A surface acoustic wave resonator and a radio frequency filter

Abstract

Embodiments of the present invention provide a surface acoustic wave resonator and a radio frequency filter. The surface acoustic wave resonator includes: a substrate; a piezoelectric layer located on the substrate; an electrode layer located on the side of the piezoelectric layer away from the substrate; the electrode layer includes a plurality of interdigital transducers, and the interdigital transducer includes: a first bus bar and first electrode fingers and first dummy electrode fingers alternately arranged and connected to the first bus bar; a second bus bar and second electrode fingers and second dummy electrode fingers alternately arranged and connected to the second bus bar; the first electrode fingers and the second dummy electrode fingers are arranged opposite to each other, and the second electrode fingers and the first dummy electrode fingers are arranged opposite to each other. The surface acoustic wave resonator and the radio frequency filter provided by the embodiments of the present invention can achieve the flexibility of bandwidth selection without replacing the substrate and the piezoelectric layer, nor adding additional structural units, further improving the design freedom of the product.

Description

Technical Field

[0001] The present invention relates to the field of communications, and particularly to a surface acoustic wave resonator and a radio frequency filter. Background Art

[0002] With the development of communication technology from 2G to 5G, the number of communication frequency bands has gradually increased (from 4 frequency bands in 2G to more than 50 frequency bands in 5G). In order to improve the compatibility of smart phones with different communication systems, the demand for filters in 5G smart phones will increase significantly, driving the large-scale growth of the filter market. Currently, the radio frequency filters widely used in wireless communication terminals are surface acoustic wave filters, which are responsible for receiving and transmitting radio frequency signals in the channels and outputting signals with specific frequencies from the input multiple radio frequency signals. At the same time, with the continuous development of mobile communication technology and the modular development of the radio frequency front end, the market demand for filters tends to be more complex, high-end, and miniaturized.

[0003] Surface acoustic wave devices based on single-crystal piezoelectric lithium tantalate substrates have been widely used in radio frequency filters. Limited by the Q value and high frequency temperature coefficient of single-crystal piezoelectric materials, it is difficult to meet the requirements of radio frequency front-end chips. The traditional method of adjusting the bandwidth generally selects piezoelectric materials with different tangents or uses the method of shunting capacitors in the design of radio frequency filters to reduce the electromechanical coupling coefficient of specific resonators and achieve the purpose of improving the rectangularity. Summary of the Invention

[0004] The surface acoustic wave resonator provided by the embodiment of the present invention can achieve the flexibility of bandwidth selection without replacing the substrate and the piezoelectric layer, nor adding additional structural units, further improving the design freedom of the product.

[0005] In a first aspect, the embodiment of the present invention provides a surface acoustic wave resonator, which includes:

[0006] A substrate;

[0007] A piezoelectric layer located on the substrate;

[0008] An electrode layer, which is located on the side of the piezoelectric layer away from the substrate;

[0009] The electrode layer includes a plurality of interdigital transducers, and each interdigital transducer includes: a first bus bar and first electrode fingers and first dummy electrode fingers alternately arranged and connected to the first bus bar; a second bus bar and second electrode fingers and second dummy electrode fingers alternately arranged and connected to the second bus bar; the first electrode fingers and the second dummy electrode fingers are arranged opposite to each other, and the second electrode fingers and the first dummy electrode fingers are arranged opposite to each other;

[0010] Among them, the included angle between the first electrode finger and the first bus bar, the included angle between the second electrode finger and the second bus bar, the included angle between the first dummy electrode finger and the first bus bar, and the included angle between the second dummy electrode finger and the second bus bar are equal; the value range of the included angle is 75° to 90° and -75° to -90°.

[0011] Optionally, both the first electrode finger and the second electrode finger include a main body and two end heads;

[0012] The end head is connected to the main body, and the end head and the main body share at least part of each other;

[0013] Along the length direction of the first bus bar, the width of the end head is greater than the width of the main body.

[0014] Optionally, along the length direction of the first bus bar, the width of the end head is 1.2 to 1.8 times the width of the main body.

[0015] Optionally, the length of the end head in the direction perpendicular to the length direction of the first bus bar is 0.3 to 0.7 times the wavelength of the interdigital transducer.

[0016] Optionally, the distance between the two end heads on the first electrode finger and the distance between the two end heads on the second electrode finger are both equal to the aperture of the interdigital transducer;

[0017] Among them, the end head of the first electrode finger far from the first bus bar is arranged opposite to the second dummy electrode finger, and the end head of the second electrode finger far from the second bus bar is arranged opposite to the first dummy electrode finger.

[0018] Optionally, the electrode layer further includes a plurality of reflection grating structures;

[0019] The reflection grating structure includes a third bus bar, a fourth bus bar, and a plurality of reflection gratings;

[0020] The third bus bar and the fourth bus bar are arranged in parallel;

[0021] The first end of the reflection grating is connected to the third bus bar, and the second end of the reflection grating is connected to the fourth bus bar;

[0022] Along the length direction of the first bus bar, the reflection grating structure is located on both sides of the interdigital transducer;

[0023] The value range of the included angle between the reflection grating and the third bus bar is 75° to 90° and -75° to -90°.

[0024] Optionally, along the length direction of the first bus bar, the ratio of the width of the main body to the wavelength of the interdigital transducer is less than 0.5.

[0025] Optionally, the piezoelectric material of the piezoelectric layer includes a positioning edge, the positioning edge of the piezoelectric material is perpendicular to the length directions of the first bus bar and the second bus bar, and the propagation direction of the surface acoustic wave is perpendicular to the positioning edge of the piezoelectric material.

[0026] Optionally, the surface acoustic wave resonator provided by the embodiment of the present invention further includes an energy trap layer, and the energy trap layer is located between the substrate and the piezoelectric layer;

[0027] A first dielectric layer, the first dielectric layer is located between the energy trap layer and the piezoelectric layer;

[0028] A second dielectric layer, the second dielectric layer is located on the side of the electrode layer away from the piezoelectric layer and covers the electrode layer.

[0029] In a second aspect, the embodiment of the present invention further provides a radio frequency filter, and the radio frequency filter includes the surface acoustic wave resonator provided by any embodiment of the present invention.

[0030] For the surface acoustic wave resonator provided by the embodiment of the present invention, the bandwidth can be freely adjusted by rotating the first electrode finger, the first dummy electrode finger, the second electrode finger and the second dummy electrode finger in the electrode layer. When the user needs different bandwidths, only need to rotate the first electrode finger, the first dummy electrode finger, the second electrode finger and the second dummy electrode finger in the interdigital transducer by a certain angle to achieve bandwidth selectivity. For the surface acoustic wave resonator provided by the embodiment of the present invention, without replacing the substrate and the piezoelectric layer, and without adding additional structural units, the flexibility of bandwidth selection can be achieved, and the design freedom of the product is further improved. Description of the Drawings

[0031] Figure 1 It is a schematic structural diagram of a surface acoustic wave resonator provided by an embodiment of the present invention;

[0032] Figure 2 It is a schematic structural diagram of an interdigital transducer provided by an embodiment of the present invention;

[0033] Figure 3 It is a schematic structural diagram of the first electrode finger during rotation provided by an embodiment of the present invention;

[0034] Figure 4 It is a schematic diagram of the measured results of the surface acoustic wave resonator provided by an embodiment of the present invention;

[0035] Figure 5Schematic diagram of the relationship between the relative bandwidth and the included angle of the surface acoustic wave resonator provided by the embodiment of the present invention;

[0036] Figure 6 Schematic diagram of the relationship between the relative bandwidth of different surface acoustic wave resonators and the half-wavelength of different interdigital transducers;

[0037] Figure 7 Schematic diagram of the structure of another interdigital transducer provided by the embodiment of the present invention;

[0038] Figure 8 Top view structure schematic diagram of an electrode layer provided by the embodiment of the present invention;

[0039] Figure 9 Top view structure schematic diagram of a surface acoustic wave resonator provided by the embodiment of the present invention;

[0040] Figure 10 Schematic diagram of the relationship between the insertion loss and the frequency of the RF filter. Detailed implementation manners

[0041] The following further describes the embodiments of the present invention in detail with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention, rather than limiting the embodiments of the present invention. In addition, it should be noted that for the convenience of description, only parts related to the embodiments of the present invention are shown in the drawings, rather than all structures.

[0042] Figure 1 Schematic diagram of the structure of a surface acoustic wave resonator provided by the embodiment of the present invention, Figure 2 Schematic diagram of the structure of an interdigital transducer provided by the embodiment of the present invention, refer to Figure 1 and Figure 2, the surface acoustic wave resonator provided by the embodiment of the present invention includes: a substrate 110; a piezoelectric layer 120 located on the substrate 110; an electrode layer 130, the electrode layer 130 is located on the side of the piezoelectric layer 120 away from the substrate 110; the electrode layer 130 includes a plurality of interdigital transducers 131, and the interdigital transducer 131 includes: a first bus bar 10 and first electrode fingers 20 and first dummy electrode fingers 30 alternately arranged and connected to the first bus bar 10; a second bus bar 40 and second electrode fingers 50 and second dummy electrode fingers 60 alternately arranged and connected to the second bus bar 40; the first electrode fingers 20 and the second dummy electrode fingers 60 are arranged opposite to each other, and the second electrode fingers 50 and the first dummy electrode fingers 30 are arranged opposite to each other; wherein, the angle θ between the first electrode fingers 20 and the first bus bar 10, the angle θ between the second electrode fingers 50 and the second bus bar 40, the angle θ between the first dummy electrode fingers 30 and the first bus bar 10, and the angle θ between the second dummy electrode fingers 60 and the second bus bar 40 are equal; the value range of the angle θ is 75° to 90° and -75° to -90°.

[0043] Specifically, the material of the substrate 110 can be high-resistance silicon, and the high-resistance silicon can be P-type high-resistance silicon or N-type high-resistance silicon. The resistivity of the high-resistance silicon is greater than 2000 Ω·cm. Preferably, the resistivity of the high-resistance silicon is greater than 10000 Ω·cm. The material of the piezoelectric layer 120 can be lithium tantalate and lithium niobate, and the cut angle of the lithium tantalate can be 30° to 50°. The thickness of the piezoelectric layer 120 can be in the range of 300 to 1000 nm. The electrode layer 130 is formed by depositing a metal film on the surface of the piezoelectric layer 120 by means of electron beam evaporation, plasma, magnetron sputtering, etc. Among them, the material of the deposited metal film can be titanium, chromium, copper, silver, aluminum, etc. or a combination thereof. In an embodiment of the present invention, the number of the first electrode fingers 20, the first dummy electrode fingers 30, the second electrode fingers 50, and the second dummy electrode fingers 60 are equal. In the embodiment of the present invention, the magnitudes of the angles between the first electrode fingers 20 and the first bus bar 10, the angles between the second electrode fingers 50 and the second bus bar 40, the angles between the first dummy electrode fingers 30 and the first bus bar 10, and the angles between the second dummy electrode fingers 60 and the second bus bar 40 can be adjusted. By simultaneously rotating the first electrode fingers 20, the second electrode fingers 50, the first dummy electrode fingers 30, and the second dummy electrode fingers 60, the magnitudes of the angles can be adjusted. Figure 3 It is a schematic structural diagram of the first electrode finger in the rotation process provided by the embodiment of the present invention. Refer to Figure 3 , the range of the angle β that the first electrode finger 20 can rotate is -15° to 15°. When the first electrode finger 20 is rotated clockwise by 0 to 15°, the angle θ between the first electrode finger 20 and the first bus bar 10 ranges from 75° to 90°. When the first electrode finger 20 is rotated counterclockwise by 0 to 15°, the angle θ between the first electrode finger 20 and the first bus bar 10 ranges from -75° to -90°.

[0044] Figure 4 Schematic diagram of the measured results of the surface acoustic wave resonator provided by the embodiment of the present invention. Refer to Figure 4 , after normalizing the resonance frequency, it can be seen that the relative bandwidth of the surface acoustic wave resonator gradually decreases when the rotation angle β of the first electrode finger increases from 0° to 5°, then to 7°, and then to 9°. Figure 5 Schematic diagram of the relationship between the relative bandwidth and the included angle of the surface acoustic wave resonator provided by the embodiment of the present invention. Refer to Figure 5 , when the first electrode finger is not rotated, that is, when β = 0°, the relative bandwidth of the surface acoustic wave resonator is 4.37%. When the first electrode finger is rotated clockwise by 9°, that is, when β = 9°, the relative bandwidth of the surface acoustic wave resonator is 3.57%. And during the process of the rotation angle of the first electrode finger increasing from 0°, 5°, 7° to 9° clockwise, the relative bandwidth of the surface acoustic wave resonator gradually decreases. Therefore, the relative bandwidth can be freely adjusted by rotating the first electrode finger. Figure 6 Schematic diagram of the relationship between the relative bandwidth of different surface acoustic wave resonators and the half-wavelength of different interdigital transducers. Refer to Figure 6 , Figure 6 The solid line in Figure 6 represents the schematic diagram of the relationship between the relative bandwidth of the surface acoustic wave resonator when the first electrode finger is not rotated and the half-wavelength of the interdigital transducer. Figure 6 The dotted line in Figure 6The ordinate in [figure] represents the magnitude of the relative bandwidth. When the half-wavelength of the interdigital transducer is 0.75 μm, the relative bandwidth of the surface acoustic wave resonator with the first electrode fingers not rotated is 3.6%, and the relative bandwidth of the surface acoustic wave resonator with the first electrode fingers rotated clockwise by 7° is less than 3.2%. When the half-wavelength of the interdigital transducer is 1 μm, the relative bandwidth of the surface acoustic wave resonator with the first electrode fingers not rotated is 4.2%, and the relative bandwidth of the surface acoustic wave resonator with the first electrode fingers rotated clockwise by 7° is less than 3.8%. During the process of gradually increasing the half-wavelength of the interdigital transducer from 0.75 μm to 1.2 μm with a step size of 0.05 μm, the relative bandwidth of the surface acoustic wave resonator with the first electrode fingers rotated by 7° is always less than that of the surface acoustic wave resonator with the first electrode fingers not rotated. And at different half-wavelengths of the interdigital transducer, rotating the first electrode fingers by 7° can reduce the relative bandwidth of the surface acoustic wave resonator. It can be seen that by rotating the first electrode fingers in the surface acoustic wave resonator provided in the embodiment of the present invention, the relative bandwidth of the surface acoustic wave resonator can be freely adjusted, greatly improving the design freedom of the product. It should be noted that in the embodiment of the present invention, only the rotation of the first electrode fingers is described, but actually when the first electrode fingers are rotated, the first dummy electrode fingers, the second electrode fingers, and the second dummy electrode fingers are also rotated, and the rotation angles are the same.

[0045] For the surface acoustic wave resonator provided in the embodiment of the present invention, the free adjustment of the bandwidth can be achieved by rotating the first electrode fingers, the first dummy electrode fingers, the second electrode fingers, and the second dummy electrode fingers in the electrode layer. When different bandwidths are required, only by rotating the first electrode fingers, the second electrode fingers, the first dummy electrode fingers, and the second dummy electrode fingers in the interdigital transducer in the electrode layer can the free adjustment of the relative bandwidth be achieved. For the surface acoustic wave resonator provided in the embodiment of the present invention, without replacing the substrate and the piezoelectric layer, and without adding additional structural units, the flexibility of bandwidth selection can be achieved, further improving the design freedom of the product.

[0046] Optionally, Figure 7 is a schematic structural diagram of another interdigital transducer provided in the embodiment of the present invention. Refer to Figure 7 , both the first electrode fingers 20 and the second electrode fingers 50 include a main body 11 and two end heads 12; the end heads 12 are connected to the main body 11, and the end heads 12 and the main body 11 share at least a part; along the length direction of the first bus bar 10, the width a of the end heads 12 is greater than the width b of the main body 11.

[0047] Specifically, the propagation direction of the surface acoustic wave is parallel to the length direction of the first bus bar 10, Figure 7The arrow in it indicates the propagation direction of the surface acoustic wave. Setting the width a of the end 12 to be greater than the width b of the main body 11 can enable the end 12 to block the leakage of the transverse energy in the surface acoustic wave, suppress the clutter in the surface acoustic wave, and improve the Q value of the surface acoustic wave resonator. It should be noted that Figure 7 only the shape of the end is exemplarily drawn as a rectangle, and the shape of the end can also be a triangle or a polygon.

[0048] Optionally, continue to refer to Figure 7 , along the length direction of the first bus bar 10, the width a of the end 10 is 1.2 to 1.8 times the width b of the main body 11.

[0049] Specifically, setting the width a of the end to be 1.2 to 1.8 times the width b of the main body can further enable the end to block the leakage of the transverse energy in the surface acoustic wave, better suppress the clutter in the surface acoustic wave, and further improve the Q value of the surface acoustic wave resonator.

[0050] Optionally, continue to refer to Figure 7 , the length c of the end 12 in the direction perpendicular to the length direction of the first bus bar 10 is 0.3 to 0.7 times the wavelength of the interdigital transducer.

[0051] Specifically, setting the length c of the end 12 in the direction perpendicular to the length direction of the first bus bar 10 to be 0.3 to 0.7 times the wavelength of the interdigital transducer can further enable the end 12 to block the leakage of the transverse energy in the surface acoustic wave, better suppress the clutter in the surface acoustic wave, and further improve the Q value of the surface acoustic wave resonator.

[0052] Optionally, continue to refer to Figure 7 , the distance between the two ends 12 on the first electrode finger 20 and the distance between the two ends 12 on the second electrode finger 50 are both equal to the aperture of the interdigital transducer 131; wherein, the end 12 on the first electrode finger 20 far from the first bus bar 10 is disposed opposite to the second dummy electrode finger 60, and the end 12 on the second electrode finger 50 far from the second bus bar 40 is disposed opposite to the first dummy electrode finger 30.

[0053] Specifically, the distance between the two ends 12 on the first electrode finger 20 and the distance between the two ends 12 on the second electrode finger 50 are both represented by Figure 7The h in it indicates that the size of h is equal to the aperture of the interdigital transducer 131. Two end heads 12 are provided on the main body 11, and one of the end heads 12 is disposed opposite to the first dummy electrode finger 30 or the second dummy electrode finger 60. One of the end heads 12 on the first electrode finger 20 is disposed opposite to the second dummy electrode finger 60, and one of the end heads 12 on the second electrode finger 50 is disposed opposite to the first dummy electrode finger 30. Such a design can further prevent the lateral energy leakage in the surface acoustic wave by the end head 12, better suppress the clutter in the surface acoustic wave, and further improve the Q value of the surface acoustic wave resonator.

[0054] Optionally, Figure 8 is a top view structural schematic diagram of an electrode layer provided by an embodiment of the present invention. Refer to Figure 8 , the electrode layer further includes a plurality of reflection grating structures 132; the reflection grating structure 132 includes a third bus bar 70, a fourth bus bar 80, and a plurality of reflection gratings 90; the third bus bar 70 and the fourth bus bar 80 are arranged in parallel; the first end of the reflection grating 90 is connected to the third bus bar 70, and the second end of the reflection grating 90 is connected to the fourth bus bar 80; along the length direction of the first bus bar 10, the reflection grating structures 132 are located on both sides of the interdigital transducer; the included angle between the reflection grating 90 and the third bus bar 70 ranges from 75° to 90° and -75° to -90°.

[0055] Specifically, the reflection grating structure 132 can reflect the energy of the surface acoustic wave, concentrate the energy in the interdigital transducer. When rotating the first electrode finger, the reflection grating 90 is rotated simultaneously, and the rotation angle of the reflection grating 90 is the same as the rotation angle of the first electrode finger. By changing the size of the included angle between the reflection grating 90 and the third bus bar 70, the Q value of the surface acoustic wave resonator is further improved. Among them, the number of reflection grating bars in each reflection grating structure 132 is 15 - 30.

[0056] Optionally, along the length direction of the first bus bar, the ratio of the width of the main body to the wavelength of the interdigital transducer is less than 0.5.

[0057] Specifically, the duty cycle of the surface acoustic wave resonator is equal to the ratio of the width of the main body to the wavelength of the interdigital transducer. When the ratio of the width of the main body to the wavelength of the interdigital transducer is less than 0.5, the improvement of the Q value of the surface acoustic wave resonator is more obvious.

[0058] Optionally, Figure 9 is a top view structural schematic diagram of a surface acoustic wave resonator provided by an embodiment of the present invention. Refer to Figure 9 , the piezoelectric material of the piezoelectric layer 120 includes a positioning edge 121. The positioning edge 121 of the piezoelectric material is perpendicular to the length direction of the first bus bar and the length direction of the second bus bar, and the propagation direction of the surface acoustic wave is perpendicular to the positioning edge 121 of the piezoelectric material.

[0059] Specifically, a positioning edge 121 is provided in the piezoelectric material. Both the first bus bar and the second bus bar are perpendicular to the positioning edge 121, which can make each interdigital transducer in the electrode layer arranged parallel to each other. Since the propagation direction of the surface acoustic wave is perpendicular to the positioning edge 121, each first electrode finger and the second electrode finger in the interdigital transducer can block the leakage of the transverse energy in the surface acoustic wave, better suppress the clutter in the surface acoustic wave, and further improve the Q value of the surface acoustic wave resonator.

[0060] Optionally, continue to refer to Figure 1 The surface acoustic wave resonator provided by the embodiment of the present invention further includes an energy trap layer 140 located between the substrate 110 and the piezoelectric layer 120; a first dielectric layer 150 located between the energy trap layer 140 and the piezoelectric layer 120; and a second dielectric layer 160 located on the side of the electrode layer 130 away from the piezoelectric layer 120 and covering the electrode layer 130.

[0061] Specifically, an energy trap layer 140 is prepared on the substrate 110. The material of the energy trap layer 140 can be polysilicon. The setting of the energy trap layer 140 can reduce the accumulation of charges, achieving the purpose of improving the Q value of the surface acoustic wave resonator. A low sound velocity silicon dioxide is grown on the side of the energy trap layer 140 away from the substrate 110 by plasma enhanced chemical vapor deposition or thermal oxidation of silicon, thereby forming the first dielectric layer 150. Chemical mechanical planarization treatment is adopted to finally control the thickness value of the first dielectric layer 150 within the range of 300-800 nm. The setting of the first dielectric layer 150 can further improve the temperature drift coefficient. The second dielectric layer 160 serves as a passivation layer and a frequency modulation layer of the surface acoustic wave resonator. The material of the second dielectric layer 160 can be silicon dioxide or silicon nitride, and the second dielectric layer 160 covers the electrode layer 130. The substrate 110, the energy trap layer 140, and the first dielectric layer 150 provided by the embodiment of the present invention form a composite multi-layer substrate, and the composite multi-layer substrate can endow the surface acoustic wave resonator and the radio frequency filter with characteristics such as low insertion loss, smooth passband, high Q value, and excellent low-frequency temperature.

[0062] The embodiment of the present invention also provides a radio frequency filter, which includes the surface acoustic wave resonator provided by any embodiment of the present invention.

[0063] Specifically, Figure 10 is a schematic diagram of the relationship between the insertion loss and the frequency of the radio frequency filter. Refer to Figure 10 Figure 10 The dotted line in shows the relationship between the insertion loss and the frequency of the radio frequency filter provided by the embodiment of the present invention. The rotation angle of the first electrode finger in the surface acoustic wave resonator in the radio frequency filter is 7°. Figure 10 ​The solid line in [description] represents the relationship between the insertion loss and frequency of a radio frequency filter in the prior art. The radio frequency filter in the prior art and the radio frequency filter provided in the embodiments of the present invention adopt the same topology and surface acoustic wave resonator structure parameters. From Figure 10 it can be seen that, compared with the radio frequency filter in the prior art, the radio frequency filter provided in the embodiments of the present invention has consistent indicators such as insertion loss and bandwidth, but the right-end rectangularity of the radio frequency filter provided in the embodiments of the present invention is improved, greatly improving the design freedom of the product.

[0064] Note that the above is only the preferred embodiment of the embodiments of the present invention and the applied technical principles. Those skilled in the art will understand that the embodiments of the present invention are not limited to the specific embodiments described herein. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the embodiments of the present invention. Therefore, although the embodiments of the present invention have been described in more detail through the above embodiments, the embodiments of the present invention are not limited to the above embodiments. Without departing from the concept of the embodiments of the present invention, more other equivalent embodiments can be included, and the scope of the embodiments of the present invention is determined by the scope of the appended claims.

Claims

1. A surface acoustic wave resonator, characterized in that, Comprising: A substrate; A piezoelectric layer located on the substrate; An electrode layer, the electrode layer being located on a side of the piezoelectric layer away from the substrate; The electrode layer includes a plurality of interdigital transducers, and the interdigital transducer includes: a first bus bar and first electrode fingers and first dummy electrode fingers alternately arranged and connected to the first bus bar; a second bus bar and second electrode fingers and second dummy electrode fingers alternately arranged and connected to the second bus bar; the first electrode fingers and the second dummy electrode fingers are arranged opposite to each other, and the second electrode fingers and the first dummy electrode fingers are arranged opposite to each other; Wherein, an included angle between the first electrode finger and the first bus bar, an included angle between the second electrode finger and the second bus bar, an included angle between the first dummy electrode finger and the first bus bar, and an included angle between the second dummy electrode finger and the second bus bar are equal; the value range of the included angle is 75° to 90° and -75° to -90°; both the first electrode finger and the second electrode finger include a main body and two end heads; the end heads are connected to the main body, and the end heads and the main body share at least part; along the length direction of the first bus bar, the width of the end head is greater than the width of the main body; along the length direction of the first bus bar, the width of the end head is 1.2 to 1.8 times the width of the main body; the electrode layer has a plurality of reflection grating structures.

2. The resonator according to claim 1, characterized in that, The length of the end head in a direction perpendicular to the length direction of the first bus bar is 0.3 to 0.7 times the wavelength of the interdigital transducer.

3. The resonator according to claim 1, characterized in that, The distance between the two end heads on the first electrode finger and the distance between the two end heads on the second electrode finger are both equal to the aperture of the interdigital transducer; Wherein, the end head of the first electrode finger away from the first bus bar is arranged opposite to the second dummy electrode finger, and the end head of the second electrode finger away from the second bus bar is arranged opposite to the first dummy electrode finger.

4. The surface acoustic wave resonator according to claim 1, characterized in that, The reflection grating structure includes a third bus bar, a fourth bus bar, and a plurality of reflection gratings; The third bus bar and the fourth bus bar are arranged in parallel; A first end of the reflection grating is connected to the third bus bar, and a second end of the reflection grating is connected to the fourth bus bar; Along the length direction of the first bus bar, the reflection grating structure is located on both sides of the interdigital transducer; The value range of the included angle between the reflection grating and the third bus bar is 75° to 90° and -75° to -90°.

5. The surface acoustic wave resonator according to claim 1, characterized in that, Along the length direction of the first bus bar, the ratio of the width of the main body to the wavelength of the interdigital transducer is less than 0.

5.

6. The surface acoustic wave resonator according to claim 1, characterized in that, The piezoelectric material of the piezoelectric layer includes a positioning edge, the positioning edge of the piezoelectric material is perpendicular to the length direction of the first bus bar and the length direction of the second bus bar, and the propagation direction of the surface acoustic wave is perpendicular to the positioning edge of the piezoelectric material.

7. The surface acoustic wave resonator according to claim 1, characterized in that, It further includes an energy trap layer, and the energy trap layer is located between the substrate and the piezoelectric layer; A first dielectric layer, the first dielectric layer is located between the energy trap layer and the piezoelectric layer; A second dielectric layer, the second dielectric layer is located on a side of the electrode layer away from the piezoelectric layer and covers the electrode layer.

8. A radio frequency filter, characterized in that, Including the surface acoustic wave resonator according to any one of claims 1-7.

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