110] By providing a reflective component 5, the reflective component 5 can reflect the transverse mode excited along the length direction of the first electrode finger 3 and / or the length direction of the second electrode finger 4, thereby reducing the leakage of the surface acoustic wave energy. At the same time, the connection line of the connection point 31 of the first electrode finger 3 and the first bus bar 1 is set to be oblique to the first electrode finger 3, so that the angle between the propagation direction of the surface acoustic wave excited by the interdigital transducer 10 and the connection line is greater than 0°, thereby breaking the symmetry of the boundary conditions in the length direction of the first electrode finger 3. In other words, the present application can achieve effective suppression of the transverse mode excited by the surface acoustic wave through the arrangement of the first electrode finger 3 and the second electrode finger 4, as well as the setting of the reflective component 5, reduce the resonator loss, reduce the Q value fluctuation, avoid the occurrence of adverse effects such as increased filter passband fluctuation and increased insertion loss, and there is no need to introduce changes in material or electrode thickness, which greatly reduces the difficulty of preparation and process cost.
[0111] In some examples, the piezoelectric substrate 6 may be a single-layer or multi-layer film structure substrate formed of a piezoelectric single crystal, piezoelectric ceramics or other piezoelectric materials. The piezoelectric material may be quartz, LiNbO3, LiTaO3, AlN, ScAlN, ZnO or other materials with piezoelectric properties.
[0112] In some embodiments, see Figure 7 , Figure 8 , Fig. 9 , Fig.10 and Fig.11 The resonator further includes at least two reflection grating structures 7 . The at least two reflection grating structures 7 and the IDT 10 are disposed on the same side of the piezoelectric substrate 6 . The IDT 10 is located between the two reflection grating structures 7 .
[0113] It can be understood that the reflective grating structure 7 is used for surface acoustic wave emission, and by providing the reflective component 5 on the interdigital transducer 10, the resonator can effectively suppress the in-band clutter generated by the transverse mode.
[0114] In some embodiments, see Figure 8 The reflective grid structure 7 includes a third bus bar 71 , a fourth bus bar 72 and a connecting bar 73 , and the connecting bar 73 connects the third bus bar 71 and the fourth bus bar 72 .
[0115] It can be understood that the third bus bar 71 and the fourth bus bar 72 are connected via the connecting bar 73 to form the reflective grid structure 7 .
[0116] In some embodiments, see Figure 8The reflective grid structure 7 also includes a third electrode finger 74, a fourth electrode finger 75 and a second lateral fake finger 76, the third electrode finger 74 is connected to the third bus bar 71, the fourth electrode finger 75 is connected to the fourth bus bar 72, and at least one of the third electrode finger 74 and the fourth electrode finger 75 is connected to the second lateral fake finger 76.
[0117] It can be understood that the second lateral false finger 76 can reflect the lateral mode, so that the reflective grating structure 7 can also suppress the in-passband clutter generated by the lateral mode, so as to improve the suppression effect of the in-passband clutter.
[0118] Fig.13 Shown Figure 7 Embodiments and Fig.10 The simulation results of the admittance curve of the comparative example. It can be seen Fig.10 In the comparative example, the transverse mode will cause fluctuations in the passband within the dashed box, while Figure 7 In the embodiment, the addition of the reflective component 5 effectively suppresses the in-passband clutter generated by the transverse mode.
[0119] Fig.14 Shown Fig. 9 Embodiments and Fig.10 The simulation results of the admittance curve of the comparative example. It can be seen Figure 7 In the embodiment, the addition of the reflective component 5 effectively suppresses the in-passband clutter generated by the transverse mode.
[0120] According to a third aspect of the present application, the present disclosure provides a filter, wherein the filter comprises the above-mentioned resonator.
[0121] It can be understood that, by providing a reflective component 5, the reflective component 5 can reflect the transverse mode excited along the length direction of the first electrode finger 3 and / or the length direction of the second electrode finger 4, thereby reducing the leakage of the surface acoustic wave energy. At the same time, the connection line of the connection point 31 of the first electrode finger 3 and the first bus bar 1 is set to be oblique to the first electrode finger 3, so that the angle between the propagation direction of the surface acoustic wave excited by the interdigital transducer 10 and the connection line is greater than 0°, thereby breaking the symmetry of the boundary conditions in the length direction of the first electrode finger 3. In other words, the present application can achieve effective suppression of the transverse mode excited by the surface acoustic wave through the arrangement of the first electrode finger 3 and the second electrode finger 4, as well as the setting of the reflective component 5, reduce the resonator loss, reduce the Q value fluctuation, avoid the occurrence of adverse effects such as increased filter passband fluctuation and increased insertion loss, and there is no need to introduce changes in material or electrode thickness, which greatly reduces the difficulty of preparation and process cost.
[0122] According to a fourth aspect of the present application, the present disclosure provides a vehicle, wherein the vehicle comprises the filter described above.
[0123] It can be understood that, by providing a reflective component 5, the reflective component 5 can reflect the transverse mode excited along the length direction of the first electrode finger 3 and / or the length direction of the second electrode finger 4, thereby reducing the leakage of the surface acoustic wave energy. At the same time, the connection line of the connection point 31 of the first electrode finger 3 and the first bus bar 1 is set to be oblique to the first electrode finger 3, so that the angle between the propagation direction of the surface acoustic wave excited by the interdigital transducer 10 and the connection line is greater than 0°, thereby breaking the symmetry of the boundary conditions in the length direction of the first electrode finger 3. In other words, the present application can achieve effective suppression of the transverse mode excited by the surface acoustic wave through the arrangement of the first electrode finger 3 and the second electrode finger 4, as well as the setting of the reflective component 5, reduce the resonator loss, reduce the Q value fluctuation, avoid the occurrence of adverse effects such as increased filter passband fluctuation and increased insertion loss, and there is no need to introduce changes in material or electrode thickness, which greatly reduces the difficulty of preparation and process cost.
[0124] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0125] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.
[0126] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.
[0127] The above are only preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.
Claims
1. An interdigital transducer, characterized in that: comprising a first bus bar, a second bus bar, a first electrode finger and a second electrode finger, wherein the first electrode finger is connected to the first bus bar, and the second electrode finger is connected to the second bus bar; The IDT further comprises a reflection component, and at least one of the first electrode finger strips and the second electrode finger strips is connected to the reflection component; A line connecting the connection points of the first electrode fingers and the first bus bar is obliquely intersecting with the first electrode fingers.
2. The interdigital transducer according to claim 1, characterized in that: The reflective component comprises first lateral pseudo fingers, and an extension direction of at least part of the first lateral pseudo fingers is parallel to the connecting line, and / or an extension direction of at least part of the first lateral pseudo fingers is perpendicular to a length direction of the first electrode finger strip.
3. The interdigital transducer according to claim 2, characterized in that: The interdigital transducer comprises at least two of the first electrode fingers and at least two of the second electrode fingers, and the first electrode fingers and the second electrode fingers are alternately arranged, wherein: The first lateral pseudo-finger at at least one of the first electrode fingers is spaced apart from an adjacent first electrode finger; and / or, The first lateral pseudo finger at at least one of the second electrode fingers is spaced apart from an adjacent second electrode finger; and / or, The first lateral pseudo-finger at at least one of the first electrode fingers is connected to an adjacent first electrode finger; and / or, The first lateral dummy finger at at least one of the second electrode fingers is connected to an adjacent second electrode finger.
4. The interdigital transducer according to claim 3, characterized in that: The reflective component includes a longitudinal dummy finger and at least two of the first transverse dummy fingers, wherein the first transverse dummy fingers are connected with the longitudinal dummy fingers to form at least two reflective gratings.
5. The interdigital transducer according to claim 2, characterized in that: The metallization rate of the first lateral dummy finger is between 10% and 90%.
6. The interdigital transducer according to any one of claims 1 to 5, characterized in that: The angle between the connecting line and the first electrode finger is between -75° and +75°.
7. The interdigital transducer according to any one of claims 1 to 5, characterized in that: The metallization rate of the first electrode fingers is between 10% and 90%; and / or, The metallization rate of the second electrode fingers is between 10% and 90%.
8. A resonator, characterized in that: The invention comprises a piezoelectric substrate and the interdigital transducer according to any one of claims 1 to 7, wherein the interdigital transducer is arranged on the piezoelectric substrate.
9. The resonator according to claim 8, characterized in that The resonator further comprises at least two reflection grating structures. The at least two reflection grating structures and the interdigital transducer are arranged on the same side of the piezoelectric substrate. The interdigital transducer is located between the two reflection grating structures.
10. The resonator according to claim 9, characterized in that The reflective grid structure includes a third bus bar, a fourth bus bar and a connecting bar, wherein the connecting bar connects the third bus bar and the fourth bus bar.
11. The resonator according to claim 10, characterized in that The reflective grid structure also includes a third electrode finger, a fourth electrode finger and a second lateral fake finger, the third electrode finger is connected to the third bus bar, the fourth electrode finger is connected to the fourth bus bar, and at least one of the third electrode finger and the fourth electrode finger is connected to the second lateral fake finger.
12. A filter, characterized in that: Comprising a resonator as claimed in any one of claims 8 to 11.
13. A vehicle, characterized in that: Comprising the filter as claimed in claim 12.