Surface acoustic wave device and surface acoustic wave filter

Abstract

The invention provides a surface acoustic wave device and a surface acoustic wave filter, which can be applied to the field of semiconductors and the technical field of communication. The surface acoustic wave device comprises a substrate and a plurality of first resonators arranged on the surface of the substrate, the plurality of first resonators are configured to be connected in series, and the plurality of first resonators are configured to be arranged in a direction orthogonal to a sound wave propagation direction of the surface acoustic wave device; wherein the plurality of first resonators comprise at least one target resonator, the target resonator is configured to be formed by connecting a plurality of sub-resonators in parallel, and the respective sound wave propagation directions of the plurality of sub-resonators and the sound wave propagation directions of the adjacent first resonators are configured to be mutually parallel in a manner that the centers of the sub-resonators are staggered in the sound wave propagation direction, the adjacent first resonators include a first resonator arranged adjacent to the target resonator in the plurality of first resonators.

Description

Technical Field

[0001] The present disclosure relates to the fields of semiconductors and communication technologies, and more particularly, to surface acoustic wave devices and surface acoustic wave filters. Background Art

[0002] In recent years, filters, duplexers, etc. with acoustic wave resonators as basic units have been developing more and more towards miniaturization, high frequency, and broadband, and at the same time, the requirements for the power tolerance of devices in the new generation of communication technologies are also getting higher and higher.

[0003] Considering that the resonator will heat up under power consumption, when the power applied to the resonator is too high, the resonator will fail due to its own excessive temperature. Related technologies improve the heat dissipation of the acoustic wave device by evaporating a transition layer and a combined alloy film electrode layer on the acoustic wave device, and improve the power tolerance of the acoustic wave device by accelerating the heat dissipation speed of the acoustic wave device.

[0004] In the process of implementing the concept of the present disclosure, the inventors found that there are at least the following problems in the related technologies: The degree of improving the power tolerance of the filter by evaporating a material with higher heat dissipation performance on the acoustic wave device is limited. Summary of the Invention

[0005] In view of this, the present disclosure provides a surface acoustic wave device and a surface acoustic wave filter.

[0006] One aspect of the present disclosure provides a surface acoustic wave device, including:

[0007] a substrate, and a plurality of first resonators disposed on the surface of the substrate, wherein the plurality of first resonators are configured to be connected in series, and the plurality of first resonators are configured to be arranged in a direction orthogonal to the acoustic wave propagation direction of the surface acoustic wave device;

[0008] wherein the plurality of first resonators include at least one target resonator, the target resonator is configured to be composed of a plurality of sub-resonators connected in parallel, and the plurality of sub-resonators and adjacent resonators are configured to form a central stagger in the acoustic wave propagation direction, wherein the adjacent resonator is the first resonator adjacent to the target resonator among the plurality of first resonators.

[0009] According to an embodiment of the present disclosure, at least two of the plurality of sub-resonators have different areas from each other.

[0010] According to an embodiment of the present disclosure, the plurality of sub-resonators include a target sub-resonator, and the area of the target sub-resonator is less than or equal to the areas of the other sub-resonators among the plurality of sub-resonators except the at least one target sub-resonator;

[0011] Among them, the resonant frequency of the above-mentioned target sub-resonator is different from the resonant frequencies of the above-mentioned other sub-resonators; and / or

[0012] The anti-resonant frequency of the above-mentioned target sub-resonator is different from the anti-resonant frequencies of the above-mentioned other sub-resonators.

[0013] According to an embodiment of the present disclosure, among the above-mentioned multiple sub-resonators, the acoustic aperture lengths of at least two of the above-mentioned sub-resonators are different; and / or

[0014] The number of finger pairs of at least two of the above-mentioned sub-resonators among the above-mentioned multiple sub-resonators is different.

[0015] According to an embodiment of the present disclosure, the above-mentioned multiple first resonators include multiple target resonators, and the number of sub-resonators included in at least two of the above-mentioned target resonators is different.

[0016] According to an embodiment of the present disclosure, the above-mentioned first resonator or the above-mentioned sub-resonator is composed of an interdigital electrode structure and reflection gratings located on both sides of the interdigital electrode structure;

[0017] Among them, for each of the above-mentioned sub-resonators, the reflection grating included in the sub-resonator is configured to form another sub-resonator adjacent to the sub-resonator together with the interdigital electrode structure adjacent to the reflection grating and another reflection grating.

[0018] According to another aspect of the present disclosure, there is provided a surface acoustic wave filter, including at least one surface acoustic wave device according to any one of the above embodiments, and the at least one surface acoustic wave device is configured to form at least a part of the series arm resonance part of the surface acoustic wave filter.

[0019] According to an embodiment of the present disclosure, the above-mentioned surface acoustic wave filter further includes:

[0020] At least one second resonator;

[0021] Among them, the at least one surface acoustic wave device and the at least one second resonator form the series arm resonance part of the surface acoustic wave filter, and the at least one surface acoustic wave device is configured to be disposed closer to the input terminal of the surface acoustic wave filter than the at least one second resonator.

[0022] According to another aspect of the present disclosure, there is provided a surface acoustic wave filter, including at least one surface acoustic wave device according to any one of the above embodiments, and the at least one surface acoustic wave device is configured to form at least a part of the parallel arm resonance part of the surface acoustic wave filter.

[0023] According to an embodiment of the present disclosure, the above-mentioned surface acoustic wave filter further includes:

[0024] At least one third resonator;

[0025] Wherein, the at least one surface acoustic wave device and the at least one third resonator form a parallel-arm resonance part of the surface acoustic wave filter, and the at least one surface acoustic wave device is configured to be disposed closer to the input terminal of the surface acoustic wave filter than the at least one third resonator.

[0026] According to an embodiment of the present disclosure, a plurality of first resonators are disposed on a substrate surface, and at least one target resonator is disposed among the plurality of resonators. The target resonator is composed of a plurality of parallel sub-resonators, and the sub-resonators and adjacent resonators are configured in a central staggered manner in the acoustic wave propagation direction, thereby weakening the heat transfer effect between adjacent resonators and at least partially solving the problem of low withstand power of the resonator caused by excessive resonator temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above and other objects, features and advantages of the present disclosure will become clearer. In the drawings:

[0028] Figure 1 Schematically shows a schematic diagram of a surface acoustic wave device according to an embodiment of the present disclosure;

[0029] Figure 2 Schematically shows a schematic diagram of a surface acoustic wave device according to another embodiment of the present disclosure;

[0030] Figure 3 Schematically shows a schematic diagram of a surface acoustic wave device according to still another embodiment of the present disclosure;

[0031] Figure 4 Schematically shows a schematic diagram of the interdigital electrodes of the sub-resonator according to an embodiment of the present disclosure;

[0032] Figure 5 Schematically shows a schematic diagram of a surface acoustic wave device according to another embodiment of the present disclosure;

[0033] Figure 6 Schematically shows a schematic diagram of the structural arrangement of the surface acoustic wave device according to an embodiment of the present disclosure; and

[0034] Figure 7 Schematically shows a relationship diagram between the resonance frequency and power consumption of the resonator according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, numerous specific details are set forth in order to provide a comprehensive understanding of the embodiments of the present disclosure. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts of the present disclosure.

[0036] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0037] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0038] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0039] Acoustic wave filters are often used in radio frequency and microwave circuits and are generally used as band-pass filters. A common acoustic wave filter is composed of several acoustic wave resonators combined. Acoustic wave resonators are generally classified into surface acoustic wave (SAW) devices and bulk acoustic wave (BAW) devices according to the vibration mode. SAW devices use inter-digital transducers (IDTs) to convert electrical energy into acoustic energy, or vice versa, to convert acoustic energy into electrical energy. For SAW devices, when the signal power input to the filter device increases, the temperature of the resonator will rise significantly. When the temperature of the resonator exceeds a certain temperature, charge migration will occur in the metal forming the resonator, resulting in a short circuit of the resonator, thereby causing the filter characteristics of the filter device to deteriorate or even fail. Therefore, the power tolerance of the filter device can be improved by reducing the temperature on the resonator.

[0040] In view of this, the present disclosure proposes a surface acoustic wave device and a surface acoustic wave filter.

[0041] Figure 1 Schematically shows a schematic diagram of a surface acoustic wave device according to an embodiment of the present disclosure.

[0042] Embodiments of the present disclosure provide a surface acoustic wave device, including: a substrate, and a plurality of first resonators disposed on the surface of the substrate, wherein the plurality of first resonators are configured to be connected in series, and the plurality of first resonators are configured to be arranged in a direction orthogonal to the acoustic wave propagation direction of the surface acoustic wave device; wherein the plurality of first resonators include at least one target resonator, the target resonator is configured to be composed of a plurality of sub-resonators connected in parallel, and the plurality of sub-resonators and adjacent resonators are configured to form a central stagger in the acoustic wave propagation direction, wherein the adjacent resonator is the first resonator adjacent to the target resonator among the plurality of first resonators.

[0043] As Figure 1 shown, the surface acoustic wave device may include a first resonator 10a and a first resonator 10b. Among them, the first resonator 10a may be the target resonator, that is, the first resonator 10a may include a sub-resonator 101 and a sub-resonator 102. The "+" in each resonator and sub-resonator may represent the central position of the resonator or sub-resonator. The voltage input terminal Vin and the voltage output terminal Vout are respectively applied to both sides of the resonator group formed by the series connection of the first resonator 10a and the first resonator 10b.

[0044] According to an embodiment of the present disclosure, the first resonator 10a and the first resonator 10b are configured to be arranged in a direction orthogonal to the acoustic wave propagation direction, so that the acoustic wave propagation directions of each resonator and sub-resonator present a central stagger effect. As an alternative embodiment, the resonators of the series resonator group do not necessarily need to be set flush at both ends, and the positions at both ends along the acoustic wave propagation direction may be staggered, and finally the acoustic wave propagation directions of each resonator and sub-resonator also present a central stagger effect.

[0045] According to an embodiment of the present disclosure, a plurality of first resonators are connected in series. While ensuring that the total impedance remains unchanged, the power borne by each resonator is reduced. For example, for a resonator with a capacitance of C0, assuming that the total power consumed per unit area is Pdiss, two resonators with a capacitance of 2*C0 are connected in series, the total capacitance is still C0, and the power consumption per unit area becomes Pdiss / 4, thereby improving the overall power tolerance of the resonator.

[0046] According to an embodiment of the present disclosure, a plurality of first resonators are disposed on a substrate surface, and at least one target resonator is disposed among the plurality of resonators. The target resonator is composed of a plurality of parallel sub-resonators, and the sub-resonators and adjacent resonators are arranged in a manner of being centrally staggered in the acoustic wave propagation direction, thereby weakening the heat transfer effect between adjacent resonators and at least partially solving the problem of low tolerable power of the resonator caused by excessive resonator temperature.

[0047] Figure 2 Schematically shows a schematic diagram of a surface acoustic wave device according to another embodiment of the present disclosure.

[0048] As Figure 2 shown, the arrangement of the surface acoustic wave device can also be as shown in the figure, composed of two target resonators, and the sub-resonators in the target resonator and adjacent resonators are arranged in a form of being centrally staggered.

[0049] Figure 3 Schematically shows a schematic diagram of a surface acoustic wave device according to still another embodiment of the present disclosure.

[0050] As Figure 3 shown, the two ends of the two first resonators may not be flush with each other. To ensure that the sub-resonators are arranged in a centrally staggered manner, the two first resonators may be arranged in a staggered manner.

[0051] According to an embodiment of the present disclosure, at least two of the plurality of sub-resonators have different areas respectively. Among the plurality of first resonators disposed on the substrate, a plurality of target resonators may be included. When the number of target resonators is too large, to ensure that the acoustic wave propagation directions of the plurality of sub-resonators are centrally staggered with adjacent resonators, at least two sub-resonators in the surface acoustic wave device are configured as sub-resonators with different areas.

[0052] According to an embodiment of the present disclosure, the plurality of sub-resonators include a target sub-resonator, and the area of the target sub-resonator is less than or equal to the area of other sub-resonators among the plurality of sub-resonators except the target sub-resonator; wherein, the resonance frequency of the target sub-resonator is different from the resonance frequencies of other sub-resonators; and / or the anti-resonance frequency of the target sub-resonator is different from the anti-resonance frequencies of other sub-resonators.

[0053] According to an embodiment of the present disclosure, one or more sub-resonators with the smallest area among multiple sub-resonators are referred to as target sub-resonators. Because the area of the target sub-resonator is small, the power is more concentrated in the target sub-resonator compared with other sub-resonators during use, resulting in the target sub-resonator being more likely to fail than other resonators. There is a correlation between the power tolerance of a resonator and its resonance frequency. The power tolerance of the target sub-resonator can be improved by changing the resonance frequency of the target sub-resonator. Among them, the target sub-resonator can be composed of a substrate, interdigital electrodes, and a reflection grating. Changing the resonance frequency of the target sub-resonator can be achieved by changing the duty cycle of the electrodes or making the interval between electrode fingers narrower.

[0054] According to an embodiment of the present disclosure, at least two of the multiple sub-resonators have different acoustic aperture lengths respectively; and / or at least two of the multiple sub-resonators have different numbers of interdigital pairs respectively. When the resonance frequencies of the target sub-resonator and other sub-resonators are different, at least two of the multiple sub-resonators have different resonance frequencies. To achieve different resonance frequencies of the resonators, based on the principle that the resonance frequency of a resonator is inversely proportional to the capacitance, resonators with different resonance frequencies can be indirectly obtained by changing the capacitance of the resonators. When the resonator is composed of a substrate, interdigital electrodes, and a reflection grating, it can be achieved by changing the acoustic aperture length of the interdigital electrodes or changing the number of interdigital pairs of the interdigital electrodes. It should be clear here that only one of the acoustic aperture length and the number of interdigital pairs of the interdigital electrodes can be changed, or both the acoustic aperture length and the number of interdigital pairs of the interdigital electrodes can be changed simultaneously.

[0055] Figure 4 The structural schematic diagram of the interdigital electrodes of the sub-resonator according to the embodiment of the present disclosure is schematically shown.

[0056] As Figure 4 shown, the interdigital electrodes of the sub-resonator are composed of interleaved metal strips, and these metal strips are called interdigital fingers. The width of the metal strip is called the finger width of the interdigital finger. The width W of the overlapping area of the interdigital fingers in the figure is the finger overlapping length, and the finger overlapping length is also called the acoustic aperture length.

[0057] Among them, both the acoustic aperture length of the interdigital electrodes and the number of interdigital pairs of the sub-resonator are related to the capacitance of the resonator formed by the interdigital electrodes. According to the property that the resonance frequency of a resonator is inversely proportional to its capacitance, the resonance frequency of the resonator can be indirectly changed by changing the capacitance of the interdigital electrodes in the resonator. In addition, when the same resonator is separated, there are strong transverse parasitic modes in the surface acoustic wave device. Therefore, two resonators can be set to different aperture values to weaken the amplitude of the device parasitic modes, thereby improving the smoothness of the filter passband and the group delay performance.

[0058] According to an embodiment of the present disclosure, the plurality of first resonators include a plurality of target resonators, and at least two of the plurality of target resonators each include a different number of sub-resonators.

[0059] Figure 5 The schematic diagram of a surface acoustic wave device according to another embodiment of the present disclosure is schematically shown.

[0060] As Figure 5 shown, all three first resonators are target resonators. The target resonator located in the middle position includes two sub-resonators, and the two first resonators located on both sides include two sub-resonators.

[0061] According to an embodiment of the present disclosure, to ensure that adjacent resonators can be arranged in a central staggered manner even when there are many target resonators, by setting target resonators with at least two different numbers of sub-resonators, the arrangement methods between the plurality of first resonators can be increased as much as possible.

[0062] According to an embodiment of the present disclosure, the first resonator or the sub-resonator is composed of an interdigital electrode structure and reflection gratings located on both sides of the interdigital electrode structure; wherein, for each sub-resonator, the reflection gratings included in the sub-resonator are configured to form another sub-resonator adjacent to the sub-resonator together with the interdigital electrode structure adjacent to the reflection gratings and another reflection grating.

[0063] Figure 6 The schematic diagram of the structural arrangement of a surface acoustic wave device according to an embodiment of the present disclosure is schematically shown.

[0064] As Figure 6 shown, 601 is a reflection grating, and the rest of the structure is an interdigital electrode structure. Reflection gratings are provided on both sides of each interdigital electrode structure, and the interdigital electrode structure and the reflection gratings on both sides together form a sub-resonator. Figure 7 The multiple interdigital electrode structures and reflection gratings in Figure 2 constitute the surface acoustic wave device shown in

[0065] According to an embodiment of the present disclosure, in a plurality of parallel sub-resonators, the interdigital electrode structures constituting the sub-resonators share a reflection grating, which reduces the size of the surface acoustic wave device on the premise of not affecting the performance of the surface acoustic wave device.

[0066] Another aspect of the present disclosure provides a surface acoustic wave filter, including at least one surface acoustic wave device in the above embodiments, and at least one surface acoustic wave device is configured to constitute at least a part of the series arm resonance part of the surface acoustic wave filter.

[0067] According to an embodiment of the present disclosure, the surface acoustic wave filter further includes: at least one second resonator; wherein, at least one surface acoustic wave device and at least one second resonator form a series-arm resonance part of the surface acoustic wave filter, and at least one surface acoustic wave device is configured to be disposed closer to the input terminal of the surface acoustic wave filter than at least one second resonator. Taking the common trapezoidal structure of the surface acoustic wave filter as an example, the trapezoidal surface acoustic wave filter has a series arm and a parallel arm, and the resonance frequencies of the series arm and the parallel arm are different. Under the condition of applying a certain input power, the power consumed by the series arm and the parallel arm at different frequencies is also different.

[0068] Figure 7 Schematically shows a relationship diagram of the resonance frequency and power consumption of the resonator according to an embodiment of the present disclosure.

[0069] As Figure 7 shown, the abscissa represents frequency, and the ordinate represents the power consumed by the resonator. The solid line and the dotted line are the relationships between the power consumption and frequency of two series resonators with different resonance frequencies, and the long dashed line and the short dashed line are the relationships between the power consumption and frequency of two parallel resonators with different resonance frequencies. The passband frequency of this bandpass filter is between the peak of the parallel resonator curve and the peak of the series resonator. Among them, Figure 7 the shown passband frequency is about 2450 - 2580 MHz. From Figure 5 the relationship diagram, it can be seen that the series resonator has a greater power consumption on the right side of the passband, while the parallel resonator has a greater power consumption on the left side of the passband.

[0070] According to an embodiment of the present disclosure, in a surface acoustic wave filter including a parallel arm composed of a surface acoustic wave device and a second resonator according to an embodiment of the present disclosure, the present disclosure considers reducing the number of series resonators in a certain parallel branch and at the same time reducing the resonance frequency of the series resonator to reduce the power consumption of these resonators at a specific frequency. Taking the surface acoustic wave device of the embodiment of the present disclosure as the position close to the input terminal, the surface acoustic wave device can withstand more power than other second resonators, which reduces the power consumed on the second resonator to a certain extent. Assuming that the power tolerance of the second resonator is lower than that of the surface acoustic wave device, configuring the surface acoustic wave device at the position close to the input terminal improves the maximum power that the surface acoustic wave filter can withstand to a certain extent.

[0071] Another aspect of the present disclosure provides a surface acoustic wave filter, including a surface acoustic wave device of any embodiment, and at least one surface acoustic wave device is configured to form at least a part of a parallel-arm resonance part of the surface acoustic wave filter.

[0072] According to an embodiment of the present disclosure, the surface acoustic wave filter further includes: at least one third resonator; wherein, at least one surface acoustic wave device and at least one third resonator form a parallel-arm resonance section of the surface acoustic wave filter, and at least one surface acoustic wave device is configured to be disposed closer to the input terminal of the surface acoustic wave filter than at least one third resonator.

[0073] According to an embodiment of the present disclosure, the surface acoustic wave device of the present disclosure can also be used in the parallel-arm resonance section of the surface acoustic wave filter. As the number of series-connected resonators increases, the area of the surface acoustic wave filter further increases. The present disclosure considers reducing the number of series-connected resonators in a certain parallel branch while increasing the resonance frequency of the corresponding resonator to reduce the power consumption of these resonators at a specific frequency.

[0074] According to an embodiment of the present disclosure, taking a conventional surface acoustic wave device as an example, the middle region of the device is the hottest region. In contrast, in a piezoelectric material surface acoustic wave device, a piezoelectric layer with a poor thermal conductivity forms a thin film, while silicon, Al 2 O 3 etc. constitute the main part of the substrate, improving the heat dissipation characteristics of the device, resulting in a relatively uniform temperature distribution in the plane of the piezoelectric material surface acoustic wave device. Therefore, considering the mutual heat transfer between resonators, the method of staggering the centers of adjacent resonators in the surface acoustic wave device mentioned in the present disclosure to improve power tolerance has a more significant effect on the piezoelectric material surface acoustic wave device.

[0075] Those skilled in the art can understand that the features recited in the various embodiments and / or claims of the present disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly recited in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features recited in the various embodiments and / or claims of the present disclosure can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0076] The above describes the embodiments of the present disclosure. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present disclosure. Although the embodiments are described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A surface acoustic wave device, comprising: a substrate, and a plurality of first resonators disposed on the surface of the substrate, wherein the plurality of first resonators are configured to be connected in series, and the plurality of first resonators are arranged in a direction orthogonal to the acoustic wave propagation direction of the surface acoustic wave device; wherein the plurality of first resonators include at least one target resonator, the target resonator is configured to be composed of a plurality of sub-resonators connected in parallel, and the plurality of sub-resonators and adjacent resonators are configured to form a central stagger in the acoustic wave propagation direction, wherein the adjacent resonator is the first resonator adjacent to the target resonator among the plurality of first resonators.

2. The surface acoustic wave device according to claim 1, wherein, at least two of the plurality of sub-resonators have different areas respectively.

3. The surface acoustic wave device according to claim 2, wherein, the plurality of sub-resonators include a target sub-resonator, and the area of the target sub-resonator is less than or equal to the areas of the other sub-resonators among the plurality of sub-resonators except the target sub-resonator; wherein the resonance frequency of the target sub-resonator is different from the resonance frequencies of the other sub-resonators; and / or the anti-resonance frequency of the target sub-resonator is different from the anti-resonance frequencies of the other sub-resonators.

4. The surface acoustic wave device according to claim 2, wherein, at least two of the plurality of sub-resonators have different acoustic aperture lengths respectively; and / or at least two of the plurality of sub-resonators have different numbers of finger pairs respectively.

5. The surface acoustic wave device according to claim 1, wherein, the plurality of first resonators include a plurality of target resonators, and at least two of the plurality of target resonators include different numbers of sub-resonators respectively.

6. The surface acoustic wave device according to claim 1, wherein, the first resonator or the sub-resonator is composed of an interdigital electrode structure and reflection gratings located on both sides of the interdigital electrode structure; wherein for each of the sub-resonators, the reflection gratings included in the sub-resonator are configured to form another sub-resonator adjacent to the sub-resonator together with the interdigital electrode structure adjacent to the reflection gratings and another reflection grating.

7. A surface acoustic wave filter comprising at least one surface acoustic wave device according to any one of claims 1 to 6, and the at least one surface acoustic wave device is configured to form at least a part of the series arm resonance section of the surface acoustic wave filter.

8. The surface acoustic wave filter according to claim 7, further comprising: at least one second resonator; wherein the at least one surface acoustic wave device and the at least one second resonator form the series arm resonance section of the surface acoustic wave filter, and the at least one surface acoustic wave device is configured to be disposed closer to the input terminal of the surface acoustic wave filter than the at least one second resonator.

9. A surface acoustic wave filter includes at least one surface acoustic wave device as described in any one of claims 1 to 6, and the at least one surface acoustic wave device is configured to form at least a part of a shunt-arm resonance section of the surface acoustic wave filter.

10. The surface acoustic wave filter according to claim 9, further comprising: at least one third resonator; wherein, the at least one surface acoustic wave device and the at least one third resonator form the shunt-arm resonance section of the surface acoustic wave filter, and the at least one surface acoustic wave device is configured to be disposed closer to an input terminal of the surface acoustic wave filter than the at least one third resonator.

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