A surface acoustic wave resonator and a radio frequency filter

Abstract

An embodiment of the present invention provides 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 a side of the piezoelectric layer away from the substrate; the electrode layer includes interdigital transducers, and the interdigital transducers include: 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, a first gap is provided between the first electrode fingers and the second dummy electrode, the second electrode fingers and the first dummy electrode fingers are arranged opposite to each other, and a second gap is provided between the second electrode fingers and the first dummy electrode; wherein, each of the first gaps is arranged along a first direction, and each of the second gaps is arranged along the first direction. The surface acoustic wave resonator and the radio frequency filter provided by the embodiment of the present invention can effectively suppress the lateral mode ripples.

Description

Technical Field

[0001] The present invention relates to the field of communications, and in particular, 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 (rising 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 amount of filters required for 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 among the input multiple radio frequency signals. At the same time, with the continuous development of mobile communication technology and the development of radio frequency front-end modularization, 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, they are difficult to meet the requirements of radio frequency front-end chips.

[0004] Surface acoustic wave resonators and radio frequency filters that still adopt traditional designs will have strong transverse mode ripples and serious passband clutter in actual applications, resulting in the deterioration of the overall device performance. Summary of the Invention

[0005] The surface acoustic wave resonator and radio frequency filter provided by the embodiments of the present invention can effectively suppress transverse mode ripples.

[0006] In a first aspect, an embodiment of the present invention provides a surface acoustic wave resonator, which includes: a substrate;

[0007] a piezoelectric layer located on the substrate;

[0008] an electrode layer, the electrode layer being located on a side of the piezoelectric layer away from the substrate;

[0009] The electrode layer includes interdigital transducers, and the interdigital transducers include: 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, there is a first gap between the first electrode fingers and the second dummy electrodes, the second electrode fingers and the first dummy electrode fingers are arranged opposite to each other, and there is a second gap between the second electrode fingers and the first dummy electrodes;

[0010] Among them, the first gaps are arranged along a first direction, the second gaps are arranged along the first direction, the included angle range between the first direction and the second direction is 2° to 15°, and in a direction parallel to the plane of the piezoelectric layer, the second direction is perpendicular to the length direction of the first electrode fingers.

[0011] Optionally, both the first electrode fingers and the second electrode fingers include a main body and a head integrally connected to the main body. The head of the first electrode finger is located on a side of the main body of the first electrode finger away from the first bus bar, and the head of the second electrode finger is located on a side of the main body of the second electrode finger away from the second bus bar;

[0012] Both the first dummy electrode fingers and the second dummy electrode fingers include a main body and a head integrally connected to the main body. The head of the first dummy electrode finger is located on a side of the main body of the first dummy electrode finger away from the first bus bar, and the head of the second dummy electrode finger is located on a side of the main body of the second dummy electrode finger away from the second bus bar;

[0013] In the second direction, the width of the head is greater than the width of the main body.

[0014] Optionally, in the second direction, the width of the head is 1.2 to 1.8 times the width of the main body.

[0015] Optionally, along the length direction of the first electrode finger, the length of the head is 0.3 to 0.7 times the wavelength of the interdigital transducer.

[0016] Optionally, the heads on the first electrode fingers are arranged opposite to the heads on the second dummy electrode fingers;

[0017] The heads on the second electrode fingers are arranged opposite to the heads on the first dummy electrode fingers.

[0018] Optionally, the electrode layer further includes a reflection grating structure;

[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 third bus bar is perpendicular to the reflection grating, and the included angle between the third bus bar and the first direction ranges from 2° to 15°, or the included angle between the third bus bar and the reflection grating ranges from 75° to 88°, and the length direction of the third bus bar is parallel to the first direction.

[0024] Optionally, along the length direction of the first electrode finger, the length of the first dummy electrode finger is 0.5 to 1.5 times the wavelength of the interdigital transducer;

[0025] The aperture of the interdigital transducer is 9 to 40 times the wavelength of the interdigital transducer.

[0026] Optionally, the piezoelectric material of the piezoelectric layer includes a positioning edge, and the positioning edge of the piezoelectric material is parallel to the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger.

[0027] 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;

[0028] A first dielectric layer, the first dielectric layer is located between the energy trap layer and the piezoelectric layer;

[0029] 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.

[0030] 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.

[0031] For the surface acoustic wave resonator provided by the embodiment of the present invention, the transverse mode ripple is adjusted by changing the included angle between the first direction and the second direction. When changing the included angle between the first direction and the second direction, the first bus bar and the second bus bar are always kept parallel, and the arrangement directions of the first gap and the second gap are always parallel to the first direction. When the included angle between the first direction and the second direction ranges from 2° to 15°, the transverse mode ripple can be effectively suppressed. The surface acoustic wave resonator provided by the embodiment of the present invention can effectively suppress the transverse mode ripple. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of a surface acoustic wave resonator provided by an embodiment of the present invention;

[0033] Figure 2 It is a schematic structural diagram of an interdigital transducer provided by an embodiment of the present invention;

[0034] Figure 3Schematic diagram of the structure of an interdigital transducer with different included angles between the first direction and the second direction;

[0035] Figure 4 Schematic diagram of the measured results of a surface acoustic wave resonator in the prior art;

[0036] Figure 5 Schematic diagram of the measured results of the surface acoustic wave resonator provided by the embodiment of the present invention;

[0037] Figure 6 Schematic diagram of the measured results of the real part of the admittance of the surface acoustic wave resonator provided by the embodiment of the present invention at different angles;

[0038] Figure 7 Schematic diagram of the measured results of the admittance amplitude of the surface acoustic wave resonator provided by the embodiment of the present invention at different angles;

[0039] Figure 8 Schematic diagram of the structure of another interdigital transducer provided by the embodiment of the present invention;

[0040] Figure 9 Schematic diagram of the top view structure of an electrode layer provided by the embodiment of the present invention;

[0041] Figure 10 Schematic diagram of the top view structure of yet another electrode layer provided by the embodiment of the present invention;

[0042] Figure 11 Schematic diagram of the top view structure of a surface acoustic wave resonator provided by the embodiment of the present invention. Detailed implementation manners

[0043] 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. Additionally, it should be noted that for the sake of description, only parts related to the embodiments of the present invention are shown in the drawings, rather than all the structures.

[0044] 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 the interdigital transducer provided by the embodiment of the present invention, referring to Figure 1 and Figure 2, the surface acoustic wave resonator includes: a substrate 110; a piezoelectric layer 120 located on the substrate 110; an electrode layer 130, the electrode layer 130 being located on the side of the piezoelectric layer 120 away from the substrate 110; the electrode layer 130 includes an interdigital transducer 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 there is a first gap 70 between the first electrode fingers 20 and the second dummy electrode 60, the second electrode fingers 50 and the first dummy electrode fingers 30 are arranged opposite to each other, and there is a second gap 80 between the second electrode fingers 50 and the first dummy electrode 30; wherein, each first gap 70 is arranged along a first direction x, each second gap 80 is arranged along the first direction x, the range of the angle θ between the first direction x and the second direction y is 2° to 15°, and in the direction parallel to the plane of the piezoelectric layer, the second direction y is perpendicular to the length direction of the first electrode fingers 20.

[0045] 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 lithium tantalate cut angle can be 30° to 50°. The thickness of the piezoelectric layer 120 can be in the range of 300 to 1000 nm. An electrode layer 130 is formed by depositing a metal film on the surface of the piezoelectric layer 120 by means such as electron beam evaporation, plasma, and magnetron sputtering. Among them, the material for depositing the metal film can be titanium, chromium, copper, silver, aluminum, etc. or a combination thereof. 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 all equal. The first bus bar 10 and the second bus bar 40 are always parallel to the first direction x, and the range of the angle θ between the first direction x and the second direction y is 2° to 15°. Figure 3 is a schematic structural diagram of an interdigital transducer with different angles between the first direction and the second direction. Refer to Figure 3 , Figure 3 in which the solid line represents a schematic structural diagram of an interdigital transducer with an angle of 0° between the first direction x and the second direction y. Figure 3 in which the dotted line represents a schematic structural diagram with an angle of θ between the first direction x and the second direction y, wherein the angle θ between the first direction x and the second direction y is in the range of 2° to 15°. From Figure 3As can be seen, when the included angle θ between the first direction x and the second direction y is within the range of 2° to 15°, the first bus bar 10 is inclined, and the inclination angle of the first bus bar 10 is equal to the included angle θ between the first direction x and the second direction y. When the first bus bar 10 is inclined, the size and direction of the first electrode finger 20 remain unchanged. Figure 4 It is a schematic diagram of the measured results of a surface acoustic wave resonator in the prior art. Refer to Figure 4 , Figure 4 One of the curves in represents a schematic diagram of the relationship between the real part of admittance and frequency. Figure 4 The other curve in represents a schematic diagram of the relationship between the magnitude of admittance and frequency. It can be clearly seen from Figure 4 that there are serious transverse mode ripples in the measured results of the surface acoustic wave resonator designed by the prior art. In particular, the transverse mode ripples in the curve of the relationship between the real part of admittance and frequency include ripples a1 - a7. In practical applications, the generation of multiple transverse mode ripples is not suitable for the generation of filters. Figure 5 It is a schematic diagram of the measured results of the surface acoustic wave resonator provided by an embodiment of the present invention. Refer to Figure 5 , in Figure 4 the transverse mode ripples a1 - a7 that appear do not appear in Figure 5 . It can be seen that the surface acoustic wave resonator provided by the embodiment of the present invention can effectively suppress the transverse ripples. Figure 6 It is a schematic diagram of the measured results of the real part of admittance of the surface acoustic wave resonator provided by an embodiment of the present invention at different angles. Figure 7 It is a schematic diagram of the measured results of the magnitude of admittance of the surface acoustic wave resonator provided by an embodiment of the present invention at different angles. Refer to Figure 6 and Figure 7 , add a certain dB value to the vertical coordinate to make the schematic diagram of the measured results look more intuitive. When the included angle between the first direction and the second direction is 0°, serious transverse mode ripples appear. When the included angles between the first direction and the second direction are 3°, 5°, 7° and 11° respectively, the transverse mode ripples can be effectively suppressed. Preferably, when the included angle between the first direction and the second direction is more than 3°, the suppression effect of the transverse mode ripples is more obvious. It should be noted that in the embodiment of the present invention, the arrangement direction of the first gap is denoted as the first direction. In fact, the connection direction of the aperture center points of the first electrode fingers is also the first direction, and the connection of the aperture center points of the second electrode fingers is also the first direction. When changing the included angle between the first direction and the second direction, the lengths, widths and directions of the first electrode fingers, the second electrode fingers, the first dummy electrode fingers and the second dummy electrode fingers remain unchanged.

[0046] The surface acoustic wave resonator provided by the embodiment of the present invention adjusts the transverse mode ripple by changing the included angle between the first direction and the second direction. When changing the included angle between the first direction and the second direction, the first bus bar and the second bus bar are always kept parallel, the arrangement direction of the first gap and the arrangement direction of the second gap are always parallel to the first direction. When the included angle range between the first direction and the second direction is 2° to 15°, the transverse mode ripple can be effectively suppressed. The surface acoustic wave resonator provided by the embodiment of the present invention can effectively suppress the transverse mode ripple.

[0047] Optionally, Figure 8 is a schematic structural diagram of another interdigital transducer provided by the embodiment of the present invention. Refer to Figure 8 , both the first electrode finger 20 and the second electrode finger 50 include a main body 11 and a head 12 integrally connected to the main body 11. The head 12 of the first electrode finger 20 is located on the side of the main body 11 of the first electrode finger 20 away from the first bus bar 10, and the head 12 of the second electrode finger 50 is located on the side of the main body 11 of the second electrode finger 50 away from the second bus bar 40; both the first dummy electrode finger 30 and the second dummy electrode finger 60 include a main body 11 and a head 12 integrally connected to the main body 11. The head 12 of the first dummy electrode finger 30 is located on the side of the main body 11 of the first dummy electrode finger 30 away from the first bus bar 10, and the head 12 of the second dummy electrode finger 60 is located on the side of the main body 11 of the second dummy electrode finger 60 away from the second bus bar 40; in the second direction y, the width of the head 12 is greater than the width of the main body 11.

[0048] Specifically, the propagation direction of the surface acoustic wave is parallel to the second direction y. Setting the width of the head 12 to be greater than the width of the main body 11 can enable the head 12 to block the leakage of 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 8 only exemplarily shows that the shape of the head is a rectangle, and the shape of the head can also be a triangle or a polygon.

[0049] Optionally, in the second direction, the width of the head is 1.2 to 1.8 times the width of the main body.

[0050] Specifically, setting the width of the head to be 1.2 to 1.8 times the width of the main body can further enable the head to block the leakage of 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.

[0051] Optionally, along the length direction of the first electrode finger, the length of the head is 0.3 to 0.7 times the wavelength of the interdigital transducer.

[0052] Specifically, setting the length of the end portion in the length direction of the first electrode finger to 0.3 to 0.7 times the wavelength of the interdigital transducer can further prevent the end portion from blocking the leakage of 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.

[0053] Optionally, continue to refer to Figure 8 , the end portion 12 on the first electrode finger 20 is disposed opposite to the end portion 12 on the second dummy electrode finger 60; the end portion 12 on the second electrode finger 50 is disposed opposite to the end portion 12 on the first dummy electrode finger 30.

[0054] Specifically, disposing the end portion 12 on the first electrode finger 20 opposite to the end portion 12 on the second dummy electrode finger 60, and disposing the end portion 12 on the second electrode finger 50 opposite to the end portion 12 on the first dummy electrode finger 30 can further prevent the end portion 12 from blocking the leakage of 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.

[0055] Optionally, Figure 9 is a top view structural schematic diagram of an electrode layer provided by an embodiment of the present invention, Figure 10 is another top view structural schematic diagram of an electrode layer provided by an embodiment of the present invention. Refer to Figure 9 and Figure 10 , the electrode layer further includes a reflection grating structure 132; the reflection grating structure 132 includes a third bus bar 90, a fourth bus bar 91, and a plurality of reflection gratings 92; the third bus bar 90 and the fourth bus bar 91 are arranged in parallel; the first end of the reflection grating 92 is connected to the third bus bar 90, and the second end of the reflection grating 92 is connected to the fourth bus bar 91; along the length direction of the first bus bar 10, the reflection grating structure 132 is located on both sides of the interdigital transducer 131; the third bus bar 90 is perpendicular to the reflection grating 92 and the included angle between the third bus bar 90 and the first direction x ranges from 2 to 15° or the included angle between the third bus bar 90 and the reflection grating 92 ranges from 75° to 88° and the length direction of the third bus bar 90 is parallel to the first direction x.

[0056] Specifically, Figure 9 in the reflection grating structure 132 in , the third bus bar 90 is perpendicular to the reflection grating 92 and the included angle between the third bus bar 90 and the first direction x ranges from 2 to 15°, and the included angle between the third bus bar 90 and the first direction x is equal to the included angle between the first direction x and the second direction y. Figure 10The third bus bar 90 therein is parallel to the first direction x, and the angle between the third bus bar 90 and the second direction y is equal to the angle between the first direction x and the second direction y. When the angle between the first direction x and the second direction is θ, the angle between the third bus bar 90 and the reflection grating 92 is 90 - θ. Since the range of the angle θ between the first direction x and the second direction y is 2° to 15°, the range of the angle between the third bus bar 90 and the reflection grating 92 is 75° to 88°. The reflection grating structure 132 can reflect the energy of the surface acoustic wave and concentrate the energy in the interdigital transducer 131. In the embodiment of the present invention, the reflection grating 92 is always set parallel to the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger, further ensuring that the reflection grating structure 132 concentrates the energy of the reflected surface acoustic wave into the interdigital transducer 131, and further improving the Q value of the surface acoustic wave resonator. Wherein, the number of the reflection gratings 92 in each reflection grating structure 132 is 15 to 30. It should be noted that, Figure 9 and Figure 10 the interdigital transducers in all include the ends integrally connected to the main body. In fact, the interdigital transducers in the electrode layer may not include the ends integrally connected to the main body.

[0057] Optionally, along the length direction of the first electrode finger, the length of the first dummy electrode finger is 0.5 to 1.5 times the wavelength of the interdigital transducer; the aperture of the interdigital transducer is 9 to 40 times the wavelength of the interdigital transducer.

[0058] Specifically, setting the length of the first dummy electrode finger to be 0.5 to 1.5 times the wavelength of the interdigital transducer and setting the aperture of the interdigital transducer to be 9 to 40 times the wavelength of the interdigital transducer can further make the improvement of the Q value of the surface acoustic wave resonator more obvious.

[0059] Optionally, Figure 11 is a top view structural schematic diagram of a surface acoustic wave resonator provided by an embodiment of the present invention. Refer to Figure 11 , the piezoelectric material of the piezoelectric layer 120 includes a positioning edge 121, and the positioning edge 121 of the piezoelectric material is parallel to the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger.

[0060] Specifically, by setting the positioning edge 121 in the piezoelectric material and making the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger in each interdigital transducer parallel to the positioning edge 121, each interdigital transducer in the electrode layer can be arranged parallel to each other. Since the propagation direction of the surface acoustic wave is perpendicular to the positioning edge 121, each of the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger in the interdigital transducer can block the leakage of the transverse energy in the surface acoustic wave, better suppressing the clutter in the surface acoustic wave, and further improving the Q value of the surface acoustic wave resonator.

[0061] 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.

[0062] 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 and further improve the Q value of the surface acoustic wave resonator. A low sound velocity silicon dioxide layer is grown on the side of the energy trap layer 140 away from the substrate 110 by means of plasma enhanced chemical vapor deposition or thermal oxidation of silicon, so as to form 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 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 constitute a composite multi-layer substrate. The composite multi-layer substrate in the embodiment of the present invention can enable the surface acoustic wave resonator and the radio frequency filter to achieve characteristics such as low insertion loss, smooth passband, high Q value and excellent low frequency temperature.

[0063] 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.

[0064] Specifically, the radio frequency filter provided by the embodiment of the present invention has corresponding beneficial effects with the surface acoustic wave resonator provided by any embodiment of the present invention. The technical details not elaborated in this embodiment are elaborated in the surface acoustic wave resonator provided by any embodiment of the present invention.

[0065] Note that the above is only the preferred embodiment of the embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the embodiment of the present invention is 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 embodiment of the present invention. Therefore, although the embodiment of the present invention has been described in more detail through the above embodiments, the embodiment of the present invention is not limited to the above embodiments only. Without departing from the concept of the embodiment of the present invention, more other equivalent embodiments can be included, and the scope of the embodiment 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 located on a side of the piezoelectric layer away from the substrate; The electrode layer includes interdigital transducers, and the interdigital transducers include: 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 oppositely arranged, there is a first gap between the first electrode fingers and the second dummy electrodes, the second electrode fingers and the first dummy electrode fingers are oppositely arranged, and there is a second gap between the second electrode fingers and the first dummy electrodes; Wherein, each of the first gaps is arranged along a first direction, each of the second gaps is arranged along the first direction, the included angle range between the first direction and a second direction is 2 to 15°, and in a direction parallel to the plane of the piezoelectric layer, the second direction is perpendicular to the length direction of the first electrode fingers; the first bus bar is parallel to the second bus bar; When changing the included angle between the first direction and the second direction, the lengths, widths and directions of the first electrode fingers, the second electrode fingers, the first dummy electrode fingers and the second dummy electrode fingers remain unchanged.

2. The surface acoustic wave resonator according to claim 1, wherein Both the first electrode fingers and the second electrode fingers include a main body and a head integrally connected to the main body, the head of the first electrode finger is located on a side of the main body of the first electrode finger away from the first bus bar, and the head of the second electrode finger is located on a side of the main body of the second electrode finger away from the second bus bar; Both the first dummy electrode fingers and the second dummy electrode fingers include a main body and a head integrally connected to the main body, the head of the first dummy electrode finger is located on a side of the main body of the first dummy electrode finger away from the first bus bar, and the head of the second dummy electrode finger is located on a side of the main body of the second dummy electrode finger away from the second bus bar; In the second direction, the width of the head is greater than the width of the main body.

3. The surface acoustic wave resonator according to claim 2, wherein In the second direction, the width of the head is 1.2 to 1.8 times the width of the main body.

4. The resonator according to claim 2, wherein Along the length direction of the first electrode finger, the length of the head is 0.3 to 0.7 times the wavelength of the interdigital transducer.

5. The resonator according to claim 2, characterized in that, The heads on the first electrode fingers are oppositely arranged with the heads on the second dummy electrode fingers; The heads on the second electrode fingers are oppositely arranged with the heads on the first dummy electrode fingers.

6. The surface acoustic wave resonator according to claim 1, wherein The electrode layer further includes a reflection grating structure; 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 third bus bar is perpendicular to the reflection grating, and the included angle between the third bus bar and the first direction ranges from 2° to 15°, or the included angle between the third bus bar and the reflection grating ranges from 75° to 88°, and the length direction of the third bus bar is parallel to the first direction.

7. The surface acoustic wave resonator according to claim 2, wherein Along the length direction of the first electrode finger, the length of the first dummy electrode finger is 0.5 to 1.5 times the wavelength of the interdigital transducer. The aperture of the interdigital transducer is 9 to 40 times the wavelength of the interdigital transducer.

8. The surface acoustic wave resonator according to claim 1, wherein The piezoelectric material of the piezoelectric layer includes a positioning edge, and the positioning edge of the piezoelectric material is parallel to the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger.

9. The surface acoustic wave resonator according to claim 1, wherein 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, and the first dielectric layer is located between the energy trap layer and the piezoelectric layer. A second dielectric layer, and the second dielectric layer is located on the side of the electrode layer away from the piezoelectric layer and covers the electrode layer.

10. A radio frequency filter, characterized in that, It includes the surface acoustic wave resonator according to any one of claims 1-9.

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