A surface acoustic wave resonator, filter, and electronic device

Abstract

The application discloses a surface acoustic wave resonator, a filter and an electronic device, and relates to the field of resonators.The surface acoustic wave resonator comprises a piezoelectric substrate for sound-electric energy conversion;an interdigital electrode arranged on one side surface of the piezoelectric substrate and used for exciting the piezoelectric substrate to perform sound-electric energy conversion by applying a voltage;the interdigital electrode comprises first finger strips and second finger strips arranged alternately in a first direction;the first finger strips and the second finger strips both extend along a second direction;two reflection gratings are arranged on the same side surface of the piezoelectric substrate as the interdigital electrode, and the interdigital electrode is located between the two reflection gratings in the first direction;the reflection gratings comprise a plurality of reflection grating strips arranged in sequence along the first direction;in the same reflection grating, each reflection grating strip has regularly distributed gaps, and the gaps are used for reducing bulk waves of the surface acoustic wave resonator.The application can reduce the insertion loss of the surface acoustic wave resonator through the regularly distributed gaps in the reflection grating.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of resonators, in particular to a surface acoustic wave resonator, a filter and an electronic device. BACKGROUND

[0002] A surface acoustic wave resonator (SAW) is a device widely used in the field of radio frequency, which has low insertion loss and good suppression performance, and is also small in size. The surface acoustic wave resonator mainly utilizes the piezoelectric effect to convert electrical energy and mechanical energy. The surface acoustic wave resonator can be used to combine the gating characteristics of signal transmission.

[0003] The surface acoustic wave resonator can be connected based on a set circuit topology to form a filter. The surface acoustic wave resonator mainly includes a piezoelectric substrate and an interdigital electrode on the surface of the piezoelectric substrate. The interdigital electrode can excite the piezoelectric substrate to perform acoustic-electric conversion by applying a voltage.

[0004] The insertion loss of the conventional surface acoustic wave resonator is serious. How to reduce the insertion loss of the surface acoustic wave resonator is a problem to be solved in the field of resonators. SUMMARY

[0005] In view of the above problems, the present application provides a surface acoustic wave resonator, a filter and an electronic device to achieve the purpose of reducing the insertion loss of the surface acoustic wave resonator. The specific scheme is as follows:

[0006] The first aspect of the present application provides a surface acoustic wave resonator, comprising:

[0007] a piezoelectric substrate, the piezoelectric substrate being used for acoustic-electric conversion;

[0008] an interdigital electrode, the interdigital electrode being arranged on one side surface of the piezoelectric substrate and being used for exciting the piezoelectric substrate to perform acoustic-electric conversion by applying a voltage; the interdigital electrode comprises first fingers and second fingers which are arranged alternately in a first direction; the first fingers and the second fingers both extend along a second direction, and the first direction and the second direction intersect on a plane parallel to the piezoelectric substrate;

[0009] two reflective gratings, the reflective gratings being arranged on the same side surface of the piezoelectric substrate as the interdigital electrode, and in the first direction, the interdigital electrode is located between the two reflective gratings;

[0010] wherein the reflective grating comprises a plurality of reflective grating fingers arranged in sequence along the first direction; in the direction away from the interdigital electrode, the plurality of reflective grating fingers are sequentially the first reflective grating finger to the Nth reflective grating finger, N is a positive integer greater than 1;

[0011] For the same reflective grating, in the 1st reflective grating finger to the nth reflective grating finger, the 2i-1th reflective grating finger has a slit located on the first reference line, and the 2ith reflective grating finger has a slit located on the second reference line, the first reference line intersects the second reference line, and the intersection position is located on the side of the 1st reflective grating finger away from the interdigital electrode; wherein n is a positive integer not greater than N; i is a positive integer, and 2i is not greater than n.

[0012] Optionally, in the above surface acoustic wave resonator, n=N; the intersection position of the first reference line and the second reference line is located on the Nth reflective grating finger.

[0013] Optionally, in the above surface acoustic wave resonator, n=N; the intersection position of the first reference line and the second reference line is located on the side away from the interdigital electrode outside the Nth reflective grating finger.

[0014] Optionally, in the above surface acoustic wave resonator, the first reference line and the second reference line have equal angles with the first direction.

[0015] Optionally, in the above surface acoustic wave resonator, n

[0016] For the same reflective grating, in the nth reflective grating finger to the Nth reflective grating finger, the 2j-1th reflective grating finger has a slit located on the third reference line, and the 2jth reflective grating finger has a slit located on the fourth reference line, the third reference line intersects the fourth reference line, and the intersection position is located on the side of the nth reflective grating finger towards the interdigital electrode; wherein j is a positive integer; 2j-1 is not less than n, and 2j is not greater than N.

[0017] Optionally, in the above surface acoustic wave resonator, the first reference line and the third reference line have equal angles with the first direction.

[0018] The second reference line and the fourth reference line have equal angles with the first direction.

[0019] Optionally, in the above surface acoustic wave resonator, in the 1st reflective grating finger to the nth reflective grating finger, the reflective grating fingers are equally distributed with a first line spacing;

[0020] In the nth reflective grating finger to the Nth reflective grating finger, the reflective grating fingers are equally distributed with a second line spacing;

[0021] Wherein, the first line spacing and the second line spacing are different.

[0022] Optionally, in the above surface acoustic wave resonator, the reflective grating has oppositely arranged first bus bars and second bus bars;

[0023] The same reflective grating is provided with a slit, and the slit divides the reflective grating finger into a first reflective grating finger segment and a second reflective grating finger segment opposite to each other; the first reflective grating finger segment is located between the slit and the first bus bar and is integrally connected with the first bus bar; and the second reflective grating finger segment is located between the slit and the second bus bar and is integrally connected with the second bus bar.

[0024] Optionally, in the above-described surface acoustic wave resonator, in the same reflective grating, along a direction away from the interdigital electrode, the plurality of reflective grating fingers are sequentially the first reflective grating finger to the Nth reflective grating finger, N is a positive integer greater than 1.

[0025] In the first reflective grating finger to the (N-1)th reflective grating finger, each reflective grating finger is provided with two slits, and the reflective grating finger segment between the two slits is a floating electrode; wherein, in the same reflective grating, along a direction away from the interdigital electrode, lengths of the floating electrodes sequentially decrease, or the lengths of the floating electrodes sequentially decrease and then sequentially increase.

[0026] The second aspect of the present application provides a filter comprising the surface acoustic wave resonator of any one of the above.

[0027] The third aspect of the present application provides an electronic device comprising the filter.

[0028] Through the above technical solutions, the surface acoustic wave resonator, the filter and the electronic device provided by the present application are provided. The surface acoustic wave resonator is provided with an interdigital electrode on the same side surface of a piezoelectric substrate, and the interdigital electrode is provided with a reflective grating on opposite sides in a first direction. The reflective grating finger of the reflective grating is provided with regularly distributed slits. The regularly distributed slits in the reflective grating finger can reduce the bulk wave of the surface acoustic wave resonator, thereby reducing the insertion loss of the surface acoustic wave resonator and improving the performance of the surface acoustic wave resonator. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments or the related art, the drawings needed in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can obtain other drawings according to the provided drawings without creative labor.

[0030] The structure, proportion, size and the like shown in the drawings of the specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and do not have technical substantive significance, and any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0031] Figure 1 A passband curve diagram of a surface acoustic wave resonator with a reflection grating;

[0032] Figure 2 A top view of a surface acoustic wave resonator provided by an embodiment of the present application;

[0033] Figure 3 A top view of a reflection grating provided by an embodiment of the present application;

[0034] Figure 4 A top view of another reflection grating provided by an embodiment of the present application;

[0035] Figure 5 A top view of still another reflection grating provided by an embodiment of the present application;

[0036] Figure 6 A top view of still another reflection grating provided by an embodiment of the present application;

[0037] Figure 7 A top view of still another reflection grating provided by an embodiment of the present application;

[0038] Figure 8 A top view of still another reflection grating provided by an embodiment of the present application;

[0039] Figure 9 A top view of still another reflection grating provided by an embodiment of the present application;

[0040] Figure 10 A top view of still another reflection grating provided by an embodiment of the present application;

[0041] Figure 11 A top view of still another reflection grating provided by an embodiment of the present application;

[0042] Figure 12 A passband curve diagram of a surface acoustic wave resonator provided by an embodiment of the present application;

[0043] Figure 13 A passband curve diagram of another surface acoustic wave resonator provided by an embodiment of the present application;

[0044] Figure 14The embodiment of the present application provides another admittance curve diagram of the surface acoustic wave resonator.

[0045] Figure 15 The embodiment of the present application provides a passband curve diagram of the surface acoustic wave resonator.

[0046] Reference signs:

[0047] 11-piezoelectric substrate; 12-interdigital electrode; 121-first finger; 122-second finger; 123-third bus bar; 124-fourth bus bar; 13-reflective grating; 131-first bus bar; 132-second bus bar; 133-gap; GL-reflective grating finger; GL'-floating electrode; L1-first reference line; L2-second reference line; L3-third reference line; L4-fourth reference line. DETAILED DESCRIPTION

[0048] The embodiments in the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. It can be known by those skilled in the art that, with the development of technology and the appearance of new scenes, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0049] Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application. The terms used in the embodiments of the present application are only used for explaining the specific embodiments of the present application, and are not intended to limit the present application.

[0050] The surface acoustic wave resonator can prepare a reflective grating on the surface of the piezoelectric substrate on both sides of the interdigital electrode, and the surface acoustic wave resonator can reflect the sound wave through the reflective grating to form better resonance, thereby improving the transmission performance of the resonator. In the conventional surface acoustic wave resonator, although the transmission performance of the resonator can be improved through the reflective grating, the conventional reflective grating mainly has the function of reflecting the sound wave, and cannot solve the problem of high insertion loss of the surface acoustic wave resonator.

[0051] If the insertion loss of the SAW resonator is serious, the application of the SAW resonator will be limited. For example, when the SAW resonator can be connected to form a filter based on a set circuit topology, at this time, the method of connecting the resonators in series (characterized by large aperture and large number of IDTs) can be used to improve the steepness of the frequency response curve of the filter. The steeper the frequency response curve of the filter, the narrower the transition band of the cutoff frequency, and the better the performance of the filter. However, when improving the steepness of the frequency response curve, the passband insertion loss of the resonator will be deteriorated. This is because when improving the steepness of the frequency response curve of the filter, if the bulk wave of the SAW resonator falls into the passband, the passband insertion loss will be deteriorated. Experimental results show that the deterioration of the passband insertion loss can be as high as 0.8 dB.

[0052] Reference Figure 1 , Figure 1 is a passband curve diagram of a SAW resonator with a reflector, the horizontal axis is frequency, unit is GHz, and the vertical axis is signal power, unit is dB. The passband performance of the filter is easily affected by the bulk wave of the SAW resonator. The problem is that when the bulk wave of the SAW resonator falls into the passband, as shown by the dashed oval area in Figure 1 , the passband curve of the SAW resonator will collapse.

[0053] Generally, avoiding the bulk wave of the SAW resonator from falling into the passband or weakening the bulk wave of the SAW resonator are two effective methods to reduce the insertion loss of the SAW resonator and improve its performance.

[0054] The inventors have found that by adjusting the design parameters of the reflector and setting the length of the reflector IDT in the reflector to vary regularly, the bulk wave of the SAW resonator can be reduced and / or the bulk wave of the SAW resonator can be located outside the passband of the SAW resonator, thereby effectively reducing the insertion loss of the SAW resonator without affecting the passband performance of the resonator.

[0055] Based on this, the embodiments of the present application provide a SAW resonator, comprising:

[0056] a piezoelectric substrate, the piezoelectric substrate being used for acoustic-electric energy conversion;

[0057] an interdigital electrode, the interdigital electrode being arranged on one side surface of the piezoelectric substrate and being used for exciting the piezoelectric substrate to perform acoustic-electric energy conversion by applying a voltage; the interdigital electrode comprises first IDTs and second IDTs arranged alternately in a first direction; the first IDTs and the second IDTs both extend along a second direction, and the first direction and the second direction intersect on a plane parallel to the piezoelectric substrate;

[0058] two reflective gratings, the reflective gratings and the interdigital electrode are disposed on the same side surface of the piezoelectric substrate, and in the first direction, the interdigital electrode is located between the two reflective gratings;

[0059] The reflective gratings comprise a plurality of reflective grating strips arranged in sequence along the first direction, and the plurality of reflective grating strips are sequentially the first reflective grating strip to the Nth reflective grating strip in a direction away from the interdigital electrode, N being a positive integer greater than 1.

[0060] For the same reflective gratings, in the first reflective grating strip to the nth reflective grating strip, the (2i-1)th reflective grating strip has a gap located on the first reference line, and the 2ith reflective grating strip has a gap located on the second reference line, the first reference line intersects the second reference line, and the intersection position is located on the side of the first reflective grating strip away from the interdigital electrode; wherein n is a positive integer not greater than N; i is a positive integer, and 2i is not greater than n.

[0061] In the surface acoustic wave resonator provided in the embodiments of the present application, regularly distributed gaps are arranged in the reflective gratings, and the regularly distributed gaps in the reflective grating strips can reduce the bulk wave of the surface acoustic wave resonator, thereby reducing the insertion loss of the surface acoustic wave resonator and improving the performance of the surface acoustic wave resonator.

[0062] The above is the core inventive concept of the technical scheme of the present application, in order to make the above-mentioned purposes, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0063] Reference Figure 2 As shown, Figure 2 A top view of a surface acoustic wave resonator provided by an embodiment of the present application is shown, and the surface acoustic wave resonator comprises:

[0064] A piezoelectric substrate 11, the piezoelectric substrate 11 is used for acoustic-electric conversion;

[0065] An interdigital electrode 12, the interdigital electrode 12 is disposed on one side surface of the piezoelectric substrate 11, and is used for exciting the piezoelectric substrate 11 to perform acoustic-electric conversion by applying a voltage; the interdigital electrode 12 comprises first fingers 121 and second fingers 122 arranged alternately in a first direction X; the first fingers 121 and the second fingers 122 both extend along a second direction Y, and the first direction X and the second direction Y intersect in a plane parallel to the plane in which the piezoelectric substrate 11 is located;

[0066] Two reflective gratings 13, the reflective gratings 13 and the interdigital electrode 12 are disposed on the same side surface of the piezoelectric substrate 11, and in the first direction X, the interdigital electrode 12 is located between the two reflective gratings 13;

[0067] The reflection grating 13 includes a plurality of reflection grating fingers GL arranged in sequence along the first direction X. In the same reflection grating 13, each reflection grating finger GL has regularly distributed gaps 133 for reducing the bulk wave of the surface acoustic wave resonator.

[0068] In the surface acoustic wave resonator provided by the embodiment of the present application, without adding new structures, the gaps 133 provided in the reflection grating fingers GL of the reflection grating 13 can reduce the bulk wave of the surface acoustic wave resonator, thereby effectively reducing the insertion loss of the surface acoustic wave resonator, without affecting the passband performance of the resonator, and the manufacturing method is simple, compatible with the existing manufacturing method of the surface acoustic wave resonator, and has low manufacturing cost.

[0069] The reflection grating 13 has a plurality of reflection grating fingers GL arranged in sequence along the first direction X. The reflection grating 13 further includes a first bus bar 131 and a second bus bar 132 opposite to each other in the second direction Y. The two ends of the reflection grating finger GL opposite to each other in the second direction Y can be integrally connected with the first bus bar 131 and the second bus bar 132, respectively.

[0070] The first bus bar 131 and the second bus bar 132 can be straight lines parallel to each other as shown in Figure 2 Other modes can be broken line structures or curve structures, and the embodiment of the present application does not limit the graphic structure of the first bus bar 131 and the second bus bar 132.

[0071] Optionally, the interdigital electrode 12 includes a first interdigital electrode and a second interdigital electrode nested with each other. The first interdigital electrode includes the third bus bar 123 and all the first fingers 121. The second interdigital electrode includes the fourth bus bar 124 and all the second fingers 122.

[0072] The first finger 121 has a gap with the fourth bus bar 124 at one end thereof facing the fourth bus bar 124, so as to be disconnected with the fourth bus bar 124. The second finger 122 has a gap with the third bus bar 123 at one end thereof facing the third bus bar 123, so as to be disconnected with the third bus bar 123.

[0073] The first finger 121 and the second finger 122 can be straight lines, broken lines or curve structures, and the embodiment of the present application does not limit the graphic structure of the first finger 121 and the second finger 122.

[0074] The third bus bar 123 and the fourth bus bar 124 are arranged opposite to each other in the second direction Y. The third bus bar 123 and the fourth bus bar 124 can be straight lines parallel to each other as shown in Figure 2The diagram shows a parallel straight line structure. In other cases, the two lines can be a broken line structure or a curved structure. This application embodiment does not limit the graphic structure of the third bus bar 123 and the fourth bus bar 124.

[0075] refer to Figure 3 , Figure 3 This is a top view of a reflective grating provided in an embodiment of this application, wherein, in combination with Figure 2 and Figure 3 As shown, for the same reflective grating 13, along the direction away from the interdigitated electrode 12, the multiple reflective grating fingers GL are sequentially the first reflective grating finger GL1 to the Nth reflective grating finger GL. N N is a positive integer greater than 1. The first reflective grating bar GL1 is arranged adjacent to the interdigitated electrode 12, and the other reflective grating bars GL are arranged sequentially on the side of the first reflective grating bar GL1 away from the interdigitated electrode 12.

[0076] Figure 3 Taking the reflective grating 13 located on the side of the interdigitated electrode 12 away from the first direction X as an example, its direction away from the interdigitated electrode 12 is the opposite direction of the first direction X. If the reflective grating 13 is located on the side of the interdigitated electrode 12 facing the first direction X, its direction away from the interdigitated electrode 12 is the positive direction of the first direction X.

[0077] In this embodiment, the number of reflective grating fingers GL in the reflective grating 13 can be set according to requirements, and is not limited to... Figure 3 The N=11 shown can be any positive integer greater than 1.

[0078] In the embodiments of this application, such as Figure 3 As shown, for the same reflective grating 13, from the first reflective grating finger GL1 to the nth reflective grating finger GL... n In the middle, the 2i-1th reflective grating finger GL 2i-1 All have a slot 133 located on the first reference line L1, and a second i-th reflective grating finger GL. 2i Each has a gap 133 located on the second reference line L2. The first reference line L1 intersects the second reference line L2, and the intersection position Q1 is located on the side of the first reflective grating finger GL1 away from the interdigitated electrode 12. Here, n is a positive integer not greater than N; i is a positive integer, and 2i is not greater than n.

[0079] In this embodiment, each reference line is used to indicate the layout position of the gap 133 in the reflective grating 13, and is not an actual line structure that actually exists in the reflective grating 13.

[0080] From the first reflective grating finger GL1 to the nth reflective grating finger GL nIn the embodiment, the first reference line L1 and the second reference line L2 can form an envelope line, and the sound wave leaked from the interdigital electrode 12 needs to leak out of the envelope line in the reflection grating 13. Since the gaps 133 constituting the envelope line are regularly staggered in the reflection grating 13, the sound wave leaked out becomes less and less in the direction away from the interdigital electrode 12. Moreover, the sound wave is reflected and refracted for many times between the reflection grating fingers GL, and the energy is continuously reduced, so that the performance curve of the surface acoustic wave resonator becomes flat, the difference between the body wave peak and the valley is reduced, the body wave of the surface acoustic wave resonator is reduced, and the insertion loss is reduced.

[0081] In an embodiment of the present application, as shown in Figure 3 , n=N; the intersection position Q1 of the first reference line L1 and the second reference line L2 is located on the Nth reflection grating finger GL N , and n=N; the intersection position Q1 of the first reference line L1 and the second reference line L2 is located on the Nth reflection grating finger GL 11 .

[0082] If n=N, the intersection position Q1 of the two reference lines is located on the Nth reflection grating finger GL N , the first reference line L1 and the second reference line L2 can form a conical envelope region in the reflection grating 13, the bottom edge of the conical envelope region is directed to the interdigital electrode 12, and the tip is away from the interdigital electrode 12. On the one hand, in the direction away from the interdigital electrode 12, the length of the reflection grating finger segment of each reflection grating finger GL in the envelope region decreases in turn, which can reduce the body wave and thus reduce the insertion loss of the surface acoustic wave resonator; on the other hand, the conical envelope region formed by the reflection grating finger segments can also make the reflection grating 13 have a relatively uniform reflectivity.

[0083] Reference Figure 4 , Figure 4 is another top view of the reflection grating provided by the embodiment of the present application, and in this mode, n=N, which is different from the mode shown in Figure 3 . As shown in Figure 2 and Figure 4 , the intersection position Q1 of the first reference line L1 and the second reference line L2 is located on the side of the Nth reflection grating finger GL N away from the interdigital electrode 12.

[0084] In Figure 4In the illustrated configuration, the first reference line L1 and the second reference line L2 can form a trapezoidal envelope region within the reflective grating 13. The long base of the trapezoidal envelope region faces the interdigitated electrode 12, while the short base is away from the interdigitated electrode 12. On one hand, along the direction away from the interdigitated electrode 12, the length of each reflective grating finger GL segment within this envelope region decreases sequentially, which can reduce bulk waves and thus reduce the insertion loss of the surface acoustic wave resonator. On the other hand, the trapezoidal envelope region constructed by each reflective grating finger segment also allows the reflective grating 13 to better concentrate acoustic wave energy.

[0085] In one embodiment of this application, the angles between the first reference line L1 and the second reference line L2 and the first direction X are equal. For example, in... Figure 3 In the configuration shown, the angles between the first reference line L1 and the second reference line L2 and the first direction X are both α; as shown... Figure 4 In the configuration shown, the angle between the first reference line L1 and the second reference line L2 and the first direction X is both b.

[0086] If the angles between the first reference line L1 and the second reference line L2 and the first direction X are equal, it will facilitate the layout design of the slot 133 in the reflective grating 13 and simplify the fabrication process of the reflective grating 13.

[0087] In other ways, it is also possible to... Figure 5 and Figure 6 As shown, the angles between the first reference line L1 and the second reference line L2 and the first direction X are not equal.

[0088] refer to Figure 5 , Figure 5 A top view of another reflective grating provided in an embodiment of this application, and... Figure 3 The difference shown is that, Figure 5 In the reflective grating 13 shown, the angles between the first reference line L1 and the second reference line L2 and the first direction X are not equal. The angle between the first reference line L1 and the first direction X is a1, and the angle between the second reference line L2 and the first direction X is a2. Wherein, a1≠a2.

[0089] refer to Figure 6 , Figure 6 A top view of another reflective grating provided in an embodiment of this application, and... Figure 4 The difference shown is that, Figure 6 In the reflective grating 13 shown, the angles between the first reference line L1 and the second reference line L2 and the first direction X are not equal. The angle between the first reference line L1 and the first direction X is b1, and the angle between the second reference line L2 and the first direction X is b2. Wherein, b1≠b2.

[0090] If the angles between the first reference line L1 and the second reference line L2 and the first direction X are not equal, the reflection performance and volume wave reduction capability of the reflective grating 13 can be adjusted more flexibly, and the reflection performance and volume wave reduction capability can be optimized more easily through the reflective grating 13.

[0091] In this embodiment, the reference line can be a straight line or an arc. If the reference line is an arc, at the intersection of two reference lines, the angle between the reference line and the first direction X or the second direction Y is the angle between the tangent of the arc at the intersection and the first direction X or the second direction Y.

[0092] refer to Figure 7 , Figure 7 This is a top view of another reflective grating provided in an embodiment of this application. Based on the above implementation, if n < N, as... Figure 7 As shown, for the same reflective grating 13, from the first reflective grating finger GL1 to the nth reflective grating finger GL... n In the middle, the 2i-1th reflective grating finger GL 2i-1 All have a slot 133 located on the first reference line L1, and a second i-th reflective grating finger GL. 2i All have a gap 133 located on the second reference line L2, the first reference line L1 intersects the second reference line L2, and the intersection position Q1 is located at the nth reflective grating finger GL. n On the side away from the interdigitated electrode 12, i is a positive integer, and 2i is not greater than n; on the nth reflective grating finger GL n Up to the Nth reflective grating finger GL N In the middle, the 2j-1st reflective grating finger GL 2j-1 All have a slot 133 located on the third reference line L3, and the second j-th reflective grating finger GL. 2j All have a gap 133 located on the fourth reference line L4, the third reference line L3 intersects the fourth reference line L4, and the intersection position Q2 is located on the nth reflective grating finger GL. n On the side facing the interdigitated electrode 12, j is a positive integer, 2j-1 is not less than n, and 2j is not greater than N.

[0093] If n is odd, then the intersection of the first reference line L1 and the third reference line L3 is located at the nth reflective grating finger GL. n The intersection of the gap 133, the second reference line L2, and the fourth reference line L4 is located at the (n-1)th reflective grating finger GL. n-1 The gap in the middle is 133; if n is even, then the intersection of the first reference line L1 and the third reference line L3 is located at the (n-1)th reflective grating finger GL. n-1 The gap 133 in the middle, the intersection of the second reference line L2 and the fourth reference line L4 is located at the nth reflective grating finger GL. n The gap in the middle is 133.

[0094] In Figure 7 , N=11, n=7 are taken as examples for illustration.

[0095] In the first to seventh reflective grating fingers GL1 to GL7, the first, third, fifth and seventh reflective grating fingers GL1, GL3, GL5 and GL7 all have slits 133 located on the first reference line L1; the second, fourth and sixth reflective grating fingers GL2, GL4 and GL6 all have slits 133 located on the second reference line L2; the intersection position Q1 of the first reference line L1 and the second reference line L2 is located on the side of the seventh reflective grating finger GL7 away from the interdigital electrode 12.

[0096] In the seventh to eleventh reflective grating fingers GL7 to GL 11 , the seventh, ninth and eleventh reflective grating fingers GL7, GL9 and GL 11 all have slits 133 located on the third reference line L3; the eighth and tenth reflective grating fingers GL8 and GL 10 all have slits 133 located on the fourth reference line L4; the intersection position Q2 of the third reference line L3 and the fourth reference line L4 is located on the side of the seventh reflective grating finger GL7 towards the interdigital electrode 12.

[0097] If n n , in the first to nth reflective grating fingers GL1 to GL n , a first envelope region can be formed based on the slits 133 located on the first reference line L1 and the second reference line L2; in the nth to Nth reflective grating fingers GL N , a second envelope region can be formed based on the slits 133 located on the third reference line L3 and the fourth reference line L4. The first envelope region and the second envelope region are oppositely arranged in the first direction X, which can be two conical envelope regions with opposite tips, or two trapezoidal envelope regions with opposite short bases.

[0098] If the first envelope region and the second envelope region are two conical envelope regions with opposite tips in the first direction X, not only can the effect of reducing bulk waves and improving the uniformity of reflectivity of the reflective grating 13 be achieved by a single conical envelope region, but also the bulk waves and the reflection uniformity can be optimized by the reflective grating 13 through the two conical envelope regions with opposite tips.

[0099] If the first envelope region and the second envelope region are two trapezoidal envelope regions with short bottom sides opposite in the first direction X, not only the effect of reducing bulk waves and concentrating acoustic wave energy by a single trapezoidal envelope region can be achieved, but also the effect of optimizing bulk waves and concentrating acoustic wave energy by the reflection grating 13 can be achieved more flexibly through the two trapezoidal envelope regions with short bottom sides opposite.

[0100] Optionally, in an embodiment of the present application, the first reference line L1 and the third reference line L3 are set to have the same angle with the first direction X, and the second reference line L2 and the fourth reference line L4 are set to have the same angle with the first direction X. As shown in Figure 7 , the angle between the first reference line L1 and the third reference line L3 is c, and the angle between the second reference line L2 and the fourth reference line L4 is d. This mode facilitates the process preparation of the slits 133 on each reflection grating finger GL, and reduces the patterning process of the reflection grating 13.

[0101] Further, the angle c is set to be equal to the angle d, so as to facilitate the process preparation of the slits 133 on each reflection grating finger GL, and reduce the patterning process of the reflection grating 13.

[0102] In other modes, the angle between the first reference line L1 and the third reference line L3 can be set to be different from the angle between the second reference line L2 and the fourth reference line L4, and / or the angle between the second reference line L2 and the fourth reference line L4 can be set to be equal to the angle with the first direction X, so as to more flexibly adjust the design parameters of the first envelope region and the second envelope region, and more flexibly adjust the performance of the reflection grating 13 through the first envelope region and the second envelope region opposite in the first direction X, and more flexibly optimize the performance of the surface acoustic wave resonator through the reflection grating 13.

[0103] In order to facilitate the process preparation of the reflection grating finger GL in the reflection grating 13, as shown in Figures 3-7 , all the reflection grating fingers GL in the reflection grating 13 can be set to be equidistantly distributed with the same line spacing D.

[0104] Referring to Figure 8 , Figure 8 , another top view of the reflection grating provided by the embodiment of the present application is provided, based on the above-mentioned embodiment. If n n , the reflection grating fingers GL are equidistantly distributed with a first line spacing D1 in the first reflection grating finger GL1 to the n-th reflection grating finger GL n , the reflection grating fingers GL are equidistantly distributed with a second line spacing D2 in the n-th reflection grating finger GL N to the N-th reflection grating finger GL , and the first line spacing D1 is different from the second line spacing D2. In this mode, the bulk waves and the reflection performance can be better optimized through the reflection grating 13.

[0105] In the embodiment of the present application, as shown inFigure 8 As shown, D1>D2 is set, and in other modes, D1<D2 can also be set. Among them, the smaller one of D1 and D2 is not less than the line spacing D between the reflection grid fingers GL.

[0106] In Figure 8 As shown, n=3 and N=9 are taken as examples for illustration. It is easy to know that in the embodiments of the present application, the values of n and N can be set according to requirements, and are not limited to the values provided in the embodiments of the present application.

[0107] Optionally, D1>D2 can be set. At this time, while ensuring that the reflection grid 13 has good reflection performance, the body wave can also be better reduced through the reflection grid 13.

[0108] If D1>D2, further, the line widths of the first reflection grid finger GL1 to the n-th reflection grid finger GL n all have a first line width, the n+1-th reflection grid finger GL n+1 to the N-th reflection grid finger GL N all have a second line width, and the second line width is smaller than the first line width, so as to improve the reflection performance of the reflection grid 13. In other modes, each reflection grid finger GL in the same reflection grid 13 can also have the same line width.

[0109] In the embodiments of the present application, as shown in Figures 2-8 any mode, the reflection grid 13 can be set to have a relatively arranged first bus bar 131 and a second bus bar 132; in the same reflection grid 13, each reflection grid finger GL is provided with a gap 133, and the gap 133 divides the reflection grid finger GL into a relatively first reflection grid finger segment and a second reflection grid finger segment; the first reflection grid finger segment is located between the gap 133 and the first bus bar 131, and is integrally connected with the first bus bar 131; the second reflection grid finger segment is located between the gap and the second bus bar 132, and is integrally connected with the second bus bar 132.

[0110] If one gap 133 is arranged on each reflection grid finger GL, such as n=N, an envelope area can be formed based on the first reference line L1 and the second reference line L2, so as to reduce the body wave of the surface acoustic wave resonator; if n<N, an envelope area can be formed based on the first reference line L1 and the second reference line L2, and another envelope area can be formed based on the third reference line L3 and the fourth reference line L4, so as to reduce the body wave of the surface acoustic wave resonator through the two envelope areas opposite in the first direction X.

[0111] In one embodiment of the embodiments of the present application, in the same reflection grid 13, in the direction away from the interdigital electrode 12, the reflection grid fingers are sequentially the first reflection grid finger GL1 to the N-th reflection grid finger GL Nthe first reflective grid finger GL1 to the N-1th reflective grid finger GL N-1 In the above embodiment, each of the reflective grid fingers GL has two slits 133, and the reflective grid finger segment between the two slits 133 is the floating electrode GL'. In the same reflective grid 13, the length of the floating electrode GL' decreases in sequence in the direction away from the interdigital electrode 12.

[0112] Reference Figure 9 , Figure 9 In another embodiment provided by the present application, a top view of a reflective grid is shown based on the above embodiment. In this embodiment, N=11 is taken as an example for illustration. In the same reflective grid 13, the first reflective grid finger GL1 to the Nth reflective grid finger GL N-1 In the above embodiment, each of the reflective grid fingers GL has two slits 133, and the length of the floating electrode GL' decreases in sequence in the direction away from the interdigital electrode 12. Since the intersection position Q1 is located on the Nth reflective grid finger GL N , the Nth reflective grid finger GL N has one slit 133.

[0113] Reference Figure 10 , Figure 10 In another embodiment provided by the present application, a top view of a reflective grid is shown based on the above embodiment. In this embodiment, N=11 is taken as an example for illustration. In the same reflective grid 13, the first reflective grid finger GL1 to the Nth reflective grid finger GL N In the above embodiment, each of the reflective grid fingers GL has two slits 133, and the length of the floating electrode GL' decreases in sequence in the direction away from the interdigital electrode 12. Since the intersection position Q1 is located on the Nth reflective grid finger GL N away from the interdigital electrode 12, the Nth reflective grid finger GL N has two slits 133.

[0114] Reference Figure 11 , Figure 11 In another embodiment provided by the present application, a top view of a reflective grid is shown based on the above embodiment. In this embodiment, N=11 is taken as an example for illustration. In the same reflective grid 13, the first reflective grid finger GL1 to the Nth reflective grid finger GL N In the above embodiment, each of the reflective grid fingers GL has two slits 133, and the length of the floating electrode GL' decreases in sequence in the direction away from the interdigital electrode 12. Since the intersection position Q1 is located on the Nth reflective grid finger GL

[0115] If the length of the floating electrode GL' decreases in turn in the same reflection grating 13 in the direction away from the interdigital electrode 12, or the length of the floating electrode GL' decreases in turn and then increases in turn, the body wave and the reflection performance can be better improved by the regular layout of the floating electrode GL', and the reflection performance can be more flexibly optimized and the body wave can be reduced by the reflection grating 13.

[0116] In the embodiment of the present application, the pattern structures of the two reflection gratings 13 on both sides of the interdigital electrode 12 can be the same and symmetrically arranged. In other modes, the pattern structures of the two reflection gratings 13 can also be different.

[0117] As described above, in the surface acoustic wave resonator provided by the embodiment of the present application, the body wave can be reduced by arranging the regularly distributed gaps 133 in the reflection grating 13. By regularly arranging the gaps 133 in the reflection grating 13 and weighting the gaps 133, the body wave can be weakened, the passband performance of the surface acoustic wave resonator is not affected, and the insertion loss is reduced. Specifically, by adjusting the design parameters of the gaps 133 in the reflection grating 13 (including the layout position of the gaps 133 in the reflection grating finger GL), the distribution of different frequency bands in the surface acoustic wave resonator can be changed, a smaller weight can be allocated to high frequency, and a larger weight can be allocated to low frequency, so as to realize smooth processing of the acoustic wave signal by the gap 133 and reduce the body wave.

[0118] As described above, the inclination degree of the reference line can be controlled by controlling the included angle between the reference line where the gap 133 is located and the first direction X or the second direction Y, and then the ability of the reflection grating 13 to reduce the body wave can be adjusted. Generally, the greater the inclination degree of the reference line relative to the second direction Y, the greater the weakening degree of the reflection grating 13 to the body wave, and the reference line is not perpendicular to the second direction Y. The greater the inclination degree of the first reference line L1 and the second reference line L2 relative to the second direction Y, the greater the weakening degree of the reflection grating 13 to the body wave.

[0119] In the embodiment of the present application, the weakening degree of the reflection grating 13 to the body wave is positively correlated with the inclination degree of the reference line relative to the second direction Y. The inclination degree of the reference line depends on the layout position of each gap 133 on the path.

[0120] It should be noted that in the top view provided by the embodiment of the present application, the number of strip-shaped electrodes in the interdigital electrode 12 and the number of reflection grating fingers GL in the reflection grating 13 are only simple illustrations, and do not represent the actual number of strip-shaped electrodes and reflection grating fingers GL. The actual number of strip-shaped electrodes and reflection grating fingers GL can be set based on the use requirements of the surface acoustic wave resonator.

[0121] The performance of the surface acoustic wave resonator provided by the embodiment of the present application will be further described below in combination with the comparison experimental data.

[0122] Reference is made to Figure 12 , Figure 12 The admittance curve of the surface acoustic wave resonator provided by the embodiment of the application is shown in FIG. 2, in which the horizontal axis represents frequency in GHz, and the vertical axis represents the amplitude of frequency response in dB. Figure 12 In FIG. 2, S1 represents the admittance curve of a conventional surface acoustic wave resonator, and S2 represents the admittance curve of a surface acoustic wave resonator with the reflective grating 13 shown in FIG. 1. Figure 3 The admittance curves of the two surface acoustic wave resonators are compared, and it can be found that the admittance curve of the surface acoustic wave resonator provided by the embodiment of the application is more gentle in the region indicated by the dotted ellipse, the bulk wave amplitude is lower, the influence on the passband is smaller, and the insertion loss is smaller. Figure 3 In FIG. 2, S1 represents the admittance curve of a conventional surface acoustic wave resonator, and S2 represents the admittance curve of a surface acoustic wave resonator with the reflective grating 13 shown in FIG. 1.

[0123] Based on the comparison of the admittance curves of the two surface acoustic wave resonators, it can be found that the admittance curve of the surface acoustic wave resonator provided by the embodiment of the application is more gentle in the region indicated by the dotted ellipse, the bulk wave amplitude is lower, the influence on the passband is smaller, and the insertion loss is smaller. Figure 12 In FIG. 2, S1 represents the admittance curve of a conventional surface acoustic wave resonator, and S2 represents the admittance curve of a surface acoustic wave resonator with the reflective grating 13 shown in FIG. 1. In FIG. 2, S1 represents the admittance curve of a conventional surface acoustic wave resonator, and S2 represents the admittance curve of a surface acoustic wave resonator with the reflective grating 13 shown in FIG. 1.

[0124] The admittance curves of the two surface acoustic wave resonators are compared, and it can be found that the admittance curve of the surface acoustic wave resonator provided by the embodiment of the application is more gentle in the region indicated by the dotted ellipse, the bulk wave amplitude is lower, the influence on the passband is smaller, and the insertion loss is smaller. Figure 13 In FIG. 2, S1 represents the admittance curve of a conventional surface acoustic wave resonator, and S2 represents the admittance curve of a surface acoustic wave resonator with the reflective grating 13 shown in FIG. 1. Figure 13 Figure 13 Based on the comparison of the admittance curves of the two surface acoustic wave resonators, it can be found that the admittance curve of the surface acoustic wave resonator provided by the embodiment of the application is more gentle in the region indicated by the dotted ellipse, the bulk wave amplitude is lower, the influence on the passband is smaller, and the insertion loss is smaller. Figure 4 In FIG. 2, S1 represents the admittance curve of a conventional surface acoustic wave resonator, and S2 represents the admittance curve of a surface acoustic wave resonator with the reflective grating 13 shown in FIG. 1. Figure 4 The admittance curves of the two surface acoustic wave resonators are compared, and it can be found that the admittance curve of the surface acoustic wave resonator provided by the embodiment of the application is more gentle in the region indicated by the dotted ellipse, the bulk wave amplitude is lower, the influence on the passband is smaller, and the insertion loss is smaller.

[0125] Based on the comparison of the admittance curves of the two surface acoustic wave resonators, it can be found that the admittance curve of the surface acoustic wave resonator provided by the embodiment of the application is more gentle in the region indicated by the dotted ellipse, the bulk wave amplitude is lower, the influence on the passband is smaller, and the insertion loss is smaller. Figure 13 In FIG. 2, S1 represents the admittance curve of a conventional surface acoustic wave resonator, and S2 represents the admittance curve of a surface acoustic wave resonator with the reflective grating 13 shown in FIG. 1. In FIG. 2, S1 represents the admittance curve of a conventional surface acoustic wave resonator, and S2 represents the admittance curve of a surface acoustic wave resonator with the reflective grating 13 shown in FIG. 1.

[0126] The comparison of Figure 3 and Figure 4 shows that the inclination of the two reference lines in the reflective grating 13 shown in FIG. 1 relative to the second direction Y is greater. Figure 4 The comparison of Figure 12 and Figure 13 shows that the admittance curve corresponding to S2 in FIG. 2 is more gentle in the region indicated by the dotted ellipse, and therefore Figure 13 the ability to weaken the bulk wave is greater. Figure 12 The experimental comparison results of Figure 13 show that the inclination of the reference line is positively correlated with the ability to weaken the bulk wave.

[0127] Reference is made to Figure 14 , Figure 14The admittance curve of another surface acoustic wave resonator provided in this application embodiment is shown. The horizontal axis is the frequency in GHz, and the vertical axis is the amplitude of the frequency response in dB. Figure 14 In the diagram, S1 represents the admittance curve of a conventional surface acoustic wave resonator; S2 and S3 represent the admittance curves of resonators with... Figure 11 The admittance curves of the surface acoustic wave resonator of the reflector grating 13 shown are different in that the inclination of the reference line in the reflector grating 13 is different. Compared with the S2 correspondence, the inclination of the reference line relative to the second direction Y is greater in the S3 correspondence. Figure 14 The only difference between the three surface acoustic wave resonators is that the S2 / S3 corresponding surface acoustic wave resonator has a feature set in the reflection grating 13. Figure 11 The gap shown is 133.

[0128] based on Figure 14 It can be seen that, compared to S1, S2 and S3 are more gentle in the dashed elliptical region, with lower volume wave amplitude, less impact on the passband, and smaller insertion loss. The fact that S3 is more gentle in the dashed elliptical region, with lower volume wave amplitude, less impact on the passband, and smaller insertion loss compared to S2 indicates that the inclination of the reference line is positively correlated with its ability to weaken volume waves.

[0129] refer to Figure 15 , Figure 15 The image shows the passband curve of a surface acoustic wave resonator provided in an embodiment of this application. The horizontal axis represents frequency in GHz, and the vertical axis represents signal power in dB. Figure 15 and Figure 1 The corresponding surface acoustic wave resonators all have 16 reflective gratings GL in their reflective gratings 13, and... Figure 1 The only difference between the corresponding surface acoustic wave resonators is that Figure 15 The corresponding surface acoustic wave resonator has an added feature in the reflector grating 13, such as... Figure 3 The gap shown is 133.

[0130] like Figure 15 As shown, comparison Figure 1 As shown in the passband curves, the surface acoustic wave resonator designed based on the embodiments of this application exhibits high performance in the same region ( Figure 1 The collapse of the elliptical region shown in the figure is significantly reduced.

[0131] pass Figure 1 and Figure 15 As can be seen from the comparison of the passband curves, the surface acoustic wave resonator designed based on the embodiments of this application can effectively reduce bulk waves and solve the insertion loss problem.

[0132] Furthermore, experimental data shows that the surface acoustic wave resonator provided in this application embodiment can also reduce the k-value of the resonator. 2 Parameters can be used when a lower k is required. 2The application scenario of the parameter. The surface acoustic wave resonator provided in the embodiment of the application reduces the bulk wave without obvious change in the Q value.

[0133] Optionally, on the basis of any one of the above embodiments, the interdigital electrode 12 of the surface acoustic wave resonator can further include a dummy finger electrode, and the dummy finger electrode is used to achieve better resonator performance. Specifically, a plurality of first dummy finger electrodes corresponding to the second finger strips 122 one by one can be arranged on the third bus bar 123, and the first dummy finger electrodes and the second finger strips 122 have a gap therebetween to prevent short circuit; a plurality of second dummy finger electrodes corresponding to the first finger strips 121 one by one can be arranged on the fourth bus bar 124, and the second dummy finger electrodes and the first finger strips 121 have a gap therebetween to prevent short circuit. In this way, the interdigital electrode 12 needs to occupy a larger layout space.

[0134] Optionally, on the basis of any one of the above embodiments, a temperature compensation layer can be arranged on the surface of the interdigital electrode 12 and the reflector 13 to form a temperature compensation type surface acoustic wave resonator (TC-SAW). Optionally, the temperature compensation layer can be a SiO2 layer. The temperature compensation layer is used to overcome the temperature drift problem.

[0135] Optionally, on the basis of any one of the above embodiments, the surface acoustic wave resonator can be a thin film surface acoustic wave resonator (TF-SAW), and in this case, the piezoelectric substrate 11 is a substrate with a piezoelectric film, and the reflector 13 and the interdigital electrode 12 are arranged on the surface of the piezoelectric film away from the substrate.

[0136] In order to better reduce the bulk wave through the reflector 13 to reduce the insertion loss, the embodiment of the application can further include at least one of the following modes: a dummy finger is arranged in the reflector 13; a plug structure is arranged on the reflector finger GL.

[0137] Another embodiment of the application further provides a filter, and the filter includes the surface acoustic wave resonator provided in any one of the above embodiments.

[0138] The filter provided in the embodiment of the application adopts the surface acoustic wave resonator provided in the above embodiments, can reduce the bulk wave through the reflector 13, thereby reducing the insertion loss of the surface acoustic wave resonator, can improve the performance of the surface acoustic wave resonator, and further can improve the performance of the filter.

[0139] Another embodiment of the application further provides an electronic device, and the electronic device includes the filter provided in the above embodiments.

[0140] Optionally, the electronic device can be a mobile phone, a base station, a radar device, a digital television, a satellite communication device, a positioning device, a medical device for acoustic imaging, or the like. The embodiment of the application is not limited to the implementation mode and application field of the electronic device.

[0141] The electronic device provided by the embodiment of the present application adopts the filter provided by the above embodiment, can effectively reduce the insertion loss of the surface acoustic wave resonator through the reflection grid 13, and will not affect the passband performance of the resonator, thereby improving the performance of the electronic device.

[0142] In the description of the present application, each embodiment is described in a progressive, or parallel, or a combination of progressive and parallel manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between each embodiment can be referred to each other. The embodiments provided by the embodiments of the present application can be combined with each other without contradiction.

[0143] It should be noted that in the description of the present application, it should be understood that the description of the drawings and the embodiments is illustrative rather than limiting. The same reference numerals in the embodiments throughout the specification indicate the same structure. In addition, for the purpose of understanding and ease of description, the thickness of some layers, films, panels, regions and the like in the drawings may be exaggerated. At the same time, it can be understood that when an element such as a layer, film, region or substrate is referred to as "on" another element, the element can be directly on the other element or there can be an intermediate element. In addition, "on" refers to positioning an element on another element or below another element, but not essentially refers to positioning on the upper side of another element according to the direction of gravity.

[0144] The terms "upper", "lower", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there can be a component disposed therebetween.

[0145] It should also be noted that in this paper, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such article or device. Without more limitation, the element defined by the sentence "including a…" does not exclude the presence of other identical elements in the article or device including the above-mentioned element.

[0146] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A surface acoustic wave resonator, characterized by, The application relates to a piezoelectric substrate for sound-electric conversion; an interdigital electrode arranged on one side surface of the piezoelectric substrate for sound-electric conversion by applying voltage to excite the piezoelectric substrate; the interdigital electrode comprises first fingers and second fingers arranged alternately in a first direction; the first fingers and the second fingers both extend along a second direction, and the first direction and the second direction intersect on a plane parallel to the plane where the piezoelectric substrate is located; two reflective gratings arranged on the same side surface of the piezoelectric substrate as the interdigital electrode, and the interdigital electrode is located between the two reflective gratings in the first direction; wherein the reflective gratings comprise a plurality of reflective grating fingers arranged sequentially along the first direction; in the direction away from the interdigital electrode, the plurality of reflective grating fingers are sequentially the first reflective grating finger to the Nth reflective grating finger, and N is a positive integer greater than 1; for the same reflective grating, in the first reflective grating finger to the nth reflective grating finger, the (2i-1)th reflective grating finger has a gap on a first reference line, and the (2i)th reflective grating finger has a gap on a second reference line, the first reference line intersects the second reference line, and the intersection position is located on the side of the first reflective grating finger away from the interdigital electrode; wherein n is a positive integer not greater than N; i is a positive integer, and 2i is not greater than n; n < N; the intersection position of the first reference line and the second reference line is located on the side of the nth reflective grating finger away from the interdigital electrode; for the same reflective grating, in the nth reflective grating finger to the Nth reflective grating finger, the (2j-1)th reflective grating finger has a gap on a third reference line, and the (2j)th reflective grating finger has a gap on a fourth reference line, the third reference line intersects the fourth reference line, and the intersection position is located on the side of the nth reflective grating finger towards the interdigital electrode; wherein j is a positive integer; 2j-1 is not less than n, and 2j is not greater than N; in the first reflective grating finger to the nth reflective grating finger, the reflective grating fingers are equally distributed with a first line spacing D1; in the nth reflective grating finger to the Nth reflective grating finger, the reflective grating fingers are equally distributed with a second line spacing D2; D1 > D2. The first reference line and the second reference line are equal in angle with the first direction. The first reference line and the third reference line are equal in angle with the first direction. The second reference line and the fourth reference line are equal in angle with the first direction. The reflective gratings have oppositely arranged first bus bars and second bus bars; In the same reflective grating, the reflective grating fingers are all provided with one gap, and the gap divides the reflective grating finger into opposite first reflective grating finger segments and second reflective grating finger segments; the first reflective grating finger segment is located between the gap and the first bus bar and is integrally connected with the first bus bar; the second reflective grating finger segment is located between the gap and the second bus bar and is integrally connected with the second bus bar. ​ ​ 2. The surface acoustic wave resonator according to claim 1, characterized by, ​ 3. The surface acoustic wave resonator according to claim 1, wherein ​ ​ 4. The surface acoustic wave resonator according to any one of claims 1 to 3, characterized by ​ ​ 5. The surface acoustic wave resonator according to any one of claims 1 to 3, characterized by In the same reflective grating, along a direction away from the interdigital electrode, the plurality of reflective grating fingers are sequentially a first reflective grating finger to an Nth reflective grating finger, N is a positive integer greater than 1. In the first reflective grating finger to the (N-1)th reflective grating finger, the reflective grating finger has two gaps, and a reflective grating finger segment of the reflective grating finger between the two gaps is a floating electrode; wherein, in the same reflective grating, along a direction away from the interdigital electrode, lengths of the floating electrodes sequentially decrease, or lengths of the floating electrodes sequentially decrease and then sequentially increase.

6. A filter characterized by, A surface acoustic wave resonator comprising any one of claims 1-5.

7. An electronic device, comprising: A filter comprising the surface acoustic wave resonator of claim 6.

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