Resonator, filter and radio frequency front-end module

Abstract

The utility model is applicable to the field of radio frequency filtering, and discloses a resonator, a filter and a radio frequency front-end module, the resonator comprises a piezoelectric substrate and an interdigital transducer, and the interdigital transducer comprises a first bus bar and a second bus bar which are oppositely arranged along a first direction; the at least one first electrode finger, the at least one second electrode finger and the at least one suspension electrode are located between the first bus bar and the second bus bar, the first electrode fingers, the suspension electrodes and the second electrode fingers are arranged at intervals in the second direction, and the first electrode fingers and the second electrode fingers are arranged in a staggered mode in the second direction; in the second direction, the suspension electrodes and the main body parts of the first electrode fingers are alternately arranged and mutually overlapped to form a first resonance unit, and the suspension electrodes and the main body parts of the second electrode fingers are alternately arranged and mutually overlapped to form a second resonance unit. According to the resonator, the layout area can be reduced, and the performance of the resonator can be improved.

Description

Technical Field

[0001] The present application relates to the field of radio frequency filtering technology, and in particular to a resonator, a filter and a radio frequency front-end module. Background Art

[0002] A surface acoustic wave (SAW) resonator is a device that can convert an electrical signal into an acoustic signal or convert an acoustic signal into an electrical signal. A surface acoustic wave resonator generally includes a piezoelectric substrate and an interdigital transducer formed on the piezoelectric substrate, and the interdigital transducer is used to convert an electrical signal into an acoustic signal or convert an acoustic signal into an electrical signal.

[0003] It is understood that surface acoustic wave devices are widely used in the design of multiplexers or duplexers due to their small size and low insertion loss. However, as the Q value of the resonator increases, the resonator's heterodyne mode will become more obvious, which will reduce the performance of the resonator. Therefore, it is currently an urgent problem to achieve miniaturization of the resonator while improving the performance of the resonator. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a resonator, a filter and a radio frequency front-end module, which are intended to improve the performance of the resonator while achieving the miniaturization of the resonator.

[0005] In order to solve the above technical problems, an embodiment of the present application provides a resonator, including:

[0006] Piezoelectric substrate;

[0007] an interdigital transducer formed on the piezoelectric substrate;

[0008] The IDT comprises a first bus bar and a second bus bar arranged opposite to each other along a first direction, and at least one first electrode finger, at least one second electrode finger and at least one suspension electrode located between the first bus bar and the second bus bar, wherein the first electrode finger, the suspension electrode and the second electrode finger are arranged at intervals along a second direction, and the first electrode finger and the second electrode finger are staggered in the second direction, and the first direction and the second direction are orthogonal;

[0009] The first electrode finger and the second electrode finger each include a connecting portion, a main portion, and an intermediate portion connected between the connecting portion and the main portion, the connecting portion of the first electrode finger is connected to the first bus bar, and the connecting portion of the second electrode finger is connected to the second bus bar;

[0010] In the first direction, the connecting portion and the main body are respectively located on two sides of the middle portion;

[0011] In the second direction, the floating electrodes and the main body of the first electrode fingers are alternately arranged and overlapped to form a first resonance unit, and the floating electrodes and the main body of the second electrode fingers are alternately arranged and overlapped to form a second resonance unit.

[0012] In some embodiments, the suspension electrode includes a first portion, a second portion, and a third portion, and in the first direction, the first portion and the second portion are respectively located on both sides of the third portion;

[0013] The first portion and the main body of the first electrode finger are alternately arranged along the second direction and overlap with each other to form the first resonance unit, and the second portion and the main body of the second electrode finger are alternately arranged along the second direction and overlap with each other to form the second resonance unit.

[0014] In some embodiments, the connecting portion of the first electrode finger, the first portion, and the main portion of the second electrode finger are sequentially arranged in intervals along the first direction;

[0015] and / or,

[0016] The connecting portion of the second electrode finger, the second portion, and the main body of the first electrode finger are sequentially arranged at intervals along the first direction.

[0017] In some embodiments, the third portion is spaced apart from a middle portion of the first electrode finger and a middle portion of the second electrode finger along the first direction.

[0018] In some embodiments, in the second direction, two adjacent floating electrodes are connected via the third portion.

[0019] In some embodiments, the width of the third portion along the first direction is greater than the width of the first portion along the second direction; and / or,

[0020] A width of the third portion along the first direction is greater than a width of the second portion along the second direction.

[0021] In some embodiments, the third portion includes a first suspended portion and a second suspended portion, and the first suspended portion and the second suspended portion are connected to each other and enclose a first opening.

[0022] In some embodiments, the first opening is rectangular in shape.

[0023] In some embodiments, the connecting portion and the middle portion are connected at an angle, and the middle portion and the main body portion are connected at an angle;

[0024] The first bus bar, the connecting portion of the first electrode finger and the middle portion of the first electrode finger form a second opening, and the second opening is oriented in the direction from the connecting portion to the middle portion of the same first electrode finger; and / or the second bus bar, the connecting portion of the second electrode finger and the middle portion of the second electrode finger form a third opening, and the third opening is oriented in the direction from the connecting portion to the middle portion of the same second electrode finger.

[0025] In some embodiments, the suspension electrode includes a suspension electrode unit, and the suspension electrode unit is alternately arranged with the first electrode fingers and the second electrode fingers along the second direction and overlaps with each other.

[0026] In some embodiments, the suspension electrode includes at least two suspension electrode units, and the at least two suspension electrode units are arranged along the first direction;

[0027] The floating electrode units close to the first bus bar are alternately arranged with the first electrode fingers along the second direction and overlap with each other;

[0028] The floating electrode units close to the second bus bar are alternately arranged with the second electrode fingers along the second direction and overlap with each other;

[0029] Two adjacent floating electrode units are alternately arranged along the second direction and overlap each other to form a third resonance unit.

[0030] In some embodiments, the piezoelectric substrate includes a substrate and a piezoelectric layer, the piezoelectric layer is disposed on the substrate, and the interdigital transducer is formed on the piezoelectric layer;

[0031] The temperature coefficient of the substrate is smaller than the temperature coefficient of the piezoelectric layer, and / or the thickness of the substrate is larger than the thickness of the piezoelectric layer.

[0032] In some embodiments, the piezoelectric substrate further comprises an intermediate layer, wherein the intermediate layer is disposed between the piezoelectric layer and the substrate;

[0033] The intermediate layer includes at least one low acoustic velocity layer or low acoustic impedance layer, and the substrate is a high acoustic velocity layer or a high acoustic impedance layer.

[0034] In some embodiments, the resonator further includes a temperature compensation layer, which is disposed on the piezoelectric substrate and covers at least the first resonance unit and the second resonance unit.

[0035] In some embodiments, the resonance frequencies of the first resonance unit and the second resonance unit are the same.

[0036] An embodiment of the present application also provides a filter, which includes the above-mentioned resonator.

[0037] An embodiment of the present application also provides a radio frequency front-end module, which includes the above-mentioned resonator.

[0038] The resonator provided by the present application has the following beneficial effects:

[0039] In the resonator of this embodiment, the first electrode finger and the second electrode finger are staggered in the second direction, and the suspension electrode and the main body of the first electrode finger are alternately arranged and overlapped along the second direction to form a first resonance unit, and the suspension electrode and the main body of the second electrode finger are alternately arranged and overlapped along the second direction to form a second resonance unit, so that the first resonance unit and the second resonance unit are arranged at intervals in the first direction, and the first resonance unit and the second resonance unit are cascaded not through the bus bar but through the suspension electrode, which can reduce the layout area and realize the miniaturization of the resonator.

[0040] At the same time, in the first electrode finger and the second electrode finger, the connecting portion and the main body are respectively located on both sides of the middle portion along the first direction, so that in the area between the first bus bar and the first resonance unit (the first gap area), the first electrode finger has a bent shape, and in the area between the second bus bar and the second resonance unit (the second gap area), the second electrode finger has a bent shape. In this way, the bent shape of the first electrode finger and the bent shape of the second electrode finger can respectively suppress the stray modes generated in the first gap area and the second gap area, which can improve the suppression effect of the stray modes, avoid the stray mode resonance phenomenon when the resonators are cascaded, and thus improve the performance of the resonator. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0042] Figure 1 is a schematic diagram of the structure of a resonator provided in an embodiment of the present application;

[0043] Figure 2 This is a schematic diagram of the first structure of the interdigital transducer in the resonator provided in the embodiment of the present application;

[0044] Figure 3 is a second structural schematic diagram of the interdigital transducer in the resonator provided in an embodiment of the present application;

[0045] Figure 4 yes Figure 3 A local enlarged schematic diagram of point i in the middle;

[0046] Figure 5 This is a schematic diagram of a third structure of an interdigital transducer in a resonator provided in an embodiment of the present application;

[0047] Figure 6 This is a schematic diagram of a fourth structure of an interdigital transducer in a resonator provided in an embodiment of the present application;

[0048] Figure 7 yes Figure 6 Schematic diagram of some structures;

[0049] Figure 8 is a schematic structural diagram of a comparative example of a resonator provided in an embodiment of the present application;

[0050] Fig. 9 is a schematic diagram of an admittance curve of Example 1 of the resonator provided in the embodiments of the present application;

[0051] Fig.10 It is a schematic diagram of the admittance curve of the comparative example in the resonator provided in the embodiment of the present application.

[0052] Description of Figure Numbers:

[0053] 1. Resonator;

[0054] 10. piezoelectric substrate; 20. interdigital transducer; 21. first bus bar; 22. second bus bar; 23. first electrode finger; 231. second opening; 24. second electrode finger; 241. third opening; 25. suspension electrode; 251. first portion; 252. second portion; 253. third portion; 2531. main body; 2532. extension portion; 2533. first suspension portion; 2534. second suspension portion; 2535. first opening; 254. suspension electrode unit; 254a. first suspension electrode unit; 254b. second suspension electrode unit; 201. connection portion; 202. main body; 203. middle portion; 204. first resonance unit; 205. second resonance unit; 206. third resonance unit; H. gap region; G1. first gap region; G2. second gap region; C1. cross transduction region; C2. edge region. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0057] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or may be indirectly connected to the other element through an intermediate element.

[0058] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0059] In the related art, the power handling capacity of the surface acoustic wave filter is increased by using the same resonator cascade and sharing the same bus bar, but this will lead to an increase in the layout area, and as the Q value of the resonator increases, the resonator's heterodyne will become more obvious, which will reduce the performance of the resonator. For filters using resonators with higher Q values ​​(such as temperature-compensated surface acoustic wave resonators, piezoelectric film-type surface acoustic wave resonators with multi-layer substrate structures), the same resonators are cascaded and share the same bus bar, and the frequency amplitude of the heterodyne modes of each resonator is the same, which will cause the heterodyne mode to resonate, thereby adversely affecting the performance of the filter.

[0060] In view of this, refer to Figure 1 and Figure 2 The embodiment of the present application provides a resonator 1, which is provided with a floating electrode 25 between a first bus bar 21 and a second bus bar 22, and the floating electrode 25 forms a first resonance unit 204 and a second resonance unit 205 with a first electrode finger 23 and a second electrode finger 24 in the resonator 1, respectively, and the first resonance unit 204 and the second resonance unit 205 are arranged at intervals in the arrangement direction of the first bus bar 21 and the second bus bar 22, which can not only reduce the layout area and realize the miniaturization of the resonator, but also suppress the stray mode in the gap area, avoid the resonance phenomenon of the stray mode when the resonator is cascaded, improve the performance of the resonator, and improve the performance of the filter.

[0061] The following is combined with Figures 1 to 7 , some embodiments of the present application are described in detail. In the absence of conflict, the following embodiments and features of the embodiments can be combined with each other.

[0062] It should be noted that in the accompanying drawings, Figures 1 to 7 It is only exemplary, for the convenience of illustration, Figure 1 The structure of the resonator 1 is shown as an example, and it is obvious that this is not intended to limit the specific structure of the resonator 1; Figure 2 , Figure 3 , Figure 5 and Figure 6 One structure of the interdigital transducer 20 is exemplarily shown, wherein: Figure 3 and Figure 5 The structures of the interdigital transducers shown can be regarded as Figure 2 The deformations based on the structure of the IDT are shown. Obviously, these are not limitations on the specific structure of the IDT 20 on the resonator 1. The drawings can illustrate them together if there is no conflict.

[0063] Reference Figure 1 , Figure 2 and Figure 3 The resonator 1 of the embodiment of the present application includes a piezoelectric substrate 10 and an IDT 20 formed on the piezoelectric substrate 10, the IDT 20 includes a first bus bar 21 and a second bus bar 22 arranged opposite to each other along a first direction, and at least one first electrode finger 23, at least one second electrode finger 24 and at least one suspension electrode 25 located between the first bus bar 21 and the second bus bar 22, the first electrode finger 23, the suspension electrode 25 and the second electrode finger 24 are arranged at intervals along a second direction, and the first electrode finger 23 and the second electrode finger 24 are staggered in the second direction, and the first direction and the second direction are orthogonal;

[0064] The first electrode finger 23 and the second electrode finger 24 each include a connecting portion 201, a main portion 202, and a middle portion 203 connected between the connecting portion 201 and the main portion 202. The connecting portion 201 of the first electrode finger 23 is connected to the first bus bar 21, and the connecting portion 201 of the second electrode finger 24 is connected to the second bus bar 22. In the first direction, the connecting portion 201 and the main portion 202 are respectively located on both sides of the middle portion 203. In the second direction, the floating electrodes 25 and the main portion 202 of the first electrode finger 23 are alternately arranged and overlapped with each other to form a first resonance unit 204, and the floating electrodes 25 and the main portion 202 of the second electrode finger 24 are alternately arranged and overlapped with each other to form a second resonance unit 205.

[0065] In this embodiment, the resonator includes a piezoelectric substrate 10 and an IDT 20, wherein the IDT 20 is formed on the piezoelectric substrate 10 and is used to realize acoustic-electric transduction. The IDT 20 includes a first bus bar 21 and a second bus bar 22 arranged opposite to each other along a first direction, and the first direction can be understood as the arrangement direction of the first bus bar 21 and the second bus bar 22.

[0066] Combination Figure 2 The IDT 20 further includes a plurality of first electrode fingers 23, a plurality of second electrode fingers 24, and a plurality of suspension electrodes 25. Different parts of the same suspension electrode 25 overlap with the first electrode fingers 23 and the second electrode fingers 24 in the second direction, and the suspension electrodes 25 are not connected to the first bus bar 21, the second bus bar 22, the first electrode fingers 23, and the second electrode fingers 24. In the second direction, the suspension electrodes 25 and the first electrode fingers 23 of the first resonance unit 204 are alternately arranged, and the suspension electrodes 25 and the second electrode fingers 24 of the second resonance unit 205 are alternately arranged.

[0067] In this embodiment, the first electrode finger 23 and the second electrode finger 24 are staggered in the second direction. It can be understood that the first electrode finger 23 and the second electrode finger 24 are arranged at intervals along the first direction and staggered in the second direction so that the first electrode finger 23 and the second electrode finger 24 do not overlap each other along the second direction. On this basis, in this embodiment, the first electrode finger 23 and the second electrode finger 24 both include a connecting portion 201, a main portion 202, and an intermediate portion 203 connected between the connecting portion 201 and the main portion 202. The connecting portion 201 of the first electrode finger 23 is connected to the first bus bar 21, and the connecting portion 201 of the second electrode finger 24 is connected to the second bus bar 22. In addition, the same suspension electrode 25 overlaps with the first electrode finger 23 and the second electrode finger 24 in the second direction, and the suspension electrode 25 and the main portion 202 of the first electrode finger 23 are alternately arranged along the second direction to form a first resonance unit 204. The suspension electrode 25 is connected to the first bus bar 21, and the second bus bar 22 is connected to the second bus bar 22. 25 and the main body 202 of the second electrode finger 24 are alternately arranged along the second direction to form a second resonance unit 205. In this way, the first resonance unit 204 and the second resonance unit 205 are arranged at intervals in the first direction. Moreover, the first resonance unit 204 and the second resonance unit 205 are not cascaded through the bus bar, but are cascaded through the common suspension electrode 25, which can effectively ensure that the electrical performance of the resonator 1 is not affected, and optimize the internal finger arrangement mode, reduce the layout area, and realize the miniaturization of the resonator. It can also suppress the stray mode in the gap area, avoid the resonance phenomenon of the stray mode when the resonator is cascaded, and improve the performance of the resonator.

[0068] At the same time, in the present embodiment, in the first electrode finger 23 and the second electrode finger 24, the connecting portion 201 and the main body portion 202 are respectively located on both sides of the middle portion 203 along the first direction, so that the first electrode finger 23 has a bent shape in the area between the first bus bar 21 and the first resonance unit 204, and the second electrode finger 24 has a bent shape in the area between the second bus bar 22 and the second resonance unit 205. It should be understood that the area between the first bus bar 21 and the first resonance unit 204 is the first gap area G1, and the area between the second bus bar 22 and the second resonance unit 205 is the second gap area G2. In this way, the bent shape of the first electrode finger 23 and the bent shape of the second electrode finger 24 can respectively suppress the stray modes generated in the first gap area G1 and the second gap area G2, further improving the suppression effect of the stray modes, thereby improving the performance of the resonator 1 and the filter having the resonator 1.

[0069] It should be noted that, in this embodiment, for ease of understanding, the first direction is defined as the up-down direction parallel to the surface of the piezoelectric substrate 10, and the second direction is defined as the left-right direction parallel to the surface of the piezoelectric substrate 10. Figure 2 For the suspension electrode 25 , the first bus bar 21 is located above the suspension electrode 25 , the second bus bar 22 is located below the suspension electrode 25 , the main body 202 of the first electrode finger 23 is located on the right side of the same suspension electrode 25 , and the main body 202 of the second electrode finger 24 is located on the left side of the same suspension electrode 25 .

[0070] Combination Figure 2 and Figure 3 In some embodiments, the floating electrode 25 includes a first portion 251 and a second portion 252, the first portion 251 and the main portion 202 of the first electrode finger 23 have an overlapping region in the second direction, the second portion 252 and the main portion 202 of the second electrode finger 24 have an overlapping region in the second direction, and the two overlapping regions are arranged at intervals in the first direction; moreover, the first portion 251 is not connected to the first bus bar 21 and the first electrode finger 23, and the second portion 252 is not connected to the second bus bar 22 and the second electrode finger 24, so that the first portion 251 and the main portion 202 of the first electrode finger 23 are alternately arranged to form a first resonance unit 204, and the second portion 252 and the main portion 202 of the second electrode finger 24 are alternately arranged to form a second resonance unit 205, which is arranged at an interval up and down. The arrangement of the floating electrode 25 can make the two resonators share the bent finger portion, suppress the stray mode generated in the gap region H, and avoid the resonance phenomenon of the stray mode of the cascaded resonator.

[0071] The gap region H can be understood as the region between two adjacent resonators when at least two resonators are cascaded. More specifically, it can be understood as Figure 2 and Figure 3The area between the first resonance unit 204 and the second resonance unit 205 is shown.

[0072] like Figures 1 to 3 As shown, in some embodiments, the floating electrode 25 includes a first portion 251, a second portion 252 and a third portion 253. In the first direction, the first portion 251 and the second portion 252 are respectively located on both sides of the third portion 253; the first portion 251 and the main body 202 of the first electrode finger 23 are alternately arranged and overlapped with each other along the second direction to form a first resonance unit 204, and the second portion 252 and the main body 202 of the second electrode finger 24 are alternately arranged and overlapped with each other in the second direction to form a second resonance unit 205.

[0073] Combination Figure 3 In the suspension electrode 25 of the present embodiment, the first portion 251 and the second portion 252 are respectively located at the upper and lower sides of the third portion 253 along the first direction, so that the first resonance unit 204 is located above the third portion 253, and the second resonance unit 205 is located below the third portion 253. Furthermore, the first resonance unit 204 and the second resonance unit 205 are arranged with an upper and lower interval in the first direction. The arrangement of the suspension electrode 25 can make the two resonators share the bending finger part, suppress the stray mode generated in the gap area H, and avoid the resonance phenomenon of the stray mode of the cascaded resonators.

[0074] like Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments, the connecting portion 201 of the first electrode finger 23 , the first portion 251 , and the main body 202 of the second electrode finger 24 are sequentially arranged in intervals along the first direction.

[0075] In this embodiment, the connecting portion 201 and the first portion 251 of the first electrode finger 23 are arranged at intervals along the first direction, the first portion 251 and the main body 202 of the second electrode finger 24 are arranged at intervals along the first direction, and the connecting portion 201, the first portion 251 and the main body 202 of the first electrode finger 23 and the second electrode finger 24 all extend along the first direction. Figure 3 and Figure 4 In some embodiments, the connection portion 201 of the first electrode finger 23, the first portion 251, and the main portion 202 of the second electrode finger 24 are all located on the same straight line, and the connection portion 201 of the first electrode finger 23 and the main portion 202 of the second electrode finger 24 are respectively located above and below the first portion 251. In other embodiments, the connection portion 201 of the first electrode finger 23 and the first portion 251 are staggered along the second direction, and the first portion 251 and the main portion 202 of the second electrode finger 24 are staggered along the second direction.

[0076] like Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments, the connecting portion 201 , the second portion 252 of the second electrode finger 24 , and the main body 202 of the first electrode finger 23 are sequentially arranged in intervals along the first direction.

[0077] In this embodiment, the connecting portion 201 and the second portion 252 of the second electrode finger 24 are spaced apart along the first direction, the second portion 252 and the main body 202 of the first electrode finger 23 are spaced apart along the first direction, and the connecting portion 201, the second portion 252 and the main body 202 of the first electrode finger 23 all extend along the first direction. Figure 3 and Figure 4 In some embodiments, the connecting portion 201, the second portion 252 of the second electrode finger 24 and the main portion 202 of the first electrode finger 23 are all located on the same straight line, and the main portion 202 of the first electrode finger 23 and the connecting portion 201 of the second electrode finger 24 are respectively located above and below the second portion 252. In other embodiments, the connecting portion 201 of the second electrode finger 24 and the second portion 252 are staggered along the second direction, and the second portion 252 and the main portion 202 of the first electrode finger 23 are staggered along the second direction.

[0078] like Figures 1 to 4 As shown, in some embodiments, the third portion 253 is spaced apart from the middle portion 203 of the first electrode finger 23 and the middle portion 203 of the second electrode finger 24 along the first direction.

[0079] In this embodiment, in the first direction, the middle portion 203 of the first electrode finger 23 and the third portion 253 are arranged at intervals, the middle portion 203 of the second electrode finger 24 and the third portion 253 are arranged at intervals, and the first portion 251 and the second portion 252 are respectively located on both sides of the third portion 253 in the first direction. At the same time, the first electrode finger 23 and the second electrode finger 24 are staggered in the second direction, so that the first portion 251 and the second portion 252 are also staggered in the second direction, and the first portion 251 and the second portion 252 do not overlap, effectively ensuring that the first resonance unit 204 and the second resonance unit 205 do not overlap. It can be understood that, combined with Figure 4 The first part 251 is located above the third part 253 , the second part 252 is located below the third part 253 , and the first part 251 and the second part 252 are staggered left and right relative to the third part 253 .

[0080] like Figure 1 and Figure 3 As shown, in some embodiments, in the second direction, two adjacent suspension electrodes 25 are connected via the third portion 253 .

[0081] In this embodiment, among two adjacent suspension electrodes 25 in the second direction, the third portion 253 of one suspension electrode 25 is connected to the third portion 253 of the other suspension electrode 25 to conduct the two adjacent suspension electrodes 25, thereby effectively ensuring the integrity of the resonant cavity of the resonator 1 and ensuring that the main mode of the resonator 1 is not affected when the stray mode is suppressed.

[0082] In some embodiments, the third portion 253 includes a main body portion 2531 and an extension portion 2532 extending along the second direction, the first portion 251 is connected to one end of the main body portion 2531, the second portion 252 is connected to the other end of the main body portion 2531, and in the second direction, the main bodies 2531 of two adjacent third portions 253 are connected through the extension portion 2532 to achieve conduction between two adjacent floating electrodes 25 in the second direction.

[0083] like Figure 3 and Figure 4 As shown, in some embodiments, the width of the third portion 253 is greater than the width of the first portion 251. In this embodiment, the width of the third portion 253 is set to be greater than the width of the first portion 251, which can reduce the resistance of the third portion 253. It can be understood that the width of the third portion 253 is the size of the third portion 253 along the first direction, and the width of the first portion 251 is the size of the first portion 251 along the second direction, that is, the width of the third portion 253 is defined as w1, and the width of the first portion 251 is defined as w2, then in this embodiment, w1>w2.

[0084] like Figure 3 and Figure 4 As shown, in some embodiments, the width of the third portion 253 is greater than the width of the second portion 252. In this embodiment, the width of the third portion 253 is set to be greater than the width of the second portion 252, which can reduce the resistance of the third portion 253. It should be understood that in combination with the embodiment in which the width of the third portion 253 is greater than the width of the first portion 251, the width of the second portion 252 is the size of the second portion 252 along the second direction, and the width of the second portion 252 is defined as w3, then in this embodiment, w1>w3.

[0085] like Figure 3 and Figure 4As shown, in some embodiments, on the basis of setting the width of the third portion 253 to be greater than the width of the first portion 251, and the width of the third portion 253 to be greater than the width of the second portion 252, the width of the first bus bar 21 and the width of the second bus bar 22 can also be set to be greater than the width of the third portion 253, so that the resistance of the third portion 253 can be reduced while reducing the layout area. It should be understood that the width of the first bus bar 21 and the second bus bar 22 is the size of the first bus bar 21 and the second bus bar 22 along the first direction, and the width of the first bus bar 21 is defined as w4, the width of the second bus bar 22 is defined as w5, and w1>w2, and w1>w3, and at the same time, w1<w4, and w1<w5.

[0086] like Figure 5 As shown, in some embodiments, the third portion 253 includes a first suspended portion 2533 and a second suspended portion 2534 , and the first suspended portion 2533 and the second suspended portion 2534 are connected to each other and enclose a first opening 2535 .

[0087] In this embodiment, the first suspension portion 2533 and the second suspension portion 2534 of the third part 253 are arranged to form a first opening 2535. The first opening 2535 can provide a high sound velocity area at the end of the resonator for energy limitation, thereby improving the Q value of the resonator. At the same time, the first opening 2535 is shared by two resonators, which can reduce the layout area to a certain extent and realize the miniaturization of the resonator. It should be understood that the first opening 2535 can be a closed opening of any shape, such as a circle, an ellipse or a quadrilateral.

[0088] like Figure 5 As shown, in some embodiments, the shape of the first opening 2535 is a rectangle. In this embodiment, the shape of the first opening 2535 is preferably set to be a rectangle, which can improve the effect of suppressing the resonance of the stray mode, thereby effectively avoiding the resonance phenomenon of the stray mode.

[0089] like Figure 2 and Figure 3As shown, in some embodiments, the connection portion 201 of the first electrode finger 23 and the middle portion 203 of the first electrode finger 23 are connected at an angle, the middle portion 203 of the first electrode finger 23 and the main body 202 of the first electrode finger 23 are connected at an angle, and the first bus bar 21, the connection portion 201 of the first electrode finger 23 and the middle portion 203 of the first electrode finger 23 form a second opening 231, and the second opening 231 faces the direction from the connection portion 201 to the middle portion 203 in the same first electrode finger 23. In this way, the shape of the end of the main body 202 of the first electrode finger 23 and the first bus bar 21 (the first gap area G1) can be changed, so that the stray mode, especially the stray mode in the gap area, can be effectively suppressed. It can be understood that the angle can be an acute angle, an obtuse angle, or a right angle, so that the first electrode finger 23 can have a bent shape in the first gap area G1.

[0090] like Figure 2 and Figure 3 As shown, in some embodiments, the connecting portion 201 of the second electrode finger 24 and the middle portion 203 of the second electrode finger 24 are connected at an angle, the middle portion 203 of the second electrode finger 24 and the main body 202 of the second electrode finger 24 are connected at an angle, and the second bus bar 22, the connecting portion 201 of the second electrode finger 24 and the middle portion 203 of the second electrode finger 24 form a third opening 241, and the third opening 241 faces the direction from the connecting portion 201 to the middle portion 203 in the same second electrode finger 24. In this way, the shape of the end of the main body 202 of the second electrode finger 24 and the second bus bar 22 (the second gap area G2) can be changed, so that the stray mode can be effectively suppressed. It can be understood that the angle can be an acute angle, an obtuse angle, or a right angle, so that the second electrode finger 24 can have a bent shape in the second gap area G2.

[0091] like Figure 3 and Figure 4 As shown, in a specific embodiment, the second opening 231 is oriented in a direction away from the main body 202 of the first electrode finger 23, and the third opening 241 is oriented in a direction away from the main body 202 of the second electrode finger 24, so that the second opening 231 and the third opening 241 are oriented in opposite directions, thereby effectively suppressing the stray modes in the gap area (the first gap area G1 and the second gap area G2).

[0092] like Figure 2 , Figure 3 and Figure 4As shown, in some embodiments, the resonant frequencies of the first resonant unit 204 and the second resonant unit 205 are the same. Specifically, the distance (pitch1) between the center line of the first electrode finger 23 and the center line of the suspension electrode 25 in the first resonant unit 204 is the same as the distance (pitch2) between the center line of the second electrode finger 24 and the center line of the suspension electrode 25 in the second resonant unit 205. In some embodiments, at least one of the aperture, duty cycle, and number of fingers between the first resonant unit 204 and the second resonant unit 205 may also be the same. In a specific embodiment, the pitch of the first resonant unit 204 and the second resonant unit 205 is the same, and further, the aperture, duty cycle, and number of fingers of the first resonant unit 204 and the second resonant unit 205 are also the same.

[0093] like Figure 2 and Figure 5 As shown, in some embodiments, the suspension electrode 25 includes a suspension electrode unit 254 , and the suspension electrode unit 254 is alternately arranged with the first electrode fingers 23 and the second electrode fingers 24 along the second direction and overlaps with each other.

[0094] It can be understood that the suspension electrode units 254 are alternately arranged with the main body 202 of the first electrode finger 23 along the second direction and overlap with each other to form the first resonance unit 204, and the suspension electrode units 254 are alternately arranged with the main body 202 of the second electrode finger 24 along the second direction and overlap with each other to form the second resonance unit 205. At the same time, the suspension electrode unit 254 can have the structure of the suspension electrode 25 described above.

[0095] like Figure 1 , Figure 2 and Figure 5 As shown, in a specific embodiment, the suspension electrode unit 254 includes a first portion 251, a third portion 253, and a second portion 252 which are sequentially connected along a first direction. The first portion 251 and the second portion 252 are respectively located on both sides of the third portion 253 along the first direction. The first portion 251 and the third portion 253 are arranged at an angle, and the second portion 252 and the third portion 253 are arranged at an angle. In this way, in the region between the first resonance unit 204 and the second resonance unit 205, the ends of the first portion 251 and the ends of the third portion 253 and the second portion 252 form a bent shape, thereby suppressing the heterogeneous mode generated in the region between the first resonance unit 204 and the second resonance unit 205 to a certain extent.

[0096] It should be understood that in the embodiment where the suspension electrode 25 includes a suspension electrode unit 254 , the resonator 1 can be regarded as a resonator group composed of two identical resonators in cascade connection, and the common bus bar is removed from the resonator group and then cascaded through the third part 253 .

[0097] In some embodiments, the first resonance unit 204 and the second resonance unit 205 may share a reflection grating, which may reduce the layout area to a certain extent. Of course, the first resonance unit 204 and the second resonance unit 205 may also have two reflection gratings respectively, which is not specifically limited in this embodiment.

[0098] like Figure 6 and Figure 7 As shown, in some embodiments, the suspension electrode 25 includes at least two suspension electrode units 254, and the at least two suspension electrode units 254 are arranged along the first direction; the suspension electrode units 254 close to the first bus bar 21 are alternately arranged with the first electrode fingers 23 along the second direction and overlap with each other; the suspension electrode units 254 close to the second bus bar 22 are alternately arranged with the second electrode fingers 24 along the second direction and overlap with each other; two adjacent suspension electrode units 254 are alternately arranged along the second direction and overlap with each other to form a third resonance unit 206.

[0099] It can be understood that the suspension electrode 25 includes a plurality of suspension electrode units 254 arranged along the first direction, such as two, three or four, and the present embodiment does not specifically limit the number of the suspension electrode units 254. The suspension electrode units 254 close to the first bus bar 21 are alternately arranged with the main body 202 of the first electrode finger 23 along the second direction and overlap with each other, and the suspension electrode units 254 close to the second bus bar 22 are alternately arranged with the main body 202 of the second electrode finger 24 along the second direction and overlap with each other.

[0100] Here, the suspension electrode 25 includes two suspension electrode units 254 as an example for description.

[0101] In the embodiment where the suspension electrode 25 includes two suspension electrode units 254, the two suspension electrode units 254 are respectively defined as a first suspension electrode unit 254a and a second suspension electrode unit 254b. The first suspension electrode unit 254a and the second suspension electrode unit 254b both include a first portion 251, a second portion 252, and a third portion 253 located between the first portion 251 and the second portion 252. The first portion 251 of the first suspension electrode unit 254a and the main body 202 of the first electrode finger 23 are alternately arranged along the second direction and overlap with each other to form a first resonance unit 204. The second portion 252 of the second suspension electrode unit 254b and the main body 202 of the second electrode finger 24 are alternately arranged along the second direction and overlap with each other to form a second resonance unit 205. The second portion 252 of the first suspension electrode unit 254a and the first portion 251 of the second suspension electrode unit 254b are alternately arranged along the second direction and overlap with each other to form a third resonance unit 206.

[0102] In a specific embodiment, in two adjacent rows of suspension electrode units 254 along the second direction, two adjacent suspension electrode units 254 along the second direction are connected via a third portion 253 to conduct the two adjacent suspension electrode units 254 along the second direction, thereby effectively ensuring the integrity of the resonant cavity in the resonator 1.

[0103] Combination Figure 6 , Figure 7 and Figure 8 In the embodiment in which the suspension electrode 25 includes two suspension electrode units 254, the embodiment of the present application further provides a comparative example, and the embodiment in which the suspension electrode 25 includes two suspension electrode units 254 is recorded as embodiment 1, and the embodiment 1 is compared with the comparative example to make the effect of the embodiment of the present application more intuitive.

[0104] Combination Figure 6 and Figure 8 In the comparative example, the resonator cascade group includes three identical resonators, and two adjacent resonators are cascaded through a common bus bar. The length of the bus bar extending along the second direction in the comparative example is equal to the length of the bus bar (the first bus bar and the second bus bar) in the embodiment extending along the second direction. Embodiment 1 and the comparative example have the same structural parameters (aperture, pitch, duty cycle, etc.).

[0105] On this basis, the areas of Example 1 and the comparative example are compared. Specifically, in combination with relevant technologies, the length of Example 1 in the aperture direction is L1, and the length in the aperture direction is L2. By comparing L1 and L2, it is calculated that the length of Example 1 is reduced by about (L1-L2) / L1*100%=(128-118) / 128*100%=7.8% compared with the comparative example. Therefore, it can be concluded that the layout area of ​​the resonator 1 of the embodiment is significantly smaller than the layout area of ​​the resonator cascade group of the comparative example.

[0106] It can be seen that the first embodiment can reduce the area by about 7% under the same circuit structure by changing the structure of the cascade resonator of the comparative example and optimizing the internal finger arrangement, which is conducive to the miniaturization of the cascade resonator and helps to optimize the layout area for the filter circuit that needs to use multiple cascade structures.

[0107] Fig. 9 is a schematic diagram of the admittance curve of the first embodiment, Fig.10 is a schematic diagram of the admittance curve of the comparative example, wherein the solid line is the admittance curve and the dotted line is the real part of the admittance curve. Fig. 9 and Fig.10 It can be seen that, compared with the comparative example, the amplitude of the stray mode in the first embodiment is well suppressed, which means that the first embodiment can suppress the stray mode in the gap region and effectively prevent the resonance phenomenon of the stray mode.

[0108] Combination Figure 1 In some embodiments, the piezoelectric substrate 10 includes a substrate and a piezoelectric layer, the piezoelectric layer is disposed on the substrate, the interdigital transducer 20 is formed on the piezoelectric layer, and the temperature coefficient of the substrate is smaller than the temperature coefficient of the piezoelectric layer. In this way, the performance and stability of the resonator 1 can be improved.

[0109] In some embodiments, the substrate may be single crystal silicon, polycrystalline silicon, quartz, glass, or the like.

[0110] Combination Figure 1 In some embodiments, the thickness of the substrate is greater than that of the piezoelectric layer, which helps to improve the stability of the piezoelectric substrate 10. The acoustic velocity or acoustic impedance of the substrate is higher than that of the piezoelectric layer to reduce the longitudinal leakage of the acoustic wave energy and improve the Q value of the resonator.

[0111] Combination Figure 1 In other embodiments, the piezoelectric substrate 10 may be a piezoelectric layer (piezoelectric substrate), the piezoelectric layer may be a single-layer or multi-layer piezoelectric material, specifically aluminum nitride, zinc oxide, lead zirconate titanate (PZT) or a rare earth element doped material with a certain atomic ratio of the above materials, the piezoelectric layer may also be a single crystal piezoelectric material, for example, single crystal aluminum nitride, lithium niobate, lithium tantalate, quartz, etc., and this embodiment does not impose any specific restrictions on this.

[0112] Combination Figure 1 In some embodiments, the piezoelectric substrate 10 further includes an intermediate layer, which is disposed between the piezoelectric layer and the substrate; the intermediate layer includes at least one low acoustic velocity layer or a low acoustic impedance layer, and the substrate is a high acoustic velocity layer or a high acoustic impedance layer.

[0113] In this embodiment, an intermediate layer is provided between the piezoelectric layer and the substrate, the intermediate layer includes at least one low acoustic velocity layer or low acoustic impedance layer, the acoustic velocity or acoustic impedance of the intermediate layer is less than the acoustic velocity or acoustic impedance of the piezoelectric layer, the substrate is a high acoustic velocity layer or a high acoustic impedance layer, and the arrangement of the substrate and the intermediate layer can not only play a role in temperature compensation for the piezoelectric layer, but also form an acoustic reflection structure under the piezoelectric layer, reduce the longitudinal leakage of acoustic wave energy, and improve the Q value of the resonator. The longitudinal direction is the thickness direction of the piezoelectric layer.

[0114] Combination Figure 1 and Figure 2In some embodiments, the resonator 1 further includes a temperature compensation layer, which is disposed on the piezoelectric substrate 10 and covers at least the first resonance unit 204 and the second resonance unit 205. In this embodiment, a temperature compensation layer is provided, and the temperature compensation layer at least covers the first resonance unit 204 and the second resonance unit 205, which can reduce the frequency shift caused by temperature change, effectively improve the temperature stability of the filter, and improve the Q value of the resonator. Among them, the temperature compensation layer at least covers the first resonance unit 204 and the second resonance unit 205. It can be understood that the temperature compensation layer can completely cover the IDT 20, or it can not completely cover the IDT 20, for example, only covers the area where the first resonance unit 204 and the second resonance unit 205 are located, or only covers the area where the first electrode finger 23 and the second electrode finger 24 of the IDT 20 are located, while the first bus bar 21 and the second bus bar 22 are not covered by the temperature compensation layer.

[0115] In some embodiments, the temperature compensation layer may be a material having a positive temperature compensation coefficient, such as silicon oxide, silicon oxide doped with other elements, etc., to adjust the frequency temperature coefficient of the resonator 1. For example, the material of the temperature compensation layer may be at least one of dielectric materials having a positive temperature compensation coefficient, such as silicon oxide, silicon nitride, silicon oxynitride, tellurium dioxide, silicon oxyfluoride, etc. Among them, the material of the temperature compensation layer is usually one of the above materials, that is, the material of the temperature compensation layer is a single material. Of course, in some feasible embodiments, the material of the temperature compensation layer may also be a mixed material, in which case the material of the temperature compensation layer may be a mixture of any of the above materials, or a mixture of one or more of the above materials with other materials.

[0116] Combination Figure 2 In some embodiments, the first bus bar 21, the second bus bar 22, the first electrode finger 23 and the second electrode finger 24 can all be made of conductive materials, such as a single metal material or a composite or alloy material of different metals. Optionally, the above materials can be aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, etc. or a composite of the above metals or one of their alloys.

[0117] Combination Figure 2 and Figure 3 In some embodiments, the first resonance unit 204 and the second resonance unit 205 both include a cross-transduction area C1 and two edge areas C2, the two edge areas C2 are located on opposite sides of the cross-transduction area C1 along the first direction, and a sound velocity adjustment structure is provided in the cross-transduction area C1, or a sound velocity adjustment structure is provided in the edge area C2 to increase the sound velocity of the cross-transduction area C1 or reduce the sound velocity of the edge area C2, thereby increasing the sound velocity difference between the cross-transduction area C1 and the edge areas C2 on both sides thereof, reducing the lateral loss of the sound wave, and helping to further suppress the heterogeneous mode.

[0118] Among them, a sound velocity adjustment structure is set in the cross transduction area C1, including setting a high sound velocity layer in the cross transduction area C1; the sound velocity adjustment structure is set in the edge area C2, including performing one or more combined processing methods of widening, thickening and adding a dielectric layer on the first electrode finger 23 and the second electrode finger 24 at the edge area C2, so as to form a low sound velocity layer or a low sound velocity structure at the position of the first electrode finger 23 and the second electrode finger 24 corresponding to the edge area C2.

[0119] It should be noted that the resonator of the embodiment of the present application can be applicable to surface acoustic wave resonators with higher Q values, such as temperature compensated surface acoustic wave resonators (TC-SAW), piezoelectric thin film SAW resonators, and other resonators with interdigital transducers 20, and the present application does not limit this.

[0120] Combination Figure 1 The embodiment of the present application also provides a filter, including the resonator 1 in any of the above-mentioned embodiments, which can reduce the layout area, suppress the stray mode in the gap area of ​​the resonator, and effectively avoid the resonance phenomenon of the stray mode when the resonator is cascaded, thereby improving the working performance of the filter.

[0121] In some implementations, the filter may be a ladder-type filter or other types of filters, which are not specifically limited in this embodiment.

[0122] Combination Figure 1 The embodiment of the present application also provides a radio frequency front-end module, including the resonator 1 in any of the above-mentioned embodiments, which can reduce the layout area, suppress the stray modes in the gap area of ​​the resonator, and effectively avoid the resonance phenomenon of the stray modes when the resonators are cascaded, thereby improving the working performance of the radio frequency front-end module.

[0123] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural changes made by using the contents of the present application specification and drawings under the application concept of the present application, or directly / indirectly used in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A resonator, characterized in that: include: Piezoelectric substrate; an interdigital transducer formed on the piezoelectric substrate; The IDT comprises a first bus bar and a second bus bar arranged opposite to each other along a first direction, and at least one first electrode finger, at least one second electrode finger and at least one suspension electrode located between the first bus bar and the second bus bar, wherein the first electrode finger, the suspension electrode and the second electrode finger are arranged at intervals along a second direction, and the first electrode finger and the second electrode finger are staggered in the second direction, and the first direction and the second direction are orthogonal; The first electrode finger and the second electrode finger each include a connecting portion, a main portion, and an intermediate portion connected between the connecting portion and the main portion, the connecting portion of the first electrode finger is connected to the first bus bar, and the connecting portion of the second electrode finger is connected to the second bus bar; In the first direction, the connecting portion and the main body are respectively located on two sides of the middle portion; In the second direction, the floating electrodes and the main body of the first electrode fingers are alternately arranged and overlapped to form a first resonance unit, and the floating electrodes and the main body of the second electrode fingers are alternately arranged and overlapped to form a second resonance unit.

2. The resonator according to claim 1, characterized in that The suspension electrode comprises a first portion, a second portion and a third portion, and in the first direction, the first portion and the second portion are respectively located on both sides of the third portion; The first portion and the main body of the first electrode finger are alternately arranged along the second direction and overlap with each other to form the first resonance unit, and the second portion and the main body of the second electrode finger are alternately arranged along the second direction and overlap with each other to form the second resonance unit.

3. The resonator according to claim 2, characterized in that The connecting portion of the first electrode finger, the first portion and the main body of the second electrode finger are sequentially arranged in intervals along the first direction; and / or, The connecting portion of the second electrode finger, the second portion, and the main body of the first electrode finger are sequentially arranged at intervals along the first direction.

4. The resonator according to claim 2, characterized in that The third portion is disposed spaced apart from the middle portion of the first electrode finger and the middle portion of the second electrode finger along the first direction.

5. The resonator according to claim 2, characterized in that In the second direction, two adjacent floating electrodes are connected via the third portion.

6. The resonator according to claim 2, characterized in that The width of the third portion along the first direction is greater than the width of the first portion along the second direction; and / or, A width of the third portion along the first direction is greater than a width of the second portion along the second direction.

7. The resonator according to claim 2, characterized in that The third part includes a first suspension portion and a second suspension portion, and the first suspension portion and the second suspension portion are connected to each other and enclose a first opening.

8. The resonator according to claim 7, characterized in that The first opening is in a rectangular shape.

9. The resonator according to any one of claims 1 to 8, characterized in that: The connecting portion and the middle portion are connected at an angle, and the middle portion and the main body portion are connected at an angle; The first bus bar, the connecting portion of the first electrode finger and the middle portion of the first electrode finger form a second opening, and the second opening is oriented in the direction from the connecting portion to the middle portion of the same first electrode finger; and / or the second bus bar, the connecting portion of the second electrode finger and the middle portion of the second electrode finger form a third opening, and the third opening is oriented in the direction from the connecting portion to the middle portion of the same second electrode finger.

10. The resonator according to any one of claims 1 to 8, characterized in that: The suspension electrode includes a suspension electrode unit, and the suspension electrode unit is alternately arranged with the first electrode fingers and the second electrode fingers along the second direction and overlaps with each other.

11. The resonator according to any one of claims 1 to 8, characterized in that: The suspension electrode comprises at least two suspension electrode units, and the at least two suspension electrode units are arranged along the first direction; The floating electrode units close to the first bus bar are alternately arranged with the first electrode fingers along the second direction and overlap with each other; The floating electrode units close to the second bus bar are alternately arranged with the second electrode fingers along the second direction and overlap with each other; Two adjacent floating electrode units are alternately arranged along the second direction and overlap each other to form a third resonance unit.

12. The resonator according to any one of claims 1 to 8, characterized in that: The piezoelectric substrate comprises a substrate and a piezoelectric layer, the piezoelectric layer is arranged on the substrate, and the interdigital transducer is formed on the piezoelectric layer; The temperature coefficient of the substrate is smaller than the temperature coefficient of the piezoelectric layer, and / or the thickness of the substrate is larger than the thickness of the piezoelectric layer.

13. The resonator according to claim 12, characterized in that The piezoelectric substrate further comprises an intermediate layer, wherein the intermediate layer is arranged between the piezoelectric layer and the substrate; The intermediate layer includes at least one low acoustic velocity layer or low acoustic impedance layer, and the substrate is a high acoustic velocity layer or a high acoustic impedance layer.

14. The resonator according to any one of claims 1 to 8, characterized in that: The resonator further includes a temperature compensation layer, which is disposed on the piezoelectric substrate and covers at least the first resonance unit and the second resonance unit.

15. The resonator according to any one of claims 1 to 8, characterized in that The first resonance unit and the second resonance unit have the same resonance frequency.

16. A filter, characterized in that: Comprising a resonator as claimed in any one of claims 1 to 15.

17. A radio frequency front-end module, characterized in that: Comprising a resonator as claimed in any one of claims 1 to 15.

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