WO2024098786A9 - Surface acoustic wave resonator, filter, and electronic device - Google Patents

Abstract

Embodiments of the present application relate to the technical field of communication devices, and specifically relate to a surface acoustic wave resonator, a filter, and an electronic device. The embodiments of the present application aim to solve the problem of the volume of the electronic device being relative large due to the area of a surface of a filter used for propagating acoustic waves being relatively large. With regard to the surface acoustic wave resonator, the filter, and the electronic device provided in the present embodiment, a first blocking structure comprises a first blocking unit and a second blocking unit, the first blocking unit is located between the second blocking unit and a transducer, and compared to blocking acoustic wave transmission by means of a forbidden band effect of a first reflective grating and a second reflective grating, there is no need to provide a plurality of grids, thereby reducing the area of a surface of the surface acoustic wave resonator used for propagating acoustic waves, and further reducing the volumes of the surface acoustic wave resonator, the filter, and the electronic device.

Description

Surface acoustic wave resonator, filter and electronic device

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on November 9, 2022, with application number 202211398955.8 and application name “Surface Acoustic Wave Resonator, Filter and Electronic Device”, all contents of which are incorporated by reference in this application.

Technical Field

The embodiments of the present application relate to the technical field of communication equipment, and specifically to a surface acoustic wave resonator, a filter, and an electronic device.

Background technique

Electronic devices (such as mobile phones, tablet computers, televisions, etc.) are generally provided with filters to filter signals through the filters, thereby improving communication quality. However, in the related art, the surface area of the filter used to propagate sound waves is large, resulting in a larger volume of the electronic device.

Summary of the invention

The embodiments of the present application provide a surface acoustic wave resonator, a filter and an electronic device, which can reduce the surface area of the surface acoustic wave resonator used to propagate sound waves, thereby reducing the volume of the surface acoustic wave resonator, the filter and the electronic device.

In a first aspect, an embodiment of the present application provides a surface acoustic wave resonator, comprising a piezoelectric material layer, a transducer, and a first blocking structure, wherein the transducer and the first blocking structure are arranged on a preset surface of the piezoelectric material layer; the first blocking structure is used to prevent the target sound wave from propagating in a direction away from the transducer; the first blocking structure comprises: a first blocking unit and a second blocking unit, the first blocking unit and the second blocking unit are both located on the preset surface, and the first blocking unit and the second blocking unit are both located on one side of the transducer along the sound wave transmission direction; the first blocking unit is located between the second blocking unit and the transducer.

Through the above arrangement, the first blocking structure is arranged on one side of the transducer along the direction of sound wave transmission, the first blocking structure includes a first blocking unit and a second blocking unit, the first blocking unit is located between the second blocking unit and the transducer, and the acoustic impedance of the second blocking unit is different from the acoustic impedance of the first blocking unit, so as to adjust the spatial distribution characteristics of the acoustic impedance of the transducer close to one end of the first blocking structure, so that the effective acoustic impedance of the preset surface of the piezoelectric material layer changes from high to low, or from low to high, thereby limiting the propagation of the target sound wave, and then limiting the energy to the area where the transducer is located, so as to achieve the blocking of the target sound wave. Compared with preventing the transmission of sound waves through the bandgap effect of the first reflection grating and the second reflection grating, the width of the surface acoustic wave resonator along the direction of sound wave transmission is reduced without setting multiple grids, thereby reducing the area of the surface for propagating sound waves, thereby reducing the volume of the surface acoustic wave resonator, the filter and the electronic device.

In some embodiments that may include the above embodiments, the first blocking structure further includes a third blocking unit and a fourth blocking unit, the fourth blocking unit is arranged on a side of the second blocking unit away from the transducer, and the third blocking unit is located between the fourth blocking unit and the second blocking unit. The acoustic impedance of the third blocking unit is equal to or substantially equal to the acoustic impedance of the first blocking unit, and the acoustic impedance of the fourth blocking unit is equal to or substantially equal to the acoustic impedance of the second blocking unit.

Such an arrangement can further suppress the propagation of the target sound wave, so as to further limit the energy excited by the transducer to the area near the transducer.

In some embodiments that may include the above embodiments, the first blocking unit includes a first grid bar, the first grid bar extends on a preset surface in a direction perpendicular to the direction of sound wave transmission, and the second blocking unit may include a second grid bar, the second grid bar extends on a preset surface in a direction perpendicular to the direction of sound wave transmission; the extension length of the first grid bar may be equal to the length of the transducer in the direction perpendicular to the direction of sound wave transmission, or the extension length of the first grid bar is greater than the length of the transducer in the direction perpendicular to the direction of sound wave transmission; the extension length of the second grid bar may be equal to the length of the transducer in the direction perpendicular to the direction of sound wave transmission, or the extension length of the second grid bar is greater than the length of the transducer in the direction perpendicular to the direction of sound wave transmission. That is to say, along the direction perpendicular to the direction of sound wave transmission, the first grid bar and the second grid bar completely cover the transducer to avoid partial exposure of the transducer, resulting in leakage of the target sound wave, thereby improving the energy limiting effect on the target sound wave.

The third blocking unit includes a third grid bar, which extends on the preset surface in a direction perpendicular to the sound wave transmission direction. The fourth blocking unit may include a fourth grid bar, which extends on the preset surface in a direction perpendicular to the sound wave transmission direction. The extension length of the third grid bar may be equal to the length of the transducer along the direction perpendicular to the sound wave transmission direction, or the extension length of the third grid bar is greater than the length of the transducer along the direction perpendicular to the sound wave transmission direction. The extension length of the fourth grid bar may be equal to the length of the transducer along the direction perpendicular to the sound wave transmission direction. The length of the third and fourth grating bars is equal to that of the transducer, or the extension length of the fourth grating bar is greater than the length of the transducer along the direction perpendicular to the sound wave transmission direction. That is, along the direction perpendicular to the sound wave transmission direction, the third and fourth grating bars completely cover the transducer to further improve the energy limiting effect on the target sound wave.

In some embodiments that may include the above embodiments, the width of the first grid bar along the direction parallel to the sound wave transmission direction is d ₁ , the width of the second grid bar along the direction parallel to the sound wave transmission direction is d ₂ , the width of the third grid bar along the direction parallel to the sound wave transmission direction is d ₃ , and the width of the fourth grid bar along the direction parallel to the sound wave transmission direction is d ₄ , and d ₁ , d ₂ , d ₃ , and d ₄ satisfy the following relationship:
0.1λ _ss <d ₁ <λ _l
0.1λ _ss <d ₂ <λ _l
0.1λss _{< d3} < _λl
0.1λ _ss <d ₄ <λ _l

Wherein: λ _ss is the wavelength of the slow shear body wave of the piezoelectric material layer, satisfying λ _ss =v _ss / _fr ; λ _l is the wavelength of the longitudinal compression vibration body wave of the piezoelectric material layer, satisfying λ _l =v _l / _fr ; v _ss is the wave velocity of the slow shear body wave of the piezoelectric material layer, v _l is the wave velocity of the longitudinal compression vibration body wave, and f _r is the resonant frequency of the surface acoustic wave resonator.

Through the above-mentioned arrangement, while ensuring that the first blocking structure has a good blocking effect on the target sound wave, the widths of the first grating, the second grating, the third grating and the fourth grating can be smaller along the direction parallel to the sound wave transmission direction, so as to further reduce the width of the surface acoustic wave resonator along the sound wave transmission direction, thereby further reducing the surface area of the surface acoustic wave resonator used to propagate sound waves, and further reducing the volume of the surface acoustic wave resonator, the filter and the electronic device.

In some embodiments that may include the above embodiments, the acoustic impedance of the first blocking unit is less than the acoustic impedance of the second blocking unit, and the acoustic impedance of the first blocking unit is less than or equal to the acoustic impedance of the transducer electrode. In this way, the spatial distribution characteristics of the acoustic impedance of the transducer near one end of the first blocking structure can be adjusted, so that the effective acoustic impedance of the preset surface of the piezoelectric material layer changes from low to high, thereby limiting the propagation of the target sound wave, and then limiting the energy to the area where the transducer is located, thereby achieving the blocking of the target sound wave.

In some embodiments that may include the above embodiments, the first blocking unit includes an air wall, that is, the position corresponding to the first blocking unit is a gap. Such a setting simplifies the difficulty of manufacturing the surface acoustic wave resonator and also reduces the quality and manufacturing cost of the surface acoustic wave resonator.

In some embodiments that may include the above embodiments, the material of the first blocking unit may further include at least one of silicon dioxide (SiO ₂ ) and aluminum (Al). Compared with the first blocking unit being an air wall, the degree of freedom of adjusting the acoustic impedance can be increased, thereby improving the performance of the surface acoustic wave resonator. At the same time, the influence of the external air on the acoustic impedance of the first blocking unit can be avoided, thereby improving the accuracy of the filter.

In some embodiments that may include the above embodiments, the material of the second blocking unit may include at least one of hafnium oxide (HfO ₂ ), hafnium nitride (HfN), tungsten nitride (WN), tungsten oxide (WO ₃ ), tantalum oxide (Ta ₂ O ₅ ), platinum (Pt), tantalum (Ta), tungsten (W), and iridium (Tr). In this way, the second blocking unit has a higher acoustic impedance, thereby improving the energy limiting effect of the first blocking structure on the target sound wave.

In some embodiments that may include the above-mentioned embodiments, the acoustic impedance of the first blocking unit is greater than the acoustic impedance of the second blocking unit; with such a configuration, the spatial distribution characteristics of the acoustic impedance of the transducer near one end of the first blocking structure can be adjusted, so that the effective acoustic impedance of the preset surface of the piezoelectric material layer changes from high to low, thereby limiting the propagation of the target sound wave, and then limiting the energy to the area where the transducer is located, thereby blocking the target sound wave.

In some embodiments that may include the above embodiments, the surface acoustic wave resonator further includes a second blocking structure, the second blocking structure is located on the preset surface, and the second blocking structure is arranged on the other side of the transducer along the direction of sound wave transmission, and the second blocking structure is used to prevent the sound wave from propagating in a direction away from the transducer. In this way, the target sound wave is limited to the area where the transducer is located by the first blocking structure and the second blocking structure, further improving the communication quality.

In some embodiments that may include the above embodiments, the surface acoustic wave resonator further includes a functional layer and a substrate layer, the functional layer is arranged facing the surface of the piezoelectric material layer opposite to the preset surface, and the substrate layer is arranged on the side of the functional layer away from the piezoelectric material layer; that is, the functional layer is arranged between the substrate layer and the piezoelectric material layer. In this arrangement, the substrate layer can provide support for the functional layer and the piezoelectric material layer to ensure the overall strength of the surface acoustic wave resonator.

In some embodiments, which may include the above embodiments, the frequency temperature coefficient of the functional layer is positive, that is, at temperature When the temperature rises, the resonant frequency of the functional layer shifts to high frequency; the frequency temperature coefficient of the piezoelectric material layer is negative, that is, when the temperature rises, the resonant frequency of the piezoelectric material layer shifts to low frequency. In this way, the piezoelectric material layer and the functional layer compensate each other, which can prevent the resonant frequency of the surface acoustic wave resonator from shifting to low frequency or high frequency, thereby improving the stability of the surface acoustic wave resonator.

In some embodiments that may include the above embodiments, the surface acoustic wave resonator may further include a transition layer, which is disposed between the functional layer and the substrate layer. The material of the transition layer is reasonably selected according to the materials of the functional layer and the substrate layer, so that the transition layer and the functional layer, and the transition layer and the substrate layer have a greater connection force, thereby improving the connection force between the substrate layer and the functional layer, that is, improving the process compatibility between different materials.

In some embodiments that may include the above embodiments, the surface acoustic wave resonator may further include a covering layer, the covering layer covers the preset surface of the piezoelectric material layer, and the covering layer covers the transducer and the first blocking structure, that is, the transducer and the first blocking structure are both located in the covering layer. In this way, the covering layer can prevent foreign objects from contacting the transducer and the first blocking structure, thereby protecting the transducer and the first blocking structure, and the covering layer can also seal the transducer and the first blocking structure.

In some embodiments that may include the above-mentioned embodiments, the frequency temperature coefficient of the covering layer is a positive value, that is, the resonant frequency of the covering layer shifts toward high frequency when the temperature rises; the frequency temperature coefficient of the piezoelectric material layer is a negative value, that is, the resonant frequency of the piezoelectric material layer shifts toward low frequency when the temperature rises; in this arrangement, the piezoelectric material layer and the covering layer compensate each other, which can prevent the resonant frequency of the surface acoustic wave resonator from shifting toward low frequency or high frequency, thereby improving the stability of the surface acoustic wave resonator.

In a second aspect, an embodiment of the present application further provides a filter, comprising: a housing, and the surface acoustic wave resonator as described above, wherein the surface acoustic wave resonator is arranged on the housing.

Through the above arrangement, the first blocking structure in the surface acoustic wave resonator is arranged on one side of the transducer along the direction of acoustic wave transmission, the first blocking structure includes a first blocking unit and a second blocking unit, the first blocking unit is located between the second blocking unit and the transducer, and the acoustic impedance of the second blocking unit is different from the acoustic impedance of the first blocking unit, so as to adjust the spatial distribution characteristics of the acoustic impedance of the transducer close to one end of the first blocking structure, so that the effective acoustic impedance of the preset surface of the piezoelectric material layer changes from high to low, or from low to high, thereby limiting the propagation of the target acoustic wave, and then limiting the energy to the area where the transducer is located, limiting the propagation of the target acoustic wave. Compared with limiting the transmission of acoustic waves through the bandgap effect of the first reflection grid and the second reflection grid, there is no need to set multiple grids, which reduces the width of the surface acoustic wave resonator along the direction of acoustic wave transmission, thereby reducing the area of the surface used to propagate acoustic waves, and thereby reducing the volume of the surface acoustic wave resonator, the filter and the electronic device.

In a third aspect, an embodiment of the present application further provides an electronic device, comprising: a communication circuit, and the filter as described above, wherein the communication circuit is electrically connected to the filter.

Through the above arrangement, in the surface acoustic wave resonator of the filter, the first blocking structure is arranged on one side of the transducer along the direction of acoustic wave transmission, the first blocking structure includes a first blocking unit and a second blocking unit, the first blocking unit is located between the second blocking unit and the transducer, and the acoustic impedance of the second blocking unit is different from the acoustic impedance of the first blocking unit, so as to adjust the spatial distribution characteristics of the acoustic impedance of the transducer close to one end of the first blocking structure, so that the effective acoustic impedance of the preset surface of the piezoelectric material layer changes from high to low, or from low to high, thereby limiting the propagation of the target acoustic wave, and further limiting the energy to the area where the transducer is located. Compared with preventing the transmission of acoustic waves through the bandgap effect of the first reflection grating and the second reflection grating, there is no need to set multiple grids, which reduces the width of the surface acoustic wave resonator along the direction of acoustic wave transmission, thereby reducing the area of the surface for propagating acoustic waves, and further reducing the volume of the surface acoustic wave resonator, the filter and the electronic device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a filter provided in an embodiment of the present application;

FIG2 is a cross-sectional view of a surface acoustic wave resonator provided by the present application;

FIG3 is a top view of the surface acoustic wave resonator shown in FIG2 ;

FIG4 is a cross-sectional view 1 of a resonator in the related art;

FIG5 is a top view of the resonator shown in FIG4 ;

FIG6 is a diagram showing the relationship between the resonator admittance and the frequency when the first reflection grating and the second reflection grating are not provided in the related art;

FIG7 is a diagram showing the relationship between the resonator admittance and the frequency when the first reflection grating and the second reflection grating are provided in the related art;

FIG8 is a graph showing the relationship between the quality factor and the frequency of the resonator when the first reflection grating and the second reflection grating are not provided in the related art;

FIG9 is a diagram showing the relationship between the resonator quality factor and the frequency when the first reflection grating and the second reflection grating are provided in the related art;

FIG10 is a second cross-sectional view of a surface acoustic wave resonator provided by an embodiment of the present application;

FIG11 is a top view of the surface acoustic wave resonator shown in FIG10;

FIG12 is a third cross-sectional view of a surface acoustic wave resonator provided by the present application;

FIG13 is a top view of the surface acoustic wave resonator shown in FIG12;

FIG14 is a fourth cross-sectional view of a surface acoustic wave resonator provided by an embodiment of the present application;

FIG15 is a graph showing the relationship between the admittance and frequency of a surface acoustic wave resonator provided by the present application;

FIG16 is a graph showing the relationship between the quality factor and frequency of a surface acoustic wave resonator provided by the present application;

FIG17 is a fifth cross-sectional view of a surface acoustic wave resonator provided by an embodiment of the present application;

FIG18 is a sixth cross-sectional view of a surface acoustic wave resonator provided by an embodiment of the present application;

FIG. 19 is a seventh cross-sectional view of the surface acoustic wave resonator provided in accordance with an embodiment of the present application.

Explanation of the figure markings: 100: surface acoustic wave resonator; 101: first reflection grating; 102: second reflection grating; 103: grid; 104: first bus bar; 105: second bus bar; 110: piezoelectric material layer; 111: preset surface; 120: transducer; 121: first electrode; 122: second electrode; 123: first electrode bus bar; 124: second electrode bus bar; 130: first blocking structure; 131: first blocking unit; 132: second blocking unit; 133: third blocking unit; 134: fourth blocking unit; 140: second blocking structure; 150: functional layer; 170: transition layer; 180: covering layer.

Detailed ways

In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

The embodiment of the present application provides an electronic device, which may include a mobile phone, a tablet computer, a television, etc. Referring to FIG1 , the electronic device includes a filter and a communication circuit electrically connected thereto, and under the control of the communication circuit, the filter can perform an electric signal-acoustic signal (sound wave)-electric signal conversion, and in the process of conversion, the sound wave is filtered out to achieve filtering, thereby improving the communication quality of the electronic device.

The filter may include a plurality of surface acoustic wave resonators 100, wherein the plurality of surface acoustic wave resonators 100 include: a first surface acoustic wave resonator 10, a second surface acoustic wave resonator 20, a third surface acoustic wave resonator 30, a fourth surface acoustic wave resonator 40, a fifth surface acoustic wave resonator 50, a sixth surface acoustic wave resonator 60, and a seventh surface acoustic wave resonator 70, wherein the first surface acoustic wave resonator 10, the second surface acoustic wave resonator 20, the third surface acoustic wave resonator 30, the fourth surface acoustic wave resonator 40 are connected in series, and the fifth surface acoustic wave resonator 50 is connected in series. One end of the first surface acoustic wave resonator 10 is connected to one end of the second surface acoustic wave resonator 20, the other end of the fifth surface acoustic wave resonator 50 is grounded, one end of the sixth surface acoustic wave resonator 60 is connected to one end of the second surface acoustic wave resonator 20 for connecting to the third surface acoustic wave resonator 30, the other end of the sixth surface acoustic wave resonator 60 is grounded, one end of the seventh surface acoustic wave resonator 70 is connected to one end of the third surface acoustic wave resonator 30 for connecting to the fourth surface acoustic wave resonator 40, and the other end of the seventh surface acoustic wave resonator 70 is grounded.

It is worth noting that the filter shown in Figure 1 is only one structure of the filter, which includes 7 surface acoustic wave resonators, but the filter structure in this embodiment is not limited to this. The number of surface acoustic wave resonators included in the filter can also be 5, 6, 8, 9, etc., and the surface acoustic wave resonators are connected to achieve filtering; this embodiment also does not limit the connection between the surface acoustic wave resonators.

The surface acoustic wave resonator 100 is used to receive electrical signals and generate sound waves. FIG2 is a cross-sectional view of the surface acoustic wave resonator provided by the present application. Referring to FIG2, the surface acoustic wave resonator 100 includes a piezoelectric material layer 110 and a transducer 120, wherein the piezoelectric material layer 110 is in a plate shape, and the transducer 120 is arranged on a preset surface 111 of the piezoelectric material layer 110 with a larger area; when receiving an electrical signal, the transducer 120 drives the piezoelectric material layer 110 to vibrate to generate a sound wave, which is transmitted along the preset surface 111, thereby converting the electrical signal into a mechanical vibration signal (sound wave).

The present embodiment does not limit the material of the piezoelectric material layer 110, as long as the piezoelectric material layer 110 can vibrate under the drive of the transducer 120 to generate sound waves; illustratively, the material of the piezoelectric material layer 110 may include: piezoelectric crystals (such as lithium niobate ( _LiNbO3 ), lithium tantalate ( _LiTaO3 ), quartz (Quartz), etc.), piezoelectric films (aluminum nitride (AlN), _scandium -doped aluminum nitride (AlScN)), piezoelectric ceramics (such as lead niobate ( _PbNb2O6 ), lead zirconate titanate (PZT), etc.).

In this embodiment, the transducer 120 drives the piezoelectric material layer 110 to vibrate under the action of the electrical signal. For example, the transducer 120 may include an interdigital transducer (IDT). FIG. 3 is a top view of the surface acoustic wave resonator shown in FIG. View, please refer to Figure 3, the transducer 120 may include a plurality of first electrodes 121 and a plurality of second electrodes 122, the plurality of first electrodes 121 and the plurality of second electrodes 122 are all attached to the preset surface 111, the plurality of first electrodes 121 are arranged in parallel and spaced apart, the plurality of second electrodes 122 are arranged in parallel and spaced apart, and the first electrode 121 is parallel to the second electrode 122, and a second electrode 122 is arranged between two adjacent first electrodes 121. The transducer 120 also includes a first electrode bus bar 123 and a second electrode bus bar 124, both of which are attached to the preset surface 111, the first electrode bus bar 123 is perpendicular to the first electrode 121, and the first electrode bus bar 123 is connected to one end of each first electrode 121 (the top end of the orientation shown in FIG. 3); the second electrode bus bar 124 is perpendicular to the second electrode 122, and the second electrode bus bar 124 is connected to one end of each second electrode 122 (the bottom end of the orientation shown in FIG. 3), the first electrode bus bar 123 and the second electrode bus bar 124 are arranged opposite to each other, that is, each first electrode 121 and each second electrode 122 are located between the first electrode bus bar 123 and the second electrode bus bar 124.

During operation, power can be supplied to each first electrode 121 through the first electrode bus 123, and power can be supplied to the second electrode 122 through the second electrode bus 124, thereby causing the piezoelectric material layer 110 shown in FIG. 2 to vibrate to generate sound waves; the sound waves propagate near the preset surface 111 in a direction parallel to the preset surface 111 and perpendicular to the first electrode 121 (the X direction in the orientation shown in FIG. 3 ).

It is worth noting that this example does not limit the structure of the transducer 120 , and the transducer 120 may also have other structures as long as it can drive the piezoelectric material layer 110 to vibrate under the action of an electrical signal and thus form a sound wave.

Continuing with reference to FIG. 2 , in this embodiment, the surface acoustic wave resonator 100 further includes a first blocking structure 130 , which is located on the preset surface 111 , and the first blocking structure 130 is disposed on one side of the transducer 120 along the sound wave transmission direction; it can be understood that the sound wave transmission direction is the transmission direction of the sound wave generated by the transducer 120 driving the piezoelectric material layer 110 to vibrate (the X direction in the orientation shown in FIG. 2 ), and in the implementation mode in which the transducer 120 is an interdigital transducer, the sound wave transmission direction is a direction parallel to the preset surface 111 and perpendicular to the first electrode 121 .

The first blocking structure 130 is used to prevent the target sound wave from propagating in a direction away from the transducer 120 (the X direction of the orientation shown in FIG. 2 ), that is, the target sound wave is difficult to pass through the first blocking structure 130, so as to limit the target sound wave to the area where the transducer 120 is located. The target sound wave may be a sound wave with a predetermined frequency band, and the sound wave of the predetermined frequency band is the sound wave required in the communication process. It can be understood that a reasonable selection of the target sound wave can meet different communication needs and improve the communication quality.

2 , in the above implementation, the first blocking structure 130 may include: a first blocking unit 131 and a second blocking unit 132, both of which are located on the preset surface 111, and both of which are located on one side of the transducer 120 along the direction of sound wave transmission; the first blocking unit 131 is located between the second blocking unit 132 and the transducer 120. The acoustic impedances of the first blocking unit 131 and the second blocking unit 132 are different, so as to adjust the spatial distribution characteristics of the acoustic impedance of the end of the transducer 120 close to the first blocking structure 130, so that the effective acoustic impedance of the preset surface 111 of the piezoelectric material layer 110 changes from high to low, or from low to high, thereby limiting the propagation of the target sound wave, and further limiting the energy to the area where the transducer 120 is located, so as to achieve the energy limiting effect on the target sound wave.

It is understandable that the acoustic impedance of the first blocking unit 131 can be less than the acoustic impedance of the second blocking unit 132, and the acoustic impedance of the first blocking unit 131 is less than or equal to the acoustic impedance of the electrodes of the transducer 120 (the first electrode 121 and the second electrode 122 in FIG. 3 ). In this way, the spatial distribution characteristics of the acoustic impedance of the end of the transducer 120 close to the first blocking structure 130 can be adjusted, so that the effective acoustic impedance of the preset surface 111 of the piezoelectric material layer 110 changes from low to high, thereby limiting the propagation of the target sound wave, and then limiting the energy to the area where the transducer 120 is located, thereby achieving the blocking of the target sound wave.

Of course, the acoustic impedance of the first blocking unit 131 can be greater than the acoustic impedance of the second blocking unit 132; with such a setting, the spatial distribution characteristics of the acoustic impedance of the end of the transducer 120 close to the first blocking structure 130 can be adjusted, so that the effective acoustic impedance of the preset surface 111 of the piezoelectric material layer 110 changes from high to low, thereby limiting the propagation of the target sound wave, and then limiting the energy to the area where the transducer 120 is located, thereby achieving the energy limitation effect on the target sound wave.

Figure 4 is a cross-sectional view 1 of a resonator in the related art. Please refer to Figure 4. In the related art, the resonator includes a piezoelectric material layer 110 and a transducer 120, a first reflection grating 101 and a second reflection grating 102 arranged on the piezoelectric material layer 110. The transducer 120 is arranged on a preset surface 111 of the piezoelectric material layer 110. Under the action of an electrical signal, the transducer 120 drives the piezoelectric material layer 110 to vibrate, thereby generating sound waves, and the sound waves propagate along the preset surface 111.

FIG5 is a top view of the resonator shown in FIG4. Referring to FIG5, the first reflection grating 101 and the second reflection grating 102 are used as reflection gratings and are both arranged on the preset surface 111 shown in FIG4. The first reflection grating 101 is located on one side of the transducer 120 along the sound wave transmission direction (X direction), and the second reflection grating 102 is located on the other side of the transducer 120 along the sound wave transmission direction. The invention comprises a plurality of grids 103 arranged in parallel and at intervals, the extension direction of the grids 103 is perpendicular to the transmission direction of the sound wave (Y direction), one end of each grid 103 is connected to the first bus bar 104, and the other end of each grid 103 is connected to the second bus bar 105. Each grid 103, the first bus bar 104 and the second bus bar 105 can be a metal sheet, and each grid 103, the first bus bar 104 and the second bus bar 105 are an integral structure. Due to the bandgap effect, it is difficult for the target frequency sound wave generated by the transducer 120 to pass through the first reflection grid 101, that is, the first reflection grid 101 limits the energy excited by the transducer 120 to the area where the transducer 120 is located. The structure of the second reflection grid 102 is substantially the same as that of the first reflection grid 101, and the target sound wave generated by the transducer 120 can be limited to the area where the transducer 120 is located through the first reflection grid 101 and the second reflection grid 102.

Please refer to Figures 6 and 7, wherein Figure 6 is a diagram showing the relationship between the resonator admittance and frequency when the first reflection grating 101 and the second reflection grating 102 shown in Figure 5 are not set, and Figure 7 is a diagram showing the relationship between the resonator admittance and frequency when the first reflection grating 101 and the second reflection grating 102 (as shown in Figures 4 and 5) are set. It can be seen from Figures 6 and 7 that the resonance point of the resonator is 682 MHz, and the anti-resonance point of the resonator is 721 MHz. FIG8 is a graph showing the relationship between the quality factor and the frequency of the resonator when the first reflection grating 101 and the second reflection grating 102 are not provided, and FIG9 is a graph showing the relationship between the quality factor and the frequency of the resonator when the first reflection grating 101 and the second reflection grating 102 are provided (as shown in FIG4 and FIG5 ). By comparing FIG8 and FIG9 , it can be seen that between the resonance point and the anti-resonance point, the quality factor of the resonator without the first reflection grating 101 and the second reflection grating 102 is lower than the quality factor of the resonator with the first reflection grating 101 and the second reflection grating 102 provided. It can be seen that the energy limiting effect of the first reflection grating 101 and the second reflection grating 102 can significantly improve the quality factor of the resonator.

In the related art, in order to ensure that the first reflection grating 101 and the second reflection grating 102 shown in Figure 5 have a higher energy limiting effect, the number of grids 103 of the first reflection grating 101 and the second reflection grating 102 is relatively large (for example, the number of grids 103 is greater than 20), resulting in a larger width of the resonator along the direction of sound wave transmission, resulting in a larger area of the filter and a larger volume of the electronic device.

The surface acoustic wave resonator 100 provided in the embodiment of the present application is shown in Figure 2. The transducer 120 and the first blocking structure 130 are both arranged on the preset surface 111 of the piezoelectric material layer 110. The first blocking structure 130 is arranged on one side of the transducer 120 along the sound wave transmission direction. The first blocking structure 130 includes a first blocking unit 131 and a second blocking unit 132. The first blocking unit 131 is located between the second blocking unit 132 and the transducer 120. The acoustic impedance of the second blocking unit 132 is different from the acoustic impedance of the first blocking unit 131, so as to adjust the spatial distribution characteristics of the acoustic impedance of the end of the transducer 120 close to the first blocking structure 130, so that the effective acoustic impedance of the preset surface 111 of the piezoelectric material layer 110 changes from high to low, or from low to high, thereby limiting the propagation of the target sound wave, and then limiting the energy to the area where the transducer 120 is located, so as to achieve the blocking of the target sound wave. Compared with preventing the transmission of sound waves through the bandgap effect of the first reflection grating 101 and the second reflection grating 102 (as shown in FIG5 ), there is no need to set up multiple grids 103, which reduces the width of the surface acoustic wave resonator 100 along the direction of sound wave transmission, thereby reducing the area of the surface (preset surface 111) used to propagate sound waves, thereby reducing the volume of the surface acoustic wave resonator 100, the filter and the electronic device.

With the continuous development of communication technology, the communication frequency band is constantly increasing, which also leads to a sharp increase in the number of filters. The increase in the number of filters also leads to the increasingly tight area of RF front-end modules (electronic equipment), thus putting forward higher requirements for the miniaturization of filter size, making the volume of a single filter continuously compressed, and this trend is becoming more and more severe.

In the process of developing filter miniaturization, it is generally achieved by optimizing the packaging structure. For example, the packaging technology of filters has gradually developed from ceramic packaging to chip-size SAW package (Chip Size SAW Package CSSP), and then to die-size SAW package (Die Size SAW Package DSSP) and thin film acoustic package (Thin Film Acoustic Package TFAB). The filter is reduced in size by changing the packaging form, resulting in limited reduction in size.

In the surface acoustic wave resonator 100 (Surface Acoustic Wave SAW) provided in this embodiment, the transducer 120 and the first blocking structure 130 are both arranged on the preset surface 111 of the piezoelectric material layer 110, and the first blocking structure 130 limits the propagation of the target sound wave, and then limits the energy to the area where the transducer 120 is located, thereby blocking the target sound wave; the transducer 120 and the first blocking structure 130 are arranged in the same layer, which can reduce the thickness of the surface acoustic wave resonator 100 along the direction perpendicular to the piezoelectric material layer 110, and at the same time can also reduce the width of the surface acoustic wave resonator 100 along the sound wave transmission direction, which greatly reduces the volume of the surface acoustic wave resonator 100 and the filter.

FIG10 is a second cross-sectional view of a surface acoustic wave resonator provided by the present application, and FIG11 is a top view of the surface acoustic wave resonator shown in FIG10 . Please refer to FIG10 and FIG11 . In some embodiments, the first blocking structure 130 further includes a third blocking unit 133 and a fourth blocking unit 134. The fourth blocking unit 134 is disposed on the side of the second blocking unit 132 away from the transducer 120, and the third blocking unit 133 is located between the fourth blocking unit 134 and the second blocking unit 132. The acoustic impedance of the third blocking unit 133 is equal to or approximately equal to the acoustic impedance of the first blocking unit 131, and the acoustic impedance of the fourth blocking unit 134 is equal to or approximately equal to the acoustic impedance of the second blocking unit 132. With such a configuration, the blocking effect on the target sound waves can be further improved to further reduce the transducer 120. The energy excited by the transducer 120 is confined to the area near the transducer 120.

It can be understood that, in the present embodiment, the first blocking structure 130 may include not only four blocking units, namely the first blocking unit 131, the second blocking unit 132, the third blocking unit 133 and the fourth blocking unit 134; the first blocking structure 130 may also include 5, 6, 7, 8 or other number of blocking units. Taking the first blocking structure 130 including 6 blocking units as an example, the first blocking structure 130 also includes a fifth blocking unit (not shown) and a sixth blocking unit (not shown). The sixth blocking unit is located on the side of the fourth blocking unit 134 away from the transducer 120, and the fifth blocking unit is located between the fourth blocking unit 134 and the sixth blocking unit. The acoustic impedance of the fifth blocking unit is equal to or approximately equal to the acoustic impedance of the first blocking unit 131, and the acoustic impedance of the sixth blocking unit may be equal to or approximately equal to the acoustic impedance of the second blocking unit 132, so as to further improve the blocking effect on the target sound waves.

Continuing to refer to Figures 10 and 11, in the above implementation, the first blocking unit 131 may include a first grid bar, which extends on the preset surface 111 in a direction perpendicular to the sound wave transmission direction (Y direction), and the second blocking unit 132 may include a second grid bar, which extends on the preset surface 111 in a direction perpendicular to the sound wave transmission direction (Y direction); the extension length of the first grid bar may be equal to the length of the transducer 120 along the direction perpendicular to the sound wave transmission direction (Y direction), or the extension length of the first grid bar is greater than the length of the transducer 120 along the direction perpendicular to the sound wave transmission direction (Y direction); the extension length of the second grid bar may be equal to the length of the transducer 120 along the direction perpendicular to the sound wave transmission direction (Y direction), or the extension length of the second grid bar is greater than the length of the transducer 120 along the direction perpendicular to the sound wave transmission direction (Y direction). That is to say, along the direction perpendicular to the sound wave transmission direction (Y direction), the first grid bars and the second grid bars completely cover the transducer 120 to avoid partial exposure of the transducer 120 and resulting leakage of the target sound wave, thereby improving the energy limitation effect on the target sound wave.

Similarly, the third blocking unit 133 may include a third grid bar, which extends on the preset surface 111 in a direction perpendicular to the acoustic wave transmission direction (Y direction), and the fourth blocking unit 134 may include a fourth grid bar, which extends on the preset surface 111 in a direction perpendicular to the acoustic wave transmission direction (Y direction); the extension length of the third grid bar may be equal to the length of the transducer 120 in the direction perpendicular to the acoustic wave transmission direction (Y direction), or the extension length of the third grid bar is greater than the length of the transducer 120 in the direction perpendicular to the acoustic wave transmission direction (Y direction); the extension length of the fourth grid bar may be equal to the length of the transducer 120 in the direction perpendicular to the acoustic wave transmission direction (Y direction), or the extension length of the fourth grid bar is greater than the length of the transducer 120 in the direction perpendicular to the acoustic wave transmission direction (Y direction). That is, along the direction perpendicular to the acoustic wave transmission direction (Y direction), the third grid bar and the fourth grid bar completely cover the transducer 120 to further improve the energy limiting effect on the target acoustic wave.

In some embodiments, the extension lengths of the first bars, the second bars, the third bars, and the fourth bars may be equal, and the extension lengths of the first bars, the second bars, the third bars, and the fourth bars are equal to the width of the transducer 120 along the direction perpendicular to the sound wave transmission direction (Y direction). In this manner, compared with the case where the extension lengths of the first bars, the second bars, the third bars, and the fourth bars are greater than the width of the transducer 120 along the direction perpendicular to the sound wave transmission direction (Y direction), the width of the surface acoustic wave resonator 100 along the direction perpendicular to the sound wave transmission direction (Y direction) can be reduced, thereby further reducing the size of the transducer 120, and further reducing the size of the filter and the electronic device.

In the above implementation, the side of the first bar facing the transducer 120 can contact the transducer 120, the side of the first bar away from the transducer 120 can contact the second bar, the side of the second bar away from the transducer 120 can contact the third bar, and the side of the third bar away from the transducer 120 can contact the fourth bar.

In the implementation method in which the acoustic impedance of the first blocking unit 131 (first grid bar) is less than the acoustic impedance of the second blocking unit 132 (second grid bar), the first blocking unit 131 may include an air wall (as shown in FIG. 10 ), that is, the position corresponding to the first blocking unit 131 is a gap. Such a setting simplifies the manufacturing difficulty of the surface acoustic wave resonator 100, and also reduces the quality and manufacturing cost of the surface acoustic wave resonator 100.

FIG12 is a third cross-sectional view of the surface acoustic wave resonator provided by the present application, and FIG13 is a top view of the surface acoustic wave resonator shown in FIG12. Referring to FIG12 and FIG13, in the implementation mode in which the acoustic impedance of the first blocking unit 131 (first grid bar) is less than the acoustic impedance of the second blocking unit 132 (second grid bar), the material of the first blocking unit 131 may also include at least one of silicon dioxide (SiO ₂ ) and aluminum (Al). Of course, the material of the first blocking unit 131 may also be other materials with lower acoustic impedance than the acoustic impedance of the second blocking unit 132, that is, the first blocking unit 131 is a solid. Compared with the first blocking unit 131 being an air wall, the freedom of adjusting the acoustic impedance can be increased, and the performance of the surface acoustic wave resonator 100 is improved.

In the above implementation, the material of the second blocking unit 132 may include at least one of hafnium oxide (HfO ₂ ), hafnium nitride (HfN), tungsten nitride (WN), tungsten oxide (WO ₃ ), tantalum oxide (Ta ₂ O ₅ ), platinum (Pt), tantalum (Ta), tungsten (W), and iridium (Tr). Of course, the second blocking unit 132 may also be other materials having higher acoustic impedance than the first blocking unit 131. Such a configuration enables the second blocking unit 132 to have a higher acoustic impedance, thereby improving the blocking effect of the first blocking structure 130 on the target sound wave.

FIG14 is a fourth cross-sectional view of the surface acoustic wave resonator 100 provided by the embodiment of the present application. Please refer to FIG13 . In the implementation method in which the acoustic impedance of the first blocking unit 131 (first grid bar) is greater than the acoustic impedance of the second blocking unit 132 (second grid bar), the material of the first blocking unit 131 may include at least one of hafnium oxide (HfO ₂ ), hafnium nitride (HfN), tungsten nitride (WN), tungsten oxide (WO ₃ ), tantalum oxide (Ta ₂ O ₅ ), platinum (Pt), tantalum (Ta), tungsten (W), and iridium (Tr). Of course, the first blocking unit 131 may also be other materials having an acoustic impedance higher than the acoustic impedance of the second blocking unit 132. Accordingly, the second blocking unit 132 may include an air wall, that is, the position corresponding to the second blocking unit 132 is a gap. Such an arrangement simplifies the manufacturing difficulty of the surface acoustic wave resonator 100, and also reduces the quality and manufacturing cost of the surface acoustic wave resonator 100. Of course, the material of the second blocking unit 132 may also include at least one of silicon dioxide (SiO ₂ ) and aluminum (Al). Of course, the material of the second blocking unit 132 may also be other materials with lower acoustic impedance than the first blocking unit 131 , that is, the second blocking unit 132 is solid.

In the above implementation, the material of the third blocking unit 133 can be the same as that of the first blocking unit 131, and the material of the fourth blocking unit 134 can be the same as that of the second blocking unit 132, so as to reduce the material types of the first blocking structure 130 and thereby reduce the difficulty of manufacturing the first blocking structure 130.

10 and 11 , in some embodiments, the width of the first grid bar (first blocking unit 131) parallel to the sound wave transmission direction is d ₁ , the width of the second grid bar (second blocking unit 132) parallel to the sound wave transmission direction is d ₂ , the width of the third grid bar (third blocking unit 133) parallel to the sound wave transmission direction is d ₃ , and the width of the fourth grid bar (fourth blocking unit 134) parallel to the sound wave transmission direction is d ₄ , and d ₁ , d ₂ , d ₃ , and d ₄ satisfy the following relationship:
0.1λ _ss <d ₁ <λ _l
0.1λ _ss <d ₂ <λ _l
0.1λss _{< d3} < _λl
0.1λ _ss <d ₄ <λ _l

Wherein: λ _ss is the wavelength of the slow shear wave of the piezoelectric material layer 110, satisfying λ _ss =v _ss / _fr ; λ _l is the wavelength of the longitudinal compression vibration wave of the piezoelectric material layer 110, satisfying λ _l =v _l / _fr ; v _ss is the wave velocity of the slow shear wave of the piezoelectric material layer 110, v _l is the wave velocity of the longitudinal compression vibration wave, and f _r is the resonant frequency of the surface acoustic wave resonator 100.

Through the above-mentioned arrangement, while ensuring that the first blocking structure 130 has a good energy limiting effect on the target sound wave, the widths of the first grating, the second grating, the third grating and the fourth grating parallel to the sound wave transmission direction are smaller, so as to further reduce the width of the surface acoustic wave resonator 100 along the sound wave transmission direction, thereby further reducing the volume of the surface acoustic wave resonator 100, the filter and the electronic device.

In the above implementation, the width of the first grating parallel to the sound wave transmission direction is d ₁ , the width of the second grating parallel to the sound wave transmission direction is d ₂ , the width of the third grating parallel to the sound wave transmission direction is d ₃ , and the width of the fourth grating parallel to the sound wave transmission direction is d ₄ , which can be equal or unequal as long as the above inequality is satisfied.

Continuing with reference to FIG10 , the thickness of the first bar, the second bar, the third bar and the fourth bar along the direction perpendicular to the preset surface 111 (Z direction) is h1, and the thickness of the transducer 120 electrode along the direction perpendicular to the preset surface 111 (Z direction) is h2, wherein 10h2>h1>0.5h2. This arrangement can ensure that the first blocking structure 130 has a good energy limiting effect on the target sound wave while avoiding the first blocking structure 130 from being too thick along the direction perpendicular to the preset surface 111, thereby reducing the thickness of the surface acoustic wave resonator 100 along the direction perpendicular to the preset surface 111, thereby reducing the volume of the surface acoustic wave resonator 100, the filter and the electronic device.

Continuing to refer to FIG. 10 and FIG. 11, in this embodiment, the surface acoustic wave resonator 100 may also include a second blocking structure 140. The second blocking structure 140 is located on the preset surface 111, and the second blocking structure 140 is arranged on the other side of the transducer 120 along the direction of sound wave transmission. The second blocking structure 140 is used to prevent the sound wave from propagating in a direction away from the transducer 120 (opposite direction of the X direction). The structure and material of the second blocking structure 140 are substantially the same as those of the first blocking structure 130. With reference to the first blocking structure 130, no further description is given here. Taking the orientation shown in FIG. 11 as an example, part of the sound wave is transmitted to the left along the left side of the transducer 120, and the rest of the sound wave is transmitted along the transducer 120. Correspondingly, the first blocking structure 130 is arranged on the right side of the transducer 120, and the second blocking structure 140 is arranged on the left side of the transducer 120, that is, the transducer 120 is located between the first blocking structure 130 and the second blocking structure 140, so as to limit the target sound wave (energy) to the area where the transducer 120 is located through the first blocking structure 130 and the second blocking structure 140, thereby further improving the communication quality.

FIG15 is a graph showing the relationship between the admittance and frequency of the surface acoustic wave resonator provided in the present embodiment. It can be seen from FIG15 that the resonance point of the surface acoustic wave resonator 100 is 682 MHz, and the anti-resonance point of the surface acoustic wave resonator 100 is 721 MHz. The resonance point and anti-resonance point of the surface acoustic wave resonator 100 (as shown in FIG10 and FIG11 ) in the present embodiment are the same as those of the resonator in the related art shown in FIG6 and FIG7 . FIG16 is a graph showing the relationship between the quality factor and frequency of the surface acoustic wave resonator 100 (as shown in FIGS. 10 and 11 ) provided in the embodiment of the present application, wherein curve A (dash-dotted line) is the quality factor curve of the surface acoustic wave resonator 100 in the embodiment of the present application, and curve B (solid line) is the quality factor curve of the resonator in the related art shown in FIGS. 7 and 9 ; as can be seen from FIG16 , before the antiresonance point, the quality factor of the surface acoustic wave resonator 100 in the embodiment of the present application is higher than the quality factor of the resonator in the related art shown in FIGS. 7 and 9 , that is, the energy is limited by the first blocking structure 130 and the second blocking structure 140, thereby improving the quality factor of the surface acoustic wave resonator 100.

Continuing to refer to FIG. 10 , in this embodiment, the surface acoustic wave resonator 100 further includes a functional layer 150 and a substrate layer 160. The functional layer 150 is disposed facing the surface of the piezoelectric material layer 110 opposite to the preset surface 111, and the substrate layer 160 is disposed on the side of the functional layer 150 away from the piezoelectric material layer 110; that is, the functional layer 150 is disposed between the substrate layer 160 and the piezoelectric material layer 110. In this way, the substrate layer 160 can provide support for the functional layer 150 and the piezoelectric material layer 110 to ensure the overall strength of the surface acoustic wave resonator 100.

Exemplarily, the substrate layer 160 may be made of a high acoustic resistance material including silicon (Si), silicon carbide (SiC), sapphire, quartz, etc. This embodiment does not limit the material of the substrate layer 160 as long as it can ensure sufficient support for the functional layer 150 and the piezoelectric material layer 110.

In some implementations, the frequency temperature coefficient of the functional layer 150 is a positive value, that is, when the temperature rises, the resonant frequency of the functional layer 150 shifts toward a high frequency; the frequency temperature coefficient of the piezoelectric material layer 110 is a negative value, that is, when the temperature rises, the resonant frequency of the piezoelectric material layer 110 shifts toward a low frequency; in this way, the piezoelectric material layer 110 and the functional layer 150 compensate each other, which can prevent the resonant frequency of the surface acoustic wave resonator 100 from shifting toward a low frequency or a high frequency, thereby improving the stability of the surface acoustic wave resonator 100.

It is understandable that the material of the functional layer 150 may be various, for example, the material of the functional layer 150 may include silicon dioxide (SiO ₂ ), quartz, etc.

FIG17 is a cross-sectional view 5 of the surface acoustic wave resonator provided by the implementation of the present application. Referring to FIG17 , in other implementations, the piezoelectric material layer 110 in the surface acoustic wave resonator 100 is used to form the acoustic wave and also provides a certain supporting effect. Accordingly, the substrate layer 160 and the functional layer 150 shown in FIG10 may not be provided in the surface acoustic wave resonator 100. In this way, the structure of the surface acoustic wave resonator 100 can be simplified and the manufacturing difficulty of the surface acoustic wave resonator 100 can be reduced. It can be understood that at this time, the piezoelectric material layer 110 needs to have a certain thickness to ensure that the piezoelectric material layer 110 has sufficient supporting force.

FIG18 is a sixth cross-sectional view of a surface acoustic wave resonator provided by the present application. Referring to FIG18 , in the implementation mode in which the surface acoustic wave resonator 100 includes a functional layer 150 and a substrate layer 160, the surface acoustic wave resonator 100 may further include a transition layer 170, and the transition layer 170 may be disposed between the functional layer 150 and the substrate layer 160. The transition layer 170 may be bonded to the surface of the functional layer 150 that is away from the piezoelectric material layer 110, and the transition layer 170 may also be bonded to the surface of the substrate layer 160 that is toward the piezoelectric material layer 110.

Exemplarily, the material of the transition layer 170 may include a dielectric material (such as tantalum oxide (Ta ₂ O ₅ ), sapphire, etc.) or a piezoelectric material (such as aluminum nitride (AlN), zinc oxide (ZnO), etc.).

It is understandable that by properly selecting the material of the transition layer 170 according to the materials of the functional layer 150 and the substrate layer 160, a greater connection force can be achieved between the transition layer 170 and the functional layer 150, and between the transition layer 170 and the substrate layer 160, thereby improving the connection force between the substrate layer 160 and the functional layer 150, that is, improving the process compatibility between different materials. Of course, functional layers 150 of different materials can also be properly selected according to specific functional requirements.

Of course, in some embodiments, the transition layer 170 may also be disposed between the functional layer 150 and the piezoelectric material layer 110, and the transition layer 170 is attached to both the functional layer 150 and the piezoelectric material layer 110. In this case, the connection force between the functional layer 150 and the piezoelectric material layer 110 can be improved.

FIG. 19 is a cross-sectional view of a surface acoustic wave resonator provided by the present application. Referring to FIG. 19 , in this embodiment, the surface acoustic wave resonator 100 may further include a covering layer 180, the covering layer 180 covering the preset surface 111 of the piezoelectric material layer 110, and The cover layer 180 covers the transducer 120 and the first blocking structure 130, that is, the transducer 120 and the first blocking structure 130 are both located in the cover layer 180. In this way, the cover layer 180 can prevent foreign objects from contacting the transducer 120 and the first blocking structure 130, thereby protecting the transducer 120 and the first blocking structure 130, and the cover layer 180 can also seal the transducer 120 and the first blocking structure 130.

In some implementations, the frequency temperature coefficient of the covering layer 180 is positive, that is, the resonant frequency of the covering layer 180 shifts toward high frequency when the temperature rises; the frequency temperature coefficient of the piezoelectric material layer 110 is negative, that is, the resonant frequency of the piezoelectric material layer 110 shifts toward low frequency when the temperature rises; in this way, the piezoelectric material layer 110 and the covering layer 180 compensate each other, which can prevent the resonant frequency of the surface acoustic wave resonator 100 from shifting toward low frequency or high frequency, thereby improving the stability of the surface acoustic wave resonator 100.

For example, the material of the cover layer 180 may include silicon dioxide (SiO ₂ ), quartz, etc.

It can be understood that, in an implementation in which the surface acoustic wave resonator 100 includes the second blocking structure 140 , the cover layer 180 also covers the second blocking structure 140 , that is, the second blocking structure 140 is also located in the cover layer 180 .

It should be noted that in the description of the embodiments of the present application, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or an integral connection; it can also be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims (16)

1. A surface acoustic wave resonator, characterized in that it comprises:

   a piezoelectric material layer;

   A transducer, wherein the transducer is disposed on a predetermined surface of the piezoelectric material layer;

   a first blocking structure, the first blocking structure being located on the preset surface and arranged on one side of the transducer along the sound wave transmission direction, the first blocking structure being used to prevent the target sound wave from propagating in a direction away from the transducer;

   The first blocking structure comprises:

   a first blocking unit;

   The second blocking unit, wherein the first blocking unit is located between the second blocking unit and the transducer; the acoustic impedance of the second blocking unit is different from the acoustic impedance of the first blocking unit.
2. The surface acoustic wave resonator according to claim 1, characterized in that the first blocking structure further comprises:

   a third blocking unit, wherein the acoustic impedance of the third blocking unit is equal to the acoustic impedance of the first blocking unit;

   A fourth blocking unit, wherein the fourth blocking unit is arranged on a side of the second blocking unit away from the transducer, the third blocking unit is located between the fourth blocking unit and the second blocking unit, and the acoustic impedance of the fourth blocking unit is equal to the acoustic impedance of the second blocking unit.
3. The surface acoustic wave resonator according to claim 2 is characterized in that the first blocking unit includes a first grid bar, which extends on the preset surface in a direction perpendicular to the sound wave transmission direction; the second blocking unit includes a second grid bar, which extends on the preset surface in a direction perpendicular to the sound wave transmission direction; the third blocking unit includes a third grid bar, which extends on the preset surface in a direction perpendicular to the sound wave transmission direction; the fourth blocking unit includes a fourth grid bar, which extends on the preset surface in a direction perpendicular to the sound wave transmission direction.
4. The surface acoustic wave resonator according to claim 3 is characterized in that the width of the first grid strip parallel to the acoustic wave transmission direction is d ₁ , the width of the second grid strip parallel to the acoustic wave transmission direction is d ₂ , the width of the third grid strip parallel to the acoustic wave transmission direction is d ₃ , and the width of the fourth grid strip parallel to the acoustic wave transmission direction is d ₄ , and d ₁ , d ₂ , d ₃ , and d ₄ satisfy the following relationship:
   0.1λ _ss <d ₁ <λ _l
   0.1λ _ss <d ₂ <λ _l
   0.1λss _{< d3} < _λl
   0.1λ _ss <d ₄ <λ _l

   Wherein: λ _ss is the wavelength of the slow shear body wave of the piezoelectric material layer, satisfying λ _ss =v _ss / _fr ; λ _l is the wavelength of the longitudinal compression vibration body wave of the piezoelectric material layer, satisfying λ _l =v _l / _fr ; v _ss is the wave velocity of the slow shear body wave of the piezoelectric material layer, v _l is the wave velocity of the longitudinal compression vibration body wave, and f _r is the resonant frequency of the surface acoustic wave resonator.
5. The surface acoustic wave resonator according to any one of claims 1 to 4 is characterized in that the acoustic impedance of the first blocking unit is less than the acoustic impedance of the second blocking unit, and the acoustic impedance of the first blocking unit is less than or equal to the acoustic impedance of the transducer electrode.
6. The surface acoustic wave resonator according to claim 5, characterized in that the first blocking unit is an air wall;

   Alternatively, the material of the first blocking unit includes at least one of silicon dioxide and aluminum.
7. The surface acoustic wave resonator according to claim 5 or 6 is characterized in that the material of the second blocking unit includes at least one of hafnium oxide, hafnium nitride, tungsten nitride, tungsten oxide, tantalum oxide, platinum, tantalum, tungsten, and iridium.
8. The surface acoustic wave resonator according to any one of claims 1 to 4, characterized in that the acoustic impedance of the first blocking unit is greater than the acoustic impedance of the second blocking unit.
9. The surface acoustic wave resonator according to any one of claims 1 to 8, characterized in that the surface acoustic wave resonator further comprises:

   The second blocking structure is located on the preset surface and is arranged on the other side of the transducer along the sound wave transmission direction, and the second blocking structure is used to prevent the sound wave from propagating in a direction away from the transducer.
10. The surface acoustic wave resonator according to any one of claims 1 to 9, characterized in that the surface acoustic wave resonator further comprises include:

    A functional layer, wherein the functional layer is arranged facing a surface of the piezoelectric material layer opposite to the preset surface;

    A substrate layer is disposed on a side of the functional layer facing away from the piezoelectric material layer.
11. The surface acoustic wave resonator according to claim 10 is characterized in that the frequency temperature coefficient of the functional layer is a positive value, and the frequency temperature coefficient of the piezoelectric material layer is a negative value.
12. The surface acoustic wave resonator according to claim 10 or 11 is characterized in that the surface acoustic wave resonator further comprises a transition layer, and the transition layer is arranged between the functional layer and the substrate layer.
13. The surface acoustic wave resonator according to any one of claims 1 to 12, characterized in that the surface acoustic wave resonator further comprises:

    A covering layer is provided, wherein the covering layer covers the preset surface, and the transducer and the first blocking structure are both located in the covering layer.
14. The surface acoustic wave resonator according to claim 13 is characterized in that the frequency temperature coefficient of the covering layer is a positive value, and the frequency temperature coefficient of the piezoelectric material layer is a negative value.
15. A filter, characterized in that it comprises: a housing, and the surface acoustic wave resonator according to any one of claims 1 to 14, wherein the surface acoustic wave resonator is arranged on the housing.
16. An electronic device, comprising: a communication circuit and the filter according to claim 15, wherein the communication circuit is electrically connected to the filter.