CN119788019A - Interdigital transducers, resonators, filters and electronic devices - Google Patents

Abstract

The present application relates to an IDT, a resonator, a filter and an electronic device, wherein the IDT comprises 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 also comprises a reflection component, wherein at least one of the first electrode finger and the second electrode finger is connected to the reflection component; and the line connecting the connection point between the first electrode finger and the first bus bar is obliquely intersected with the first electrode finger. The IDT of the present application can effectively suppress the transverse mode excited by the surface acoustic wave.

Description

Interdigital transducer, resonator, filter, and electronic device

Technical Field

The present application relates to the field of mobile communication devices, and in particular, to an interdigital transducer, a resonator, a filter, and an electronic device.

Background

Surface acoustic wave filters are widely used in front-ends of mobile communication devices. The surface acoustic wave resonator is an important component for realizing the surface acoustic wave ladder filter, and the performance of the surface acoustic wave resonator influences the transmission characteristic of the filter. Because the surface acoustic wave resonator can generate a transverse mode in the excitation process, clutter signals are generated in or near the passband, so that the loss of the resonator is increased, the Q value fluctuates, and finally the filter has adverse effects of increased passband fluctuation, increased insertion loss and the like.

In the related art, the suppression effect on the lateral mode is limited, and the influence caused by the lateral mode cannot be well excluded.

Disclosure of Invention

The embodiment of the application provides an interdigital transducer which can effectively inhibit a transverse mode so as to at least partially solve the technical problems.

In order to achieve the above object, according to a first aspect of the present application, there is provided an interdigital transducer including a first bus bar, a second bus bar, a first electrode finger connected to the first bus bar, and a second electrode finger connected to the second bus bar;

The interdigital transducer further comprises a reflecting component, and at least one of the first electrode finger and the second electrode finger is connected with the reflecting component;

And the connecting line of the connecting point of the first electrode finger strip and the first bus bar is oblique to the first electrode finger strip.

Optionally, the reflection assembly includes a first lateral dummy finger, at least part of which extends in parallel with the connecting line and/or in perpendicular to the length direction of the first electrode finger.

Optionally, the interdigital transducer comprises at least two first electrode fingers and at least two second electrode fingers, wherein the first electrode fingers and the second electrode fingers are alternately distributed,

The first lateral dummy finger at least one of the first electrode fingers being spaced apart from an adjacent one of the first electrode fingers, and/or,

The first lateral dummy finger at least one of the second electrode fingers being spaced apart from an adjacent one of the second electrode fingers, and/or,

At least one of the first lateral dummy fingers at the first electrode finger, connected to an adjacent first electrode finger, and/or,

The first lateral dummy finger at least one of the second electrode fingers is connected to an adjacent one of the second electrode fingers.

Optionally, the reflective assembly includes a longitudinal artificial finger and at least two of the first transverse artificial fingers, the first transverse artificial fingers being connected with the longitudinal artificial fingers to form at least two reflective gratings.

Optionally, the metallization rate of the first transverse artificial finger is between 10% and 90%.

Optionally, an included angle between the connecting line and the first electrode finger is between-75 ° and +75°.

Optionally, the first electrode finger has a metallization ratio of between 10% and 90%, and/or,

The metallization rate of the second electrode finger is between 10% and 90%.

According to a second aspect of the present application there is also provided a resonator comprising a piezoelectric substrate and an interdigital transducer as described above, the interdigital transducer being provided on the piezoelectric substrate.

Optionally, the resonator further includes at least two reflection grating structures, at least two reflection grating structures and the interdigital transducer are disposed on the same side of the piezoelectric substrate, and the interdigital transducer is disposed between the two reflection grating structures.

Optionally, the reflective grid structure includes a third bus bar, a fourth bus bar, and a connection bar connecting the third bus bar and the fourth bus bar.

Optionally, the reflective grating structure further includes a third electrode finger, a fourth electrode finger, and a second lateral dummy 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 dummy finger.

According to a third aspect of the application there is also provided a filter comprising a resonator as described above.

According to a fourth aspect of the application there is also provided a vehicle comprising a filter as described above.

In the interdigital transducer provided by the embodiment of the application, the reflection assembly is arranged, so that the reflection assembly 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, and the leakage of the acoustic surface wave energy is reduced. Meanwhile, the connecting line of the connecting point of the first electrode finger and the first bus bar is arranged to be oblique with the first electrode finger, so that the included angle between the propagation direction of the acoustic surface wave excited by the interdigital transducer and the connecting line is larger than 0 degrees, and the symmetry of boundary conditions in the length direction of the first electrode finger can be broken. That is, the arrangement of the first electrode finger strips and the second electrode finger strips and the arrangement of the reflecting component can effectively inhibit the transverse mode excited by the surface acoustic wave, and the preparation difficulty and the process cost are greatly reduced without introducing materials or changing the thickness of the electrodes.

Additional features and advantages of the application will be set forth in the detailed description which follows.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the description of the embodiments will be briefly described below. It is evident that the drawings in the following description are only some embodiments of the application and that other drawings may be obtained from these drawings without inventive effort for a person skilled in the art.

For a more complete understanding of the present application and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts throughout the following description.

FIG. 1 is one of the schematic structural diagrams of an interdigital transducer provided in an exemplary embodiment of the present disclosure;

FIG. 2 is a schematic view of directions provided in an exemplary embodiment of the present disclosure;

FIG. 3 is a second schematic diagram of an interdigital transducer provided in an exemplary embodiment of the present disclosure;

FIG. 4 is one of the structural schematic diagrams of an interdigital transducer provided in an exemplary embodiment of the present disclosure with a longitudinal interdigital transducer;

FIG. 5 is a second schematic diagram of an interdigital transducer provided in an exemplary embodiment of the present disclosure with a longitudinal interdigital transducer;

FIG. 6 is a third schematic structural view of an interdigital transducer provided in an exemplary embodiment of the present disclosure;

FIG. 7 is one of the structural schematic diagrams of the resonator provided in the exemplary embodiments of the present disclosure;

FIG. 8 is a second schematic diagram of a resonator provided in an exemplary embodiment of the present disclosure;

FIG. 9 is a third schematic structural view of a resonator provided in an exemplary embodiment of the present disclosure;

FIG. 10 is a fourth schematic diagram of a resonator provided in an exemplary embodiment of the present disclosure;

FIG. 11 is a fifth schematic structural view of a resonator provided in an exemplary embodiment of the present disclosure;

FIG. 12 is a schematic diagram of the structure of a resonator of the comparative example provided;

FIG. 13 is one of the admittance parameter graphs of the examples and comparative examples provided in exemplary embodiments of the present disclosure;

Fig. 14 is one of the admittance parameter graphs of another example and comparative example provided in exemplary embodiments of the present disclosure.

Reference numerals illustrate:

10. Interdigital transducer, 1, first bus bar, 2, second bus bar, 3, first electrode finger bar, 4, second electrode finger bar, 5, reflection component, 6, piezoelectric substrate, 7, reflection grid structure, 31, connection point, 51, first transverse artificial finger, 52, longitudinal artificial finger, 71, third bus bar, 72, fourth bus bar, 73, connection bar, 74, third electrode finger bar, 75, fourth electrode finger bar, 76, second transverse artificial finger.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. All other embodiments, which can be made by a person skilled in the art without any inventive effort, are intended to be within the scope of the present application based on the embodiments of the present application.

Referring to fig. 1,2 and 3, in accordance with a first aspect of the present disclosure, an interdigital transducer 10 is provided. The interdigital transducer 10 includes a first bus bar 1, a second bus bar 2, a first electrode finger 3, and a second electrode finger 4, the first electrode finger 3 being connected to the first bus bar 1, the second electrode finger 4 being connected to the second bus bar 2;

The interdigital transducer 10 further comprises a reflecting component 5, and at least one of the first electrode finger 3 and the second electrode finger 4 is connected with the reflecting component 5;

The connection line of the connection point 31 of the first electrode finger 3 and the first bus bar 1 is oblique to the first electrode finger 3.

It will be appreciated that by providing the reflecting assembly 5, the reflecting assembly 5 may reflect transverse modes excited along the length of the first electrode finger 3 and/or the length of the second electrode finger 4, reducing leakage of acoustic surface wave energy. Meanwhile, the connecting line of the connecting 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 included angle between the propagation direction of the acoustic surface wave excited by the interdigital transducer 10 and the connecting line is larger than 0 degrees, and the symmetry of boundary conditions in the length direction of the first electrode finger 3 can be broken. That is, the arrangement of the first electrode finger 3 and the second electrode finger 4 and the arrangement of the reflecting component 5 can effectively inhibit the transverse mode excited by the surface acoustic wave, and the preparation difficulty and the process cost are greatly reduced without introducing materials or changing the thickness of the electrodes.

It will be appreciated that, in addition to propagating along a predetermined direction (for ease of illustration and understanding, the description and drawings herein use the x-direction instead of the predetermined direction), a small portion of the acoustic wave excited by the interdigital transducer 10 propagates perpendicular to the x-direction (i.e., the aperture direction of the interdigital transducer 10, and may also be understood as the length direction of the first electrode finger 3 or the length direction of the second electrode finger 4), forming a transverse mode.

The electrode of the interdigital transducer 10 is an inclined electrode, namely, the included angle theta between the connecting line of the connecting point 31 of the first electrode finger 3 and the first bus bar 1 and the x direction is larger than 0 degrees, and the included angle theta between the connecting line of the connecting point 31 of the second electrode finger 4 and the second bus bar 2 and the x direction is larger than 0 degrees, so that the symmetrical line of the boundary condition of the aperture direction can be broken. Meanwhile, the reflection assembly 5 can reflect the transverse mode excited along the aperture direction, destroy resonance of the transverse mode, reduce leakage of acoustic surface wave energy, and further effectively inhibit the transverse mode of the acoustic surface wave.

In the related art, the transverse mode of the surface acoustic wave is mainly inhibited through a weighted electrode method, a Piston electrode method and an inclined electrode method, the quality factor (Q value) of a device is reduced through the weighted electrode method, the technological implementation difficulty is greatly increased when the Piston electrode method is applied to high frequency, and the inhibiting effect of the inclined electrode method on the transverse mode is limited. The connecting line of the first electrode finger 3 and the first bus bar 1 is set to form an included angle larger than 0 DEG with the propagation direction of the sound surface wave, and the reflecting component 5 is arranged at the positions of the first electrode finger 3 and the second electrode finger 4, so that the effective suppression of the transverse mode excited by the sound surface wave is realized by utilizing the reflecting mode of the reflecting component 5, the material or the change of the thickness of the electrode is not required to be introduced, the preparation difficulty and the process cost are greatly reduced, and the quality factor of the device is ensured.

It will be appreciated that the connection of the second electrode finger 4 to the connection location of the second bus bar 2 is parallel to the connection of the first electrode finger 3 to the connection point 31 of the first bus bar 1.

It is understood that the angle θ between the line connecting 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 deg., and the specific degree may be determined according to actual debugging.

It will be appreciated that the connection line of the connection point 31 of the first electrode finger 3 to the first bus bar 1 is oblique to the first electrode finger 3, meaning that the angle between the connection line and the first electrode finger 3 is not 90 °.

In some examples, the reflective component 5 is, for example, a lateral artificial finger or a lateral reflective grating. The reflection assembly 5 may also have various structures capable of realizing a surface acoustic wave in the reflection aperture direction.

In some embodiments, referring to fig. 5 and 6, the reflective assembly 5 includes a first lateral dummy finger 51, at least a portion of the first lateral dummy finger 51 extending parallel to the line.

It can be understood that the included angle between the connection line of the first electrode finger 3 and the connection point 31 of the first bus bar 1 and the x direction is greater than 0 °, and the extending direction of the first transverse artificial finger 51 is parallel to the connection line, that is, the included angle between the extending direction of the first transverse artificial finger 51 and the x direction is also greater than 0 °, so that the first transverse artificial finger 51 can effectively reflect the transverse mode.

In some examples, the number of first lateral dummy fingers 51 connected to one first electrode finger 3 is greater than or equal to 2, and the number of first lateral dummy fingers 51 connected to one second electrode finger 4 is greater than or equal to 2.

In some examples, the thicknesses of the first bus bar 1, the second bus bar 2, and the first dummy finger may be the same as or greater than the thicknesses of the first electrode finger 3 and the second electrode finger 4.

In some examples, the interdigital transducer 10 can be, for example, a single or multi-layer film structure formed of Al, au, ag, cu, pt or other alloy materials, with a variable interdigital electrode pair number.

In some embodiments, referring to fig. 3 and 4, at least a portion of the first lateral dummy finger 51 extends perpendicular to the length of the first electrode finger strip 3.

It will be appreciated that the propagation direction of the surface acoustic wave, i.e. the x-direction, is perpendicular to the length direction of the first electrode finger 3. The extending direction of the first transverse artificial finger 51 is perpendicular to the length direction of the first electrode finger strip 3, that is, the extending direction of the first transverse artificial finger 51 is parallel to the x direction, and the transverse mode is excited along the length direction of the first electrode finger strip 3, and the exciting direction of the transverse mode is perpendicular to the first transverse artificial finger 51, so that the first transverse artificial finger 51 can effectively reflect the transverse mode.

In some embodiments, the extending directions of all the first transverse artificial fingers 51 may be parallel to the connecting line, or the extending directions of all the first transverse artificial fingers 51 may be perpendicular to the length direction of the first electrode finger strips 3, or the extending directions of part of the first transverse artificial fingers 51 may be parallel to the connecting line, and the extending directions of the other part of the first transverse artificial fingers 51 may be perpendicular to the length direction of the first electrode finger strips 3.

In some embodiments, referring to fig. 3,4, 5, and 6, the interdigital transducer 10 includes at least two first electrode fingers 3 and at least two second electrode fingers 4, the first electrode fingers 3 and the second electrode fingers 4 being alternately distributed.

It will be appreciated that the alternating arrangement of the first electrode fingers 3 and the second electrode fingers 4 is beneficial for improving the quality of the interdigital transducer 10.

In some embodiments, referring to fig. 3 and 4, a first lateral dummy finger 51 at least one of the first electrode fingers 3 is spaced apart from an adjacent first electrode finger 3 to achieve reflection of the lateral mode with the first lateral dummy finger 51.

It will be appreciated that one end of the first transverse artificial finger 51 is connected to the first electrode finger 3, and the other end of the first transverse artificial finger 51 extends to intersect the extension line of the second electrode finger 4, so that the first transverse artificial finger 51 can effectively reflect the transverse mode excited along the aperture direction.

In some embodiments, referring to fig. 3 and 4, the first lateral dummy finger 51 at least one of the second electrode fingers 4 is spaced apart from an adjacent second electrode finger 4 to achieve reflection of the lateral mode with the second lateral dummy finger 76.

It will be appreciated that one end of the second transverse artificial finger 76 is connected to the second electrode finger strip 4 and the other end of the second transverse artificial finger 76 extends to intersect the extension of the first electrode finger strip 3 so that the second transverse artificial finger 76 can effectively reflect the transverse mode excited along the aperture direction.

In some examples, the first lateral dummy finger 51 at one of the first electrode fingers 3 is spaced apart from the adjacent first electrode finger 3, and the first lateral dummy finger 51 at one of the second electrode fingers 4 is spaced apart from the adjacent second electrode finger 4, while the first lateral dummy finger 51 extends in a direction perpendicular to the longitudinal direction of the first electrode finger 3 or the longitudinal direction of the second electrode finger 4.

In some embodiments, referring to fig. 5 and 6, a first transverse finger 51 at least one of the first electrode fingers 3 is connected to an adjacent first electrode finger 3.

It will be appreciated that the first transverse artificial finger 51 connects two adjacent first electrode fingers 3, the first transverse artificial finger 51 and the first electrode fingers 3 forming a reflective grating which is effective to reflect the excited transverse mode along the aperture direction.

In some embodiments, referring to fig. 5 and 6, a first lateral dummy finger 51 at least one of the second electrode fingers 4 is connected to an adjacent second electrode finger 4.

It will be appreciated that the first transverse artificial finger 51 connects two adjacent second electrode fingers 4, the first transverse artificial finger 51 and the second electrode fingers 4 forming a reflective grating which is effective to reflect the excited transverse mode along the aperture direction.

In some examples, the connection of the first electrode finger 3 to the connection point 31 of the first bus bar 1 is parallel to the extending direction of the first lateral dummy finger 51, wherein the first lateral dummy finger 51 at one first electrode finger 3 is connected to the adjacent first electrode finger 3, and the first lateral dummy finger 51 at one second electrode finger 4 is connected to the adjacent second electrode finger 4.

In some embodiments, referring to fig. 4 and 5, the reflective assembly 5 includes a longitudinal artificial finger 52 and at least two first transverse artificial fingers 51, the first transverse artificial fingers 51 being connected with the longitudinal artificial fingers 52 to form at least two reflective gratings.

It will be appreciated that at least two first transverse artificial fingers 51 are each connected to the longitudinal artificial finger 52 such that the longitudinal artificial finger 52 and the first transverse artificial finger 51 may constitute at least two reflective gratings such that the number of reflective gratings is two or more, the at least two reflective gratings being effective to reflect a transverse mode excited along the aperture direction.

In some examples, the first lateral dummy finger 51 at one of the first electrode fingers 3 is spaced apart from an adjacent first electrode finger 3, and the first lateral dummy finger 51 at one of the second electrode fingers 4 is spaced apart from an adjacent second electrode finger 4. Meanwhile, the extending direction of the first transverse artificial 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 transverse artificial fingers are connected with the longitudinal artificial finger 52.

In some examples, a first lateral dummy finger 51 at a first electrode finger 3 is connected to an adjacent first electrode finger 3, and a first lateral dummy finger 51 at a second electrode finger 4 is connected to an adjacent second electrode finger 4. The connection line of the first electrode finger 3 to the connection point 31 of the first bus bar 1 is parallel to the extending direction of the first lateral dummy finger 51, and at least two lateral dummy fingers are connected to the longitudinal dummy finger 52.

In some embodiments, the metallization rate of the first transverse artificial finger 51 is between 10% and 90%.

It can be understood that the metallization rate of the first transverse artificial finger 51 is set between 10% and 90%, so that the first transverse artificial finger 51 can effectively reflect the transverse mode, and meanwhile, the influence of the first transverse artificial finger 51 on the excitation and propagation of the acoustic surface wave in the x direction can be avoided.

It is understood that the metallization ratio of the first transverse artificial finger 51 refers to the ratio of the first transverse artificial finger 51 to the one wavelength, i.e. the ratio of the width of the first transverse artificial finger 51 to the half wavelength.

Illustratively, the metallization rate of the first transverse artificial finger 51 is 50%.

In some embodiments, the connection line makes an angle of between-75 ° and +75° with the first electrode finger 3.

It will be appreciated that the angle between the connection line of the first electrode finger 3 and the connection point 31 of the first bus bar 1 and the first electrode finger 3, i.e. the angle between the connection line and the x direction is set between-75 ° and +75°, so as to ensure the performance of the interdigital transducer 10.

The angle between the line and the x-direction is for example 30 °.

In some embodiments, the metallization rate of the first electrode finger 3 is between 10% and 90%.

It can be understood that the metallization rate of the first electrode finger 3 is set between 10% and 90%, so that the interdigital transducer 10 can excite and generate surface acoustic waves in the x direction, and the performance of the interdigital transducer 10 is ensured.

It is understood that the metallization ratio of the first electrode finger 3 refers to the ratio of the first electrode finger 3 to one wavelength, i.e. the ratio of the width of the first electrode finger 3 to half wavelength.

The metallization rate of the first electrode finger 3 is, for example, 50%.

In some embodiments, the metallization rate of the second electrode finger 4 is between 10% and 90%.

It can be understood that the metallization rate of the second electrode finger 4 is set between 10% and 90%, so that the interdigital transducer 10 can excite and generate surface acoustic waves in the x direction, and the performance of the interdigital transducer 10 is ensured.

It is understood that the metallization ratio of the second electrode finger 4 refers to the proportion of the second electrode finger 4 that is occupied in one wavelength, i.e. the ratio of the width of the second electrode finger 4 to half wavelength.

The metallization rate of the second electrode finger 4 is, for example, 50%.

The method of making the interdigital transducer 10 is described below. The preparation method mainly comprises the following steps:

(i) Preparing a corresponding mask plate which can be a positive photoresist pattern or a negative photoresist pattern mask plate according to the structure of the interdigital transducer 10;

(ii) Cleaning the piezoelectric substrate 6 to remove dust or impurity ions on the surface;

(iii) Photoetching the substrate to obtain photoresist patterns of corresponding devices;

(iv) Depositing a thin film of electrode material;

(v) Soaking in acetone solution, ultrasonic cleaning, and stripping to obtain corresponding devices;

(vi) Cutting the wafer to obtain discrete devices;

(vii) And packaging the discrete device.

The surface acoustic wave device realized by the method provided by the invention has the following advantages:

(i) The transverse mode of the surface acoustic wave can be effectively suppressed.

(Ii) The provided structure can be used for avoiding the introduction of material or electrode thickness change, thereby greatly reducing the preparation difficulty and the process cost.

The acoustic surface wave device realized based on the structure, such as a resonator and a filter, has reduced clutter signals in a passband, improved performances in all aspects, higher Q value and smaller insertion loss.

According to a second aspect of the present application, referring to fig. 7, the present disclosure provides a resonator. The resonator comprises a piezoelectric substrate 6 and an interdigital transducer 10, the interdigital transducer 10 being provided on the piezoelectric substrate 6.

It will be appreciated that the interdigital transducer 10 is provided on the piezoelectric substrate 6, and that the interdigital transducer 10 can excite both surface acoustic waves propagating along the x-direction and transverse modes propagating along the length of the first electrode finger 3.

By providing the reflecting assembly 5, the reflecting assembly 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, reducing the leakage of the acoustic surface wave energy. Meanwhile, the connecting line of the connecting 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 included angle between the propagation direction of the acoustic surface wave excited by the interdigital transducer 10 and the connecting line is larger than 0 degrees, and the symmetry of boundary conditions in the length direction of the first electrode finger 3 can be broken. That is, the arrangement of the first electrode finger 3 and the second electrode finger 4 and the arrangement of the reflecting component 5 can effectively inhibit the transverse mode excited by the surface acoustic wave, reduce the loss of the resonator, reduce the fluctuation of the Q value, avoid the adverse effects of the fluctuation of the pass band of the filter, the increase of the insertion loss and the like, and greatly reduce the preparation difficulty and the process cost without introducing the change of materials or electrode thickness.

In some examples, piezoelectric substrate 6 may be a single-layer or multi-layer film structure substrate formed of piezoelectric single crystal, piezoelectric ceramic, or other piezoelectric material. The piezoelectric material may be quartz, liNbO3, liTaO3, alN, scAlN, znO or other materials with piezoelectric properties.

In some embodiments, referring to fig. 7, 8, 9, 10 and 11, the resonator further comprises at least two reflective grating structures 7, at least two reflective grating structures 7 and an interdigital transducer 10 are provided on the same side of the piezoelectric substrate 6, the interdigital transducer 10 being located between the two reflective grating structures 7.

It can be appreciated that the reflective grating structure 7 is used for surface acoustic wave transmission, and the reflective component 5 is arranged on the interdigital transducer 10, so that the resonator can effectively suppress clutter in a passband generated by a transverse mode.

In some embodiments, referring to fig. 8, the reflective grid structure 7 includes a third bus bar 71, a fourth bus bar 72, and a connection bar 73, the connection bar 73 connecting the third bus bar 71 and the fourth bus bar 72.

It is understood that the third bus bar 71 and the fourth bus bar 72 are connected by the connection bar 73 to form the reflective gate structure 7.

In some embodiments, referring to fig. 8, the reflective grating structure 7 further includes a third electrode finger 74, a fourth electrode finger 75, and a second lateral dummy finger 76, the third electrode finger 74 being connected to the third bus bar 71, the fourth electrode finger 75 being connected to the fourth bus bar 72, at least one of the third electrode finger 74 and the fourth electrode finger 75 being connected to the second lateral dummy finger 76.

It will be appreciated that the second transverse artificial finger 76 may reflect the transverse mode such that the reflective grating structure 7 may also suppress noise in the passband generated by the transverse mode to improve the effect of suppressing noise in the passband.

Fig. 13 shows simulation results of admittance curves of the embodiment of fig. 7 and the comparative example of fig. 10. It can be seen that in the comparative example of fig. 10, the transverse mode causes passband ripple in the dashed box, whereas in the embodiment of fig. 7, the addition of the reflecting element 5 effectively suppresses passband clutter generated by the transverse mode.

Fig. 14 shows simulation results of admittance curves of the embodiment of fig. 9 and the comparative example of fig. 10. It can be seen that in the embodiment of fig. 7, the addition of the reflecting element 5 effectively suppresses spurious components in the passband generated by the transverse mode.

According to a third aspect of the present disclosure, a filter is provided. The filter comprises the resonator described above.

It will be appreciated that by providing the reflecting assembly 5, the reflecting assembly 5 may reflect transverse modes excited along the length of the first electrode finger 3 and/or the length of the second electrode finger 4, reducing leakage of acoustic surface wave energy. Meanwhile, the connecting line of the connecting 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 included angle between the propagation direction of the acoustic surface wave excited by the interdigital transducer 10 and the connecting line is larger than 0 degrees, and the symmetry of boundary conditions in the length direction of the first electrode finger 3 can be broken. That is, the arrangement of the first electrode finger 3 and the second electrode finger 4 and the arrangement of the reflecting component 5 can effectively inhibit the transverse mode excited by the surface acoustic wave, reduce the loss of the resonator, reduce the fluctuation of the Q value, avoid the adverse effects of the fluctuation of the pass band of the filter, the increase of the insertion loss and the like, and greatly reduce the preparation difficulty and the process cost without introducing the change of materials or electrode thickness.

According to a fourth aspect of the present disclosure, a vehicle is provided. The vehicle comprises the filter.

It will be appreciated that by providing the reflecting assembly 5, the reflecting assembly 5 may reflect transverse modes excited along the length of the first electrode finger 3 and/or the length of the second electrode finger 4, reducing leakage of acoustic surface wave energy. Meanwhile, the connecting line of the connecting 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 included angle between the propagation direction of the acoustic surface wave excited by the interdigital transducer 10 and the connecting line is larger than 0 degrees, and the symmetry of boundary conditions in the length direction of the first electrode finger 3 can be broken. That is, the arrangement of the first electrode finger 3 and the second electrode finger 4 and the arrangement of the reflecting component 5 can effectively inhibit the transverse mode excited by the surface acoustic wave, reduce the loss of the resonator, reduce the fluctuation of the Q value, avoid the adverse effects of the fluctuation of the pass band of the filter, the increase of the insertion loss and the like, and greatly reduce the preparation difficulty and the process cost without introducing the change of materials or electrode thickness.

In the description of the present application, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

The embodiments, the implementation modes and the related technical features of the application can be mutually combined and replaced under the condition of no conflict.

The foregoing is only a preferred embodiment of the present application, and is not intended to limit the present application in any way, but any simple modification, equivalent variation and modification made to the above embodiment according to the technical matter of the present application still fall within the scope of the technical solution of the present application.

Claims (13)

1. An interdigital transducer comprising a first bus bar, a second bus bar, a first electrode finger and a second electrode finger, the first electrode finger being connected to the first bus bar, the second electrode finger being connected to the second bus bar;

The interdigital transducer further comprises a reflecting component, and at least one of the first electrode finger and the second electrode finger is connected with the reflecting component;

And the connecting line of the connecting point of the first electrode finger strip and the first bus bar is oblique to the first electrode finger strip.

2. The interdigital transducer of claim 1 wherein the reflective component comprises a first transverse artificial finger, at least a portion of which extends parallel to the connecting line and/or perpendicular to the length of the first electrode finger.

3. The interdigital transducer of claim 2, wherein the interdigital transducer comprises at least two of the first electrode fingers and at least two of the second electrode fingers, the first electrode fingers and the second electrode fingers being alternately distributed, wherein,

The first lateral dummy finger at least one of the first electrode fingers being spaced apart from an adjacent one of the first electrode fingers, and/or,

The first lateral dummy finger at least one of the second electrode fingers being spaced apart from an adjacent one of the second electrode fingers, and/or,

At least one of the first lateral dummy fingers at the first electrode finger, connected to an adjacent first electrode finger, and/or,

The first lateral dummy finger at least one of the second electrode fingers is connected to an adjacent one of the second electrode fingers.

4. The interdigital transducer of claim 3, wherein the reflective component comprises a longitudinal artificial finger and at least two of the first transverse artificial fingers, the first transverse artificial fingers being connected to the longitudinal artificial fingers to form at least two reflective gratings.

5. The interdigital transducer of claim 2 wherein the first transverse artificial finger has a metallization ratio of between 10% and 90%.

6. The interdigital transducer of any one of claims 1-5, wherein the connecting line forms an angle of between-75 ° and +75° with the first electrode finger.

7. The interdigital transducer of any one of claims 1 to 5 wherein the first electrode finger has a metallization ratio of between 10% and 90%, and/or,

The metallization rate of the second electrode finger is between 10% and 90%.

8. A resonator comprising a piezoelectric substrate and an interdigital transducer according to any one of claims 1 to 7, wherein the interdigital transducer is provided on the piezoelectric substrate.

9. The resonator of claim 8, further comprising at least two reflective grating structures, at least two of the reflective grating structures and the interdigital transducer being disposed on the same side of the piezoelectric substrate, the interdigital transducer being disposed between two of the reflective grating structures.

10. The resonator of claim 9, wherein the reflective gate structure comprises a third bus bar, a fourth bus bar, and a connection bar connecting the third bus bar and the fourth bus bar.

11. The resonator of claim 10, wherein the reflective-gate structure further comprises a third electrode finger, a fourth electrode finger, and a second lateral dummy finger, the third electrode finger being connected to the third bus bar, the fourth electrode finger being connected to the fourth bus bar, at least one of the third electrode finger and the fourth electrode finger being connected to the second lateral dummy finger.

12. A filter comprising a resonator as claimed in any one of claims 8 to 11.

13. A vehicle comprising a filter according to claim 12.