Resonator and preparation method therefor, filter, communication chip and electronic device

Abstract

A resonator (30) and a preparation method therefor, a filter (21), a communication chip (20) and an electronic device, which relate to the field of communications. In a transducer (32) of the resonator (30), each first dummy finger (325) and / or each first interdigital finger (324) are / is provided with a first tip (3251). In a direction perpendicular to the surface of a piezoelectric material layer (31), the first tip (3251) forms a first projection on the surface of the piezoelectric material layer (31); and the vertical spacing between a first edge (3253) of a first projection pattern (3252) corresponding to the first projection and a first bus bar (321) on the surface of the piezoelectric material layer (31) gradually decreases or increases along the first edge (3253). By means of providing tips at electrode ends of the transducer (32), a transverse mode of an anti-resonance point can be effectively suppressed, thereby improving the passband performance of the filter (21) and reducing insertion loss.

Description

A resonator and its fabrication method, a filter, a communication chip, and electronic equipment.

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411654211.7, filed on January 21, 2025, with the title “A Resonator, Filter, Communication Chip and Electronic Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, specifically to a resonator and its fabrication method, a filter, a communication chip, and an electronic device. Background Technology

[0004] Electronic devices (such as mobile phones, tablets, smart wearable devices, and in-vehicle terminals) typically incorporate filters to improve signal quality. These filters include resonators, and enhancing the performance of the resonator is crucial for improving overall filter performance. Summary of the Invention

[0005] This application provides a resonator and its fabrication method, a filter, a communication chip, and an electronic device. By improving the structure of the resonator, the transverse mode of the anti-resonance point can be better suppressed, thereby improving the passband characteristics of the filter and reducing insertion loss.

[0006] In a first aspect, embodiments of this application provide a resonator, including: a piezoelectric material layer;

[0007] A transducer, wherein the transducer is disposed on the surface of the piezoelectric material layer, the transducer comprising:

[0008] A first busbar and a second busbar are provided at an interval;

[0009] A first forked finger and a second forked finger are disposed at intervals between the first busbar and the second busbar. The first forked finger is connected to the first busbar, and the second forked finger is connected to the second busbar.

[0010] The first pseudo-finger corresponds to the first interdigitated finger. The first pseudo-finger is disposed on the side of the second busbar close to the first busbar. The end of the first pseudo-finger away from the second busbar and the end of the first interdigitated finger away from the first busbar are spaced apart in the length direction of the first interdigitated finger. The end of the first pseudo-finger away from the second busbar and / or the end of the first interdigitated finger away from the first busbar are provided with a first tip.

[0011] Along a direction perpendicular to the surface of the piezoelectric material layer, the first tip forms a first projection on the surface of the piezoelectric material layer; the first side of the first projection pattern corresponding to the first projection gradually decreases or increases in perpendicular distance between the first side and the first busbar on the surface of the piezoelectric material layer; the first side is the side corresponding to the end face of the first tip.

[0012] In this embodiment, by setting the end shape of the first forked finger and / or the first prosthetic finger to a pointed tip, the end mass load can be changed, reducing the effective distance between the high and low sound velocity regions of the gap between the forked finger and the prosthetic finger, thereby better suppressing transverse mode.

[0013] Optionally, when both the first prosthetic finger and the first interdigitated finger are provided with the first tip, the changing trend of the vertical distance between the first side formed by the first tip of the first prosthetic finger and the first busbar is the same as the changing trend of the vertical distance between the first side formed by the first tip of the first interdigitated finger and the first busbar.

[0014] In this embodiment, the changing trend of the vertical distance between the first edge formed by the first tip of the first pseudofinger and the first busbar is the same as the changing trend of the vertical distance between the first edge formed by the first tip of the first interdigital finger and the first busbar. This makes the excessive change trend of the sound velocity of the piezoelectric material layer in the corresponding area of ​​the tips of the first pseudofinger and the first interdigital finger exactly opposite, which can reduce the effective distance between the two ends of the high and low sound velocity regions of the gap area between the first interdigital finger and the first pseudofinger, thereby better suppressing the transverse mode.

[0015] Optionally, the first side forms an acute angle α with the length direction of the first interdigitated finger or the first prosthetic finger, where 40°≤α≤85°.

[0016] Optionally, the first side forms an acute angle α with the length direction of the first interdigitated finger or the first prosthetic finger, where 55°≤α≤75°.

[0017] Optionally, the first side forms an acute angle α with the length direction of the first interdigitated finger or the first prosthetic finger, where 60°≤α≤65°.

[0018] In this embodiment, a tip angle less than 40° may generate tip discharge, while an angle greater than 85° results in an overly gentle tip inclination, limiting its effect on changing the tip mass load. Therefore, the acute angle α can be limited to a range of 40° ≤ α ≤ 85°. To achieve a better effect on changing the tip mass load, the acute angle α can be further limited to a range of 55° ≤ α ≤ 75°. To further improve the effect on changing the tip mass load, the acute angle α can be further limited to a range of 60° ≤ α ≤ 65°.

[0019] Optionally, the minimum distance between the end of the first spur finger away from the second busbar and the end of the first interdigital finger away from the first busbar in the length direction of the first interdigital finger or the first spur finger is 0.15λ to 0.25λ.

[0020] Wherein, λ is twice the shortest distance between the center lines of the first interdigitated finger and the second interdigitated finger. In this embodiment, setting the gap (Gap) between the first prosthetic finger and the first interdigitated finger to 0.15λ to 0.25λ can better suppress the second harmonic. According to simulation results, when the value corresponding to the gap between the interdigitated finger and the prosthetic finger is increased to 0.15λ to 0.25λ, the transverse mode can still be effectively suppressed.

[0021] Optionally, in any of the first projection patterns, the distance difference between the point on the first side furthest from the first busbar and the point on the first side closest to the first busbar in the length direction of the first interdigit is 0.1λ to 0.25λ.

[0022] Along the direction parallel to the piezoelectric material layer and parallel to the length of the first busbar, the width of the first pseudo-finger is 0.2λ to 0.3λ;

[0023] Along the length of the first prosthetic finger, the minimum distance between the end face of the first tip of the first prosthetic finger and the end of the first prosthetic finger near the second busbar is 0.15λ to 0.25λ.

[0024] In this embodiment, the dimensions are limited as described above. The length and width of the first pseudo-finger are moderate, which can ensure that the first pseudo-finger has sufficient length along the length direction perpendicular to the second busbar so that the sound wave is scattered on the piezoelectric material layer near the first pseudo-finger. At the same time, it can also avoid the length and width of the first pseudo-finger being too large.

[0025] Furthermore, the size limitation of the first tip limits the corresponding sound velocity variation region to a better range, which can better suppress the transverse mode between the resonant point and the anti-resonant point.

[0026] Optionally, the transducer further includes a second pseudo-finger, which corresponds to the second forked finger. The second pseudo-finger is disposed on the side of the first busbar closer to the second busbar. The end of the second pseudo-finger away from the first busbar and the end of the second forked finger away from the second busbar are spaced apart along the length of the second forked finger, and the end of the second pseudo-finger away from the first busbar and / or the end of the second forked finger away from the second busbar are provided with a second tip.

[0027] Along a direction perpendicular to the surface of the piezoelectric material layer, the second tip forms a second projection on the surface of the piezoelectric material layer; the second side of the second projection pattern corresponding to the second projection gradually decreases or increases in perpendicular distance between the second side and the second busbar on the surface of the piezoelectric material layer; the second side is the side corresponding to the end face of the second tip.

[0028] In this embodiment, the second pseudo-finger can reduce the sound velocity of a portion of the piezoelectric material layer corresponding to the second pseudo-finger, causing the sound waves on the piezoelectric material layer corresponding to the transmission channel to be reflected at the location of the second pseudo-finger, thus preventing the sound waves from leaking out of the first busbar. Furthermore, setting the end shape of the second forked finger and / or the second pseudo-finger to a pointed shape can change the end mass load, reducing the effective distance between the high and low sound velocity regions of the gap between the second forked finger and the second pseudo-finger, thereby further suppressing transverse modes.

[0029] Optionally, when both the second pseudofinger and the second interdigital finger are provided with a second tip, the changing trend of the distance between the second side formed by the second tip of the second pseudofinger and the second busbar is the same as the changing trend of the distance between the second side formed by the second tip of the second interdigital finger and the second busbar.

[0030] In this embodiment, the variation trend of the vertical distance between the second side formed by the second tip of the second pseudofinger and the second busbar is the same as the variation trend of the vertical distance between the second side formed by the second tip of the second forked finger and the second busbar. This makes the excessive variation trend of the sound velocity of the piezoelectric material layer in the corresponding area of ​​the tips of the second pseudofinger and the second forked finger exactly opposite, which can reduce the effective distance between the two ends of the high and low sound velocity regions of the gap area between the second forked finger and the second pseudofinger, thereby better suppressing the transverse mode.

[0031] Optionally, the second side forms an acute angle β with the length direction of the second interdigitated finger or the second pseudo-finger, where 40°≤β≤85°.

[0032] Optionally, the second side forms an acute angle β with the length direction of the second interdigitated finger or the second pseudo-finger, where 55°≤β≤75°.

[0033] Optionally, the second side forms an angle β with the length direction of the second interdigitated finger or the second pseudo-finger, where 60°≤β≤65°.

[0034] In this embodiment, a tip angle less than 40° may generate tip discharge, while an angle greater than 85° results in an overly gentle tip inclination, limiting its effect on changing the tip mass load. Therefore, the acute angle α can be limited to a range of 40° ≤ β ≤ 85°. To achieve a better effect on changing the tip mass load, the acute angle α can be further limited to a range of 55° ≤ β ≤ 75°. To further improve the effect on changing the tip mass load, the acute angle α can be further limited to a range of 60° ≤ β ≤ 65°.

[0035] Optionally, the minimum distance between the end of the second pseudofinger away from the first busbar and the end of the second interdigitated finger away from the second busbar in the length direction of the second interdigitated finger or the second pseudofinger is 0.15λ to 0.25λ.

[0036] Wherein, λ is twice the shortest distance between the center line of the first interdigitated finger and the center line of the second interdigitated finger.

[0037] In this embodiment, setting the gap (Gap) between the second prosthetic finger and the second interdigital finger to 0.15λ to 0.25λ can better suppress the second harmonic.

[0038] Optionally, in the second projection pattern, the distance difference between the point on the second side furthest from the first busbar and the point on the second side closest to the first busbar in the length direction of the second interdigit is 0.1λ to 0.25λ.

[0039] Along the direction parallel to the piezoelectric material layer and parallel to the length of the first busbar, the width of the second pseudo-finger is 0.2λ to 0.3λ;

[0040] Along the length of the second prosthetic finger, the minimum distance between the end face of the second tip of the second prosthetic finger and the end of the second prosthetic finger near the first busbar is 0.15λ to 0.25λ.

[0041] In this embodiment, the dimensions are limited as described above. The length and width of the second pseudo-finger are moderate, which can ensure that the second pseudo-finger has sufficient length along the length direction perpendicular to the second busbar so that the sound wave is scattered on the piezoelectric material layer near the second pseudo-finger. At the same time, it can also avoid the second pseudo-finger being too long and wide.

[0042] Furthermore, the size limitation of the second tip limits the corresponding sound velocity variation region to a better range, which can better suppress the transverse mode between the resonant point and the anti-resonant point.

[0043] Optionally, the length directions of the first busbar and the second busbar are parallel, and the widths of the first busbar and the second busbar are 0.1λ to 0.25λ.

[0044] Optionally, the transducer further includes a first auxiliary busbar and a second auxiliary busbar; wherein,

[0045] The first auxiliary busbar is disposed on the side of the first busbar away from the second busbar. The first auxiliary busbar is parallel to and spaced apart from the first busbar, and the first auxiliary busbar is connected to the first busbar through a first connecting post.

[0046] The second auxiliary busbar is disposed on the side of the second busbar away from the first busbar. The second auxiliary busbar is parallel to and spaced apart from the second busbar, and the second auxiliary busbar is connected to the second busbar through a second connecting post.

[0047] In this embodiment, the sound velocity of the piezoelectric material layer corresponding to the first auxiliary busbar can be different from the sound velocity of the piezoelectric material layer between the first auxiliary busbar and the first busbar. Sound waves can be reflected on the piezoelectric material layer corresponding to the first auxiliary busbar to further prevent sound wave leakage. Similarly, the sound velocity of the piezoelectric material layer corresponding to the second auxiliary busbar can be different from the sound velocity of the piezoelectric material layer between the second auxiliary busbar and the second busbar. Sound waves can be reflected on the piezoelectric material layer corresponding to the second auxiliary busbar to further prevent sound wave leakage.

[0048] Optionally, the first connecting post is an extension of the first interdigitated finger in the length direction, and the second connecting post is an extension of the second interdigitated finger in the length direction.

[0049] In this embodiment, the first connecting post can better prevent the coupling of the acoustic wave at the anti-resonance point of the first resonance (the acoustic wave corresponding to the Rayleigh transverse mode) and the acoustic wave corresponding to the second resonance (the acoustic wave corresponding to the SH mode), further reducing noise and further improving communication performance.

[0050] Optionally, the transducer further includes a first reverse spur finger, which is disposed on the side of the second busbar opposite to the first busbar; and / or,

[0051] The transducer also includes a second reverse pseudofinger, which is disposed on the side of the first busbar opposite to the second busbar.

[0052] In this embodiment, the first reverse pseudo-finger can increase the density of the second busbar on the side away from the transmission channel, thereby preventing the formation of acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode). This reduces clutter formed by the coupling between the acoustic waves and the acoustic waves corresponding to the second resonance, improving communication performance. Specifically, the sound velocity of the piezoelectric material layer where the first reverse pseudo-finger is located is lower than the sound velocity of the piezoelectric material layer on the side of the first reverse pseudo-finger away from the transmission channel. Therefore, acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode) and the acoustic waves corresponding to the second resonance (acoustic waves corresponding to the SH mode) will be scattered (e.g., reflected and / or refracted) on the piezoelectric material layer near the first reverse pseudo-finger, preventing the coupling between the acoustic waves with frequencies higher than the anti-resonance point of the first resonance and the acoustic waves corresponding to the second resonance, further reducing clutter and further improving communication performance. Similarly, the second reverse pseudo-finger can increase the density of the first busbar on the side away from the transmission channel, thereby preventing the formation of acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode). This reduces clutter formed by the coupling between this acoustic wave and the acoustic wave corresponding to the second resonance, improving communication performance. Furthermore, the sound velocity in the piezoelectric material layer where the second reverse pseudo-finger is located is lower than the sound velocity in the piezoelectric material layer on the side of the second reverse pseudo-finger away from the transmission channel. Therefore, acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode) and the acoustic wave corresponding to the second resonance (acoustic waves corresponding to the SH mode) will be scattered (e.g., reflected and / or refracted) on the piezoelectric material layer near the second reverse pseudo-finger, preventing the coupling between the acoustic waves with frequencies higher than the anti-resonance point of the first resonance and the acoustic wave corresponding to the second resonance, further reducing clutter and improving communication performance.

[0053] Optionally, the transducer further includes a first auxiliary busbar and a second auxiliary busbar; wherein,

[0054] The first auxiliary busbar is disposed on the side of the first busbar opposite to the second busbar. The first auxiliary busbar is parallel to and spaced apart from the first busbar, and the first auxiliary busbar is connected to the first busbar through a first connecting post. The second reverse dummy finger is disposed between the first busbar and the first auxiliary busbar.

[0055] The second auxiliary busbar is disposed on the side of the second busbar away from the first busbar. The second auxiliary busbar is parallel to and spaced apart from the second busbar, and the second auxiliary busbar is connected to the second busbar through a second connecting post. The first reverse dummy finger is disposed between the second busbar and the second auxiliary busbar.

[0056] In this embodiment, the sound velocity of the piezoelectric material layer corresponding to the first auxiliary busbar can be different from the sound velocity of the piezoelectric material layer between the first auxiliary busbar and the first busbar. Sound waves can be reflected on the piezoelectric material layer corresponding to the first auxiliary busbar to further prevent sound wave leakage. Similarly, the sound velocity of the piezoelectric material layer corresponding to the second auxiliary busbar can be different from the sound velocity of the piezoelectric material layer between the second auxiliary busbar and the second busbar. Sound waves can be reflected on the piezoelectric material layer corresponding to the second auxiliary busbar to further prevent sound wave leakage.

[0057] Optionally, the distance between the first busbar and the first auxiliary busbar is 0.6λ to 1.2λ, and the distance between the second busbar and the second auxiliary busbar is 0.6λ to 1.2λ; wherein λ is twice the shortest distance between the center line of the first interdigitated finger and the center line of the second interdigitated finger.

[0058] Optionally, the transducer further includes an expansion portion and / or a protrusion; wherein,

[0059] The expansion portion and / or the protrusion are provided at both the position of the first interdigital finger near the first busbar and the position of the first interdigital finger near the second busbar;

[0060] The expansion portion and / or the protrusion are provided at the positions of the second forked finger near the first busbar and the positions of the second forked finger near the second busbar.

[0061] In this embodiment, the size of the expansion portion is larger than the size of other positions of the first interdigitate, causing the sound velocity of the piezoelectric material layer corresponding to the expansion portion to be lower than the sound velocity of the piezoelectric material layer corresponding to the first interdigitate on both sides. This allows sound waves to be reflected in this region, preventing sound waves from leaking to the outside of the first and second busbars, thereby better suppressing transverse modes. The effect of the second interdigitate is similar.

[0062] Optionally, along the length direction of the first busbar, the width of the expansion portion is greater than the width of the first interdigit or the second interdigit; the protrusion is disposed on the side of the first interdigit or the second interdigit away from the piezoelectric material layer.

[0063] Optionally, the protrusion is located at the position of the expansion portion.

[0064] In this embodiment, the protrusions can increase the sound velocity difference of the corresponding piezoelectric material layers, thereby better suppressing transverse modes.

[0065] Optionally, the length of the expansion portion is 0.6λ to 1.2λ, and the width of the expansion portion is 0.05µm to 0.15µm larger than the width of the first interdigitated finger or the second interdigitated finger; the length direction of the expansion portion is along the length direction of the first interdigitated finger.

[0066] Wherein, λ is twice the shortest distance between the center line of the first interdigitated finger and the center line of the second interdigitated finger.

[0067] Optionally, the length of the protrusion is 0.05 μm to 0.15 μm shorter than the length of the expansion portion, the width of the protrusion is 0.05 μm to 0.15 μm shorter than the width of the expansion portion, and the thickness of the protrusion is 0.01λ to 0.03λ.

[0068] In this embodiment, limiting the width of the protrusion and the width of the expansion portion can prevent the expansion portion from being too small, which could lead to abnormal overlay, deviation of the protrusion from the expansion portion position, and the generation of additional irregularities. Limiting the length of the expansion portion and the protrusion can match and suppress the sound velocity difference range of the transverse mold, thereby better suppressing the transverse mold. Limiting the protrusion thickness, by changing the mass load, can limit the sound velocity difference of the corresponding piezoelectric material layer, thereby better suppressing the transverse mold.

[0069] Secondly, embodiments of this application also provide a method for fabricating a resonator, the method being used to fabricate the resonator described in any of the foregoing embodiments, the method comprising:

[0070] A metal layer is formed by depositing a film on the surface of the piezoelectric material layer.

[0071] An adhesive layer is formed by applying adhesive to the metal layer.

[0072] According to the structure of the transducer, the adhesive layer is exposed and developed;

[0073] The metal layer is etched according to the developed adhesive layer to form the transducer on the surface of the piezoelectric material layer.

[0074] The preparation method in this application embodiment is used to prepare the resonator in any of the above embodiments. Therefore, both methods can solve the same technical problem and achieve the same technical effect.

[0075] Thirdly, embodiments of this application also provide a method for fabricating a resonator, the method being used to fabricate the resonator described in any of the foregoing embodiments, the method comprising:

[0076] An adhesive is applied to the surface of the piezoelectric material layer to form an adhesive layer.

[0077] According to the structure of the transducer, the adhesive layer is exposed and developed;

[0078] The transducer is formed on the surface of the piezoelectric material layer by coating and peeling off the developed adhesive layer.

[0079] The preparation method described in this application is used to prepare the resonator in any of the above embodiments. Therefore, both methods can solve the same technical problem and achieve the same technical effect.

[0080] Fourthly, embodiments of this application also provide a method for fabricating a resonator, the method comprising:

[0081] A first busbar and a second busbar are formed on the surface of the piezoelectric material layer, and the first busbar and the second busbar are spaced apart.

[0082] A first forked finger and a second forked finger are formed on the surface of the piezoelectric material layer, with the first forked finger and the second forked finger being spaced apart.

[0083] A first pseudo-finger is formed on the surface of the piezoelectric material layer;

[0084] Wherein, the first forked finger and the second forked finger are disposed between the first busbar and the second busbar, the first forked finger is connected to the first busbar, and the second forked finger is connected to the second busbar; wherein, the first spur finger corresponds to the first forked finger, the first spur finger is disposed on the side of the second busbar close to the first busbar, the end of the first spur finger away from the second busbar and the end of the first forked finger away from the first busbar are spaced apart in the length direction of the first forked finger, and the end of the first spur finger away from the second busbar and / or the end of the first forked finger away from the first busbar are provided with a first tip;

[0085] Along a direction perpendicular to the surface of the piezoelectric material layer, the first tip forms a first projection on the surface of the piezoelectric material layer; the first side of the first projection pattern corresponding to the first projection gradually decreases or increases in perpendicular distance between the first side and the first busbar on the surface of the piezoelectric material layer; the first side is the side corresponding to the end face of the first tip.

[0086] The preparation method in this application embodiment is used to prepare the resonator in any of the above embodiments and includes the structure of the resonator in any of the above embodiments. Therefore, the two methods can solve the same technical problem and achieve the same technical effect.

[0087] Fifthly, embodiments of this application also provide a filter, including at least one resonator as described above.

[0088] The filters in this application embodiment include the resonators in any of the above embodiments, so both can solve the same technical problem and achieve the same technical effect.

[0089] In a sixth aspect, embodiments of this application also provide a communication chip, including: the filter as described above, and a power amplifier or low-noise amplifier coupled to the filter.

[0090] The communication chip in this application embodiment includes the filter in any of the above embodiments, so both can solve the same technical problem and achieve the same technical effect.

[0091] In a seventh aspect, embodiments of this application also provide an electronic device, including: an antenna and a communication chip as described above, wherein the communication chip is coupled to the antenna.

[0092] Optionally, the communication frequency band of the communication chip includes a low-frequency band.

[0093] In this embodiment, the resonator size in the filter used in the low frequency band is generally large. The resonator in this application embodiment can suppress spurious modes, reduce or eliminate in-band ripple by setting a tip structure at the ends of the interdigitated fingers and / or pseudo-finger, improve the second harmonic of the filter, and realize the miniaturization of the resonator, which is beneficial to the layout of communication chips in electronic devices.

[0094] Optionally, the communication frequency band of the communication chip includes any frequency band within the range of 300MHz to 1000MHz.

[0095] The electronic devices in this application include the communication chip in any of the above embodiments, so both can solve the same technical problem and achieve the same technical effect. Attached Figure Description

[0096] Figure 1 is a diagram showing the relationship between admittance and frequency in the transducer simulation provided in the embodiment of this application as the gap between the interdigital fingers and the pseudofinger changes;

[0097] Figure 2 is a schematic diagram of the structure of the electronic device provided in an embodiment of this application;

[0098] Figure 3 is a schematic diagram of the structure of the communication chip provided in an embodiment of this application;

[0099] Figure 4A is a top view of a transducer without a tip provided in an embodiment of this application;

[0100] Figures 4B to 4D are top views of several transducers with pointed tips provided in the embodiments of this application;

[0101] Figure 4E is a sectional view along the A-A direction in Figures 4A to 4D;

[0102] Figures 5A to 5C are schematic diagrams of several tip projections provided in the embodiments of this application;

[0103] Figure 5D is a schematic diagram of a projection graphic provided in an embodiment of this application;

[0104] Figures 6A to 6C are schematic diagrams of several different tip configurations provided in the embodiments of this application;

[0105] Figure 7A is a simulation diagram of the admittance versus frequency of the transducer provided in the embodiment of this application after the addition of a tip and the increased gap between the interdigital fingers and the pseudo-finger.

[0106] Figure 7B is a simulation diagram of the admittance versus frequency of the transducer provided in the embodiment of this application after setting the tip and increasing the gap between the interdigitated finger and the pseudo-finger;

[0107] Figure 8 is a top view of a transducer with a pointed tip provided in an embodiment of this application;

[0108] Figure 9 is a top view of another transducer with a pointed tip provided in an embodiment of this application;

[0109] Figure 10 is a top view of another transducer with a pointed tip provided in an embodiment of this application;

[0110] Figure 11 is a top view of another transducer with a pointed tip provided in an embodiment of this application;

[0111] Figure 12 is a top view of a transducer with a pointed tip and a protrusion provided in an embodiment of this application;

[0112] Figure 13 is a schematic flowchart of a resonator fabrication method provided in an embodiment of this application;

[0113] Figure 14 is a flowchart illustrating another resonator fabrication method provided in an embodiment of this application.

[0114] Figure reference numerals: 11: Frame; 12: Display panel; 13: Back cover; 14: Motherboard; 15: Antenna; 20: Communication chip; 21: Filter; 22: Power amplifier; 23: Low noise amplifier; 30: Resonator; 31: Piezoelectric material layer; 32: Transducer; 35: Substrate; 321: First busbar; 3211: First auxiliary busbar; 3212: First connecting post; 322: Second busbar; 3221: Second auxiliary busbar; 3222: Second connecting post; 323: Transmission channel; 324: First interdigitated finger; 3241, 3251: First tip; 324 2. 3242: Expansion portion; 3244: First auxiliary pseudo-finger; 3245: Second auxiliary pseudo-finger; 3246, 3247: Protrusion; 325: First pseudo-finger; 3252: First projected pattern; 3253: First side; 3254: First reverse pseudo-finger; 3255: Seventh auxiliary pseudo-finger; 3256: Eighth auxiliary pseudo-finger; 326: Second interdigitated finger; 3261, 3271: Second tip; 3262: Fifth auxiliary pseudo-finger; 3263: Sixth auxiliary pseudo-finger; 327: Second pseudo-finger; 3272: Second reverse pseudo-finger; 3273: Third auxiliary pseudo-finger; 3274: Fourth auxiliary pseudo-finger. Detailed Implementation

[0115] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0116] Hereinafter, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0117] Furthermore, in the embodiments of this application, directional terms such as "up," "down," "left," "right," "horizontal," and "vertical" are defined relative to the orientation of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the orientation of the components in the accompanying drawings.

[0118] In the embodiments of this application, the filter can be a surface acoustic wave (SAW) filter, and correspondingly, the resonator can also be a SAW resonator. The following description uses a SAW resonator as an example. In the embodiments of this application, the gap between the forked and dummy fingers represents the distance between the forked and dummy fingers in the transducer of the resonator along the length direction of the forked finger. The value corresponding to the gap between the forked and dummy fingers is the distance between the forked and dummy fingers along the length direction of the forked finger.

[0119] Research has shown that reducing the second harmonic of the resonator in a filter can improve the overall performance of the filter. In related technologies, substrate asymmetry is the fundamental cause of the second harmonic, with two main mechanisms: 1) self-coupling of the electrostatic field, and 2) coupling of the electrostatic field with the strain field related to the transverse propagation mode. The second harmonic is generated due to the coupling of the electrostatic field and stress field between the interdigital and pseudo-finger gaps. Therefore, theoretically, the second harmonic of the resonator can be reduced by increasing the size of the interdigital and pseudo-finger gaps. However, increasing the size of the interdigital and pseudo-finger gaps makes it difficult to suppress the transverse modes of the resonator. In related technologies, the method for suppressing transverse modes is to suppress higher-order transverse modes in certain frequency bands by using pseudo-fingers of fixed sizes and the gaps between the interdigital and pseudo-finger gaps. When the gaps between the interdigital and pseudo-fingers are increased, the second harmonic is improved, but the suppression structure of the transverse modes changes, generating higher-order transverse modes between the resonant and anti-resonant points, causing ripple in the filter passband and affecting the filter insertion loss.

[0120] For example, when the gap between the interdigitate and spur finger increases from 0.1λ to 0.15λ, the second harmonic distortion improves from -21dB to -37dB, but the transverse mode suppression of the resonator deteriorates. Figure 1 shows the admittance curves of the resonator structure in the related technology when the gap between the interdigitate and spur finger is 0.1λ and 0.15λ, respectively. In Figure 1, the solid lines represent the absolute value and real part of the admittance when the gap between the interdigitate and spur finger is 0.15λ, and the dashed lines represent the absolute value and real part of the admittance when the gap between the interdigitate and spur finger is 0.1λ. The solid and dashed lines located higher in Figure 1 represent the absolute values ​​of the admittance. The solid line representing the absolute value of the admittance when the gap between the interdigitate and spur finger is 0.15λ largely overlaps with the dashed line representing the absolute value of the admittance when the gap between the interdigitate and spur finger is 0.1λ. In Figure 1, the solid and dashed lines at the lower part represent the real portion of the admittance. As can be seen from the figure, when the gap between the interdigital and pseudo-finger increases from 0.1λ to 0.15λ, multiple higher-order transverse-mode clutter are generated near the anti-resonance point (as shown by the dashed circle in Figure 1). Here, λ is the period length of the interdigital electrode in the surface acoustic wave resonator, which can also be specifically defined as twice the shortest distance between the center lines of the first and second interdigital fingers in the embodiments described below.

[0121] To address some problems existing in related technologies, this application provides an electronic device, which may include devices such as mobile phones, tablets, laptops, smart bracelets, and smartwatches. As shown in Figure 2, taking a mobile phone as an example, the electronic device may include a frame 11, a display panel 12, a back cover 13, and a motherboard 14. The frame 11 forms a mounting cavity, the motherboard 14 is disposed within the mounting cavity, the display panel 12 covers one side of the frame 11, and the back cover 13 covers the other side of the frame 11 to close the mounting cavity. The display panel 12 is electrically connected to the motherboard 14 so that the motherboard 14 can control the display panel 12 to display images.

[0122] In the above implementation, the electronic device also includes an antenna 15 and a communication chip 20. The antenna 15 can be disposed on the frame 11 or on the back cover 13, and the communication chip 20 can be disposed on the motherboard 14. The antenna 15 is coupled to the communication chip 20, and the communication chip 20 can feed power to the antenna 15 so that the antenna 15 emits electromagnetic signals; and / or, the antenna 15 receives electromagnetic signals, and the communication chip 20 can receive signals from the antenna 15. With this configuration, wireless communication between the electronic device and base stations, other electronic devices, satellites, etc., can be realized.

[0123] It is understood that the coupling in the embodiments of this application can be understood as direct coupling and / or indirect coupling. Direct coupling can also be called "electrical connection," which can be understood as the physical contact and electrical conduction of components; it can also be understood as the form in which different components in the circuit structure are connected through physical lines that can transmit electrical signals, such as copper foil or wires on a printed circuit board (PCB). "Indirect coupling" can be understood as two conductors conducting electricity through a gap / non-contact method. In one embodiment, indirect coupling can also be called capacitive coupling, for example, signal transmission is achieved by forming an equivalent capacitance through coupling between the gaps between two conductive parts.

[0124] Referring to Figure 3, in some embodiments, the communication chip 20 may include a filter 21. The filter 21 can be coupled to the antenna 15 shown in Figure 2. The filter 21 enables coupling between the communication chip 20 and the antenna 15. At the same time, the filter 21 can remove signals that are not needed for communication, thereby avoiding interference and improving communication quality.

[0125] In some embodiments, the communication chip 20 may include a power amplifier 22. The signal from the signal source passes through the power amplifier 22 and then enters a filter 21. The filter 21 then feeds the signal into the antenna 15 so that the signal can be transmitted outward through the antenna 15. The signal source may include a modulator or other device capable of outputting radio frequency signals. The power amplifier 22 is used to increase the power of the signal to increase the gain of the antenna 15, thereby increasing the transmission distance.

[0126] In some embodiments, the communication chip 20 may further include a low-noise amplifier 23. After the antenna 15 receives electromagnetic signals from the space, it generates an electrical signal. This signal passes through a filter 21 and then enters the low-noise amplifier 23. The signal output by the low-noise amplifier 23 can be transmitted to a demodulator to achieve signal reception. The filter 21 is used to filter out signals outside the communication frequency band, and the low-noise amplifier 23 can improve the signal-to-noise ratio and the accuracy of the received signal.

[0127] In other implementations, the communication chip 20 may also include a power amplifier 22 and a low-noise amplifier 23, which can transmit and receive signals, thereby improving the communication performance of the electronic device.

[0128] In the above implementation, the power amplifier 22, the low-noise amplifier 23 and the filter 21 can be packaged on the same packaging substrate, which can improve the structural compactness of the communication chip 20, and at the same time facilitate the fabrication and installation of the communication chip 20.

[0129] In this embodiment, filter 21 may include multiple resonators, at least two of which are connected in series or in parallel. In one implementation, the cascaded topology of the resonators in filter 21 may include trapezoids, lattices, trapezoid-lattice structures, etc.

[0130] Miniaturization, high isolation, high power tolerance, and low harmonics are all current performance requirements for filters. For example, filter isolation often depends on the filter's number of stages; a higher number of stages results in higher isolation, but also increases insertion loss and filter size. Alternatively, cascading resonators can improve power tolerance and reduce harmonics, but this increases filter size. Therefore, in the various cascaded topologies of filter 21 in this embodiment, the resonators can be partially or entirely adopted from the improved resonators in subsequent embodiments. This can reduce the number of stages in filter 21 to a certain extent, achieving miniaturization while maintaining low harmonics and improving overall performance.

[0131] In one embodiment, the communication frequency band of the communication chip 20 in the electronic device includes a low-frequency band (LB band), the specific range of which can vary depending on different applications and standards. For example, in the field of wireless communication, the LB band typically refers to the 0.3GHz-3GHz range. Accordingly, the filter in this embodiment of the communication chip 20 can be used in the LB band. The resonators in the filters used in the low-frequency band are generally larger. The resonator in this embodiment, by providing a tip structure at the ends of the interdigitated fingers and / or pseudo-finger, can suppress clutter modes, reduce or eliminate in-band ripple, improve the second harmonic of the filter, and achieve miniaturization of the resonator, thereby facilitating the layout of the communication chip in the electronic device.

[0132] In one embodiment, the communication frequency band of the communication chip is any frequency band within the frequency range of 300MHz to 1000MHz, for example, frequency bands B12 (699 to 746MHz), B8 (880 to 960MHz), B26 (814 to 894MHz), B28 (703 to 803MHz), and / or B20 (791 to 862MHz), etc.

[0133] The structure of the resonator will be described in detail below with reference to the accompanying drawings.

[0134] Referring to Figures 4A to 4E, at least one resonator 30 includes a substrate 35, a piezoelectric material layer 31 disposed on the substrate 35, and a transducer 32. The piezoelectric material layer 31 is plate-shaped, and the transducer 32 is disposed on the larger surface area of ​​the piezoelectric material layer 31 (the upper surface shown in Figure 4E). When the transducer 32 receives an electrical signal, it drives the surface of the piezoelectric material layer 31 to vibrate, generating sound waves (e.g., surface acoustic waves). These sound waves propagate along the surface, thereby converting the electrical signal into a mechanical vibration signal (e.g., sound waves). When the sound waves reach the end of the piezoelectric material layer 31, only sound waves that satisfy a specific resonant frequency can be effectively received; sound waves with non-resonant frequencies cancel each other out, thus achieving filtering. It is understood that in this embodiment, the material of the substrate 35 may include silicon, ceramics, etc., and this embodiment does not limit the material of the substrate 35.

[0135] This application does not limit the material of the piezoelectric material layer 31, as long as it ensures that the piezoelectric material layer 31 can vibrate under the drive of the transducer 32 to generate sound waves. For example, the material of the piezoelectric material layer 31 may include lithium niobate (LiNbO3), lithium tantalate (LiTaO3), quartz, aluminum nitride (AlN), scandium-doped aluminum nitride (AlScN), lead metaniobate (PbNb2O6), lead zirconate titanate (PZT), and other piezoelectric materials. It is understood that in some implementations, the piezoelectric material layer 31 may also include multiple stacked film layers, each of which may include any of the above-mentioned piezoelectric layer materials. By including multiple stacked film layers in the piezoelectric material layer 31, energy scattering and absorption in the piezoelectric material layer 31 can be reduced, thereby improving the quality factor (Q value) of the resonator 30.

[0136] Referring again to Figures 4A-4E, in some embodiments, the transducer 32 drives the piezoelectric material layer 31 to vibrate under the action of an electrical signal. For example, the transducer 32 may include an interdigital transducer (IDT). The transducer 32 includes a first busbar 321 and a second busbar 322 spaced apart on the surface of the piezoelectric material layer 31. For example, the first busbar 321 and the second busbar 322 extend on the piezoelectric material layer 31, and their extension directions (length direction, the horizontal direction in Figures 4A-4D) are parallel. The first busbar 321 and the second busbar 322 are spaced apart along their width direction. The width direction is a direction parallel to the piezoelectric material layer 31 and perpendicular to the extension directions of the first busbar 321 and the second busbar 322 (the vertical direction in Figures 4A-4D). A transmission channel 323 is formed between the first busbar 321 and the second busbar 322, allowing acoustic waves to propagate near the surface of the piezoelectric material layer 31 corresponding to this transmission channel 323. It is understood that this transmission channel 323 can be the region between the overlapping portions of the first busbar 321 and the second busbar 322 in the vertical direction shown in Figures 4A to 4D.

[0137] The transducer 32 also includes a first forked finger 324 and a second forked finger 326, which are spaced apart between the first busbar 321 and the second busbar 322. The first forked finger 324 is connected to the first busbar 321, and the second forked finger 324 is connected to the second busbar 322.

[0138] Specifically, the first forked finger 324 and the second forked finger 326 are disposed on the surface of the piezoelectric material layer 31, and the first forked finger 324 and the second forked finger 326 are located within the transmission channel 323, that is, the first forked finger 324 and the second forked finger 326 are located between the first busbar 321 and the second busbar 322. The first forked finger 324 and the second forked finger 326 extend on the piezoelectric material layer 31, and their extension directions (length directions) are parallel. The first forked finger 324 and the second forked finger 326 are spaced apart along their width direction, which is perpendicular to the extension direction of the first forked finger 324 and the second forked finger 326. The extension direction of the first forked finger 324 may be perpendicular to the extension direction of the first busbar 321, or there may be other angles between the extension direction of the first forked finger 324 and the extension direction of the first busbar 321. The first forked finger 324 is connected to the first busbar 321 at one end, and is spaced apart from the second busbar 322 at one end. Similarly, the extension direction of the second forked finger 326 may be perpendicular to the extension direction of the second busbar 322, or there may be other angles between the extension direction of the second forked finger 326 and the extension direction of the second busbar 322. The second forked finger 326 is connected to the second busbar 322 at one end, and is spaced apart from the first busbar 321 at one end.

[0139] The first busbar 321 and the second busbar 322 are used to receive radio frequency signals. The first busbar 321 feeds the radio frequency signal into the first interdigital finger 324, and the second busbar 322 feeds the radio frequency signal into the second interdigital finger 326, so that the piezoelectric material layer 31 near the first interdigital finger 324 and the second interdigital finger 326 vibrates, thereby forming sound waves.

[0140] In some embodiments, there are multiple first interdigitated fingers 324 and multiple second interdigitated fingers 326. These multiple first interdigitated fingers 324 and multiple second interdigitated fingers 326 are alternately arranged along the extension direction of the first busbar 321. That is, a second interdigitated finger 326 is arranged between two adjacent first interdigitated fingers 324, and a first interdigitated finger 324 is arranged between two connected second interdigitated fingers 326. Thus, the first busbar 321 can simultaneously feed power to each first interdigitated finger 324, and the second busbar 322 can simultaneously feed power to each second interdigitated finger 326. The piezoelectric material layer 31 near each first interdigitated finger 324 and second interdigitated finger 326 can vibrate to generate sound waves, thereby increasing the power of the resonator 30.

[0141] In some embodiments, the first interdigitated finger 324 can be integrally formed with the first busbar 321. Correspondingly, the first interdigitated finger 324 and the first busbar 321 can be formed by methods such as vapor deposition or electroplating. Taking vapor deposition as an example, during fabrication, a metal layer can first be formed on the piezoelectric material layer 31 by vapor deposition, and then some of the metal can be removed by etching to form the first interdigitated finger 324 and the first busbar 321. Similarly, the second busbar 322 and the second interdigitated finger 326 can also be integrally formed. The preparation methods of the second busbar 322 and the second interdigitated finger 326 can be roughly similar to the preparation methods of the first interdigitated finger 324 and the first busbar 321, and will not be described in detail here.

[0142] In some embodiments, the first interdigitated finger 324, the first busbar 321, the second interdigitated finger 326, and the second busbar 322 can be formed simultaneously using the same manufacturing method to reduce the manufacturing difficulty of the resonator 30 and save manufacturing costs; on the other hand, it can also improve the manufacturing efficiency of the resonator 30.

[0143] In some embodiments, as shown in Figures 4A to 4E, the cross section of the first interdigitated finger 324 and the second interdigitated finger 326 along AA can be rectangular or trapezoidal, and this application does not impose any specific limitations.

[0144] In some embodiments, the transducer 32 further includes a first pseudo-finger 325, which corresponds to a first interdigitated finger 324. The first pseudo-finger 325 is disposed on the side of the second busbar 322 near the first busbar 321. The end of the first pseudo-finger 325 away from the second busbar 322 and the end of the first interdigitated finger 324 away from the first busbar 321 are spaced apart along the length of the first interdigitated finger 324. As shown in Figures 4A to 4D, the length direction of the first interdigitated finger 324 is parallel to the piezoelectric material layer 31 and perpendicular to the extension direction of the first busbar 321 or the second busbar 322.

[0145] In a specific embodiment, the first dummy finger 325 is disposed on the piezoelectric material layer 31, and is positioned between the second busbar 322 and the first busbar 321. In some embodiments, the first dummy finger 325 is connected to the second busbar 322. In some embodiments, the first dummy finger 325 may also be spaced apart from the second busbar 322. This arrangement can reduce the sound velocity of the portion of the piezoelectric material layer 31 corresponding to the first dummy finger 325, causing the sound waves on the piezoelectric material layer 31 corresponding to the transmission channel 323 to be reflected at the location of the first dummy finger 325, thus preventing sound waves from leaking out of the first busbar 321.

[0146] In some embodiments, the correspondence between the first pseudo-finger 325 and the first interdigitated finger 324 means that, along the extension direction perpendicular to the first busbar 321, the projections of the first pseudo-finger 325 and the first interdigitated finger 324 on the first busbar 321 can at least partially overlap. Furthermore, the projections of the first pseudo-finger 325 and the first interdigitated finger 324 on the first busbar 321 completely overlap.

[0147] In some embodiments, the electrode materials of the first interdigital finger 324, the second interdigital finger 326, the first pseudo-finger 325, and those involved in subsequent embodiments may include one or more materials with a density greater than 8900 kg / m³. 3 Heavy electrode materials, such as platinum (Pt), molybdenum (Mo), tungsten (W), aluminum (Al), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), copper (Cu), tantalum (Ta), osmium (Os), iridium (Ir), and gold (Au), etc. Optionally, multiple metal layers may be stacked on the piezoelectric material layer 31. Adjacent metal layers may be of different materials. Since different metals have different densities, the overall density of the interdigitated fingers can be adjusted by appropriately selecting the materials of each metal layer. In some examples, both the first interdigitated finger 324 and the second interdigitated finger 326 include at least two metal layers. One metal layer may be made of aluminum, and the other metal layer may be made of platinum, molybdenum, or tungsten to ensure that the first interdigitated finger 324 and the second interdigitated finger 326 have a higher density. In some examples, one metal layer may be made of copper, and the other metal layer may be made of platinum, gold, molybdenum, or tungsten.

[0148] It is understandable that the resonator 30 satisfies f = v / (2λ), where f is the resonant frequency of the sound wave generated by the resonator 30, v is the propagation speed of the sound wave near the surface of the piezoelectric material layer 31 (sound speed), and λ is the wavelength of the sound wave. When the resonant frequency is constant, reducing the sound speed can reduce the wavelength of the sound. In the transducer 32, twice the shortest distance L1 between the center lines of the first interdigitate 324 and the second interdigitate 326 is equal to the wavelength. Furthermore, increasing the density of the first interdigitate 324 and the second interdigitate 326 can reduce the sound speed on the surface of the piezoelectric material layer 31. Therefore, by increasing the density of the first interdigitate 324 and the second interdigitate 326, the wavelength of the sound wave can be reduced, thereby reducing the distance between the first interdigitate 324 and the second interdigitate 326, which can reduce the volume of the transducer 32 and the resonator 30, facilitating miniaturization. For example, the density of the first interdigitate 324 and the second interdigitate 326 can be greater than or equal to 8900 kg / m³. 3 .

[0149] It should be noted that, in the embodiments of this application, the center line of the first forked finger 324 or the center line of the second forked finger 326 refers to a virtual line segment that divides the width of the first forked finger 324 or the second forked finger 326 equally along its length in a direction parallel to the piezoelectric material layer 31, as exemplarily shown by the dashed lines in Figures 4A to 4D.

[0150] Referring again to Figures 1 and 4A, in this embodiment, when the resonator 30 is working, it generates sound waves through the transducer 32. These sound waves can generate a first resonance (Rayleigh mode) and a second resonance (Shear Horizontal, abbreviated as SH mode) as shown in Figure 1. The resonant frequency of the first resonance is not equal to the resonant frequency of the second resonance. The sound waves corresponding to the first resonance and the second resonance propagate near the surface of the piezoelectric material layer 31 corresponding to the transmission channel 323, along a direction that is approximately parallel to the length of the first busbar 321.

[0151] In some examples, the second resonance includes a resonant point and an anti-resonant point. In the aforementioned related techniques, the transverse mode suppression method is to suppress higher-order transverse modes corresponding to the frequency band of the second resonance by using a fixed-size first dummy finger and the gap between the interdigitated fingers. However, when the gap between the interdigitated fingers and the dummy fingers increases (for example, the spacing between the first dummy finger 325 and the first interdigitated finger 324 increases from 0.1λ to 0.15λ), the transverse mode suppression structure changes, and higher-order transverse modes are generated near the anti-resonant point of the second resonance (as shown by the dashed circle in Figure 1), causing ripple in the filter passband and affecting the filter insertion loss.

[0152] Referring again to Figures 4B to 4D, in this embodiment, the first pseudo-finger 325 has a first tip at one end away from the second busbar 322 and / or the first interdigitated finger 324 has a first tip at one end away from the first busbar 321. Along a direction perpendicular to the surface of the piezoelectric material layer 31, the first tip forms a first projection on the surface of the piezoelectric material layer 31; the vertical distance between the first side of the first projection pattern corresponding to the first projection and the first busbar 321 on the surface of the piezoelectric material layer 31 gradually decreases or increases along the first side; wherein, the first side is the side corresponding to the end face of the first tip.

[0153] In some embodiments, the first tip is integrally formed with the first pseudo-finger 325 or the first interdigital finger 324, or the first pseudo-finger 325 is connected to the first tip by welding or other means. That is, the first tip may be part of the first pseudo-finger 325 or the first interdigital finger 324. The first tip and the first pseudo-finger 325 or the first interdigital finger 324 are divided by dashed lines in the accompanying drawings for ease of description, but this does not mean that they necessarily belong to two parts, and is not intended to limit the scope of this application. Based on this, the end face of the first tip can also be understood as the end face of the first pseudo-finger 325 or the first interdigital finger 324 that is close to each other.

[0154] In this embodiment, to satisfy the requirement that the vertical distance between the first side of the first projected pattern and the first busbar 321 on the surface of the piezoelectric material layer 31 gradually decreases or increases along the first side, the end face of the first tip must at least satisfy the following conditions: it is not perpendicular to the length direction of the first pseudo-finger 325 or the first interdigitated finger 324, and it is not parallel to the width direction of the first pseudo-finger 325 or the first interdigitated finger 324. As one implementation, the end face of the first tip is perpendicular to the surface of the piezoelectric material layer 31, but not perpendicular to the length direction of the first pseudo-finger 325 or the first interdigitated finger 324. However, due to errors in the manufacturing process of the pseudo-finger and interdigitated finger, the end face of the first tip may not be completely perpendicular to the surface of the piezoelectric material layer 31, and the end face of the first tip may not be a standard plane; it may have some small irregularities or angles.

[0155] The following example illustrates the case of the first tip of the first pseudo-finger 325 and / or the first interdigital finger 324.

[0156] Referring again to FIG4B, in one embodiment, the end of the first dummy finger 325 away from the second busbar 322 includes a first tip 3251, and the first forked finger 324 does not include the first tip 3241. The end face of the first forked finger 324 is not inclined, that is, the end face of the first forked finger 324 near the end of the first dummy finger 325 is perpendicular to the length direction of the first dummy finger 325 or the first forked finger 324 and parallel to the width direction of the first dummy finger 325 or the first forked finger 324.

[0157] For example, as shown in Figures 5A and 5D, the arrows in the figures point in the length direction of the first pseudo-finger 325, pointing towards the first busbar 321, and in the opposite direction towards the second busbar 322. Dashed lines are used in the figures to schematically distinguish the first tip 3251 of the first pseudo-finger 325. In the figures, the first projection pattern 3252 is formed by the outer contour of the first projection of the first tip 3251 along a direction perpendicular to the surface of the piezoelectric material layer 31, and the edge corresponding to the end face is the first edge 3253. The end face of the first tip 3251 is perpendicular to the surface of the piezoelectric material layer 31 and forms a certain angle with the length direction of the first pseudo-finger 325 or the first interdigitated finger 324, such that the first edge 3253 forms an acute angle α with the length direction of the first pseudo-finger 325 (the direction of the arrow in Figure 5A) on the plane containing the first projection pattern 3252.

[0158] For example, as shown in Figures 5B and 5D, the arrows in the figures point along the length of the first pseudo-finger 325, with the arrows pointing towards the first busbar 321 and the opposite direction pointing towards the second busbar 322. Dashed lines are used in the figures to schematically distinguish the first tip 3251 of the first pseudo-finger 325. The end face of the first tip 3251 is no longer perpendicular to the surface of the piezoelectric material layer 31; instead, the bottom edge of the end face of the first tip 3251 is offset in the opposite direction of the arrow, forming an acute angle θ between the end face of the first tip 3251 and the direction perpendicular to the surface of the piezoelectric material layer 31. However, since the upper surface of the first tip 3251 is the same as in Figure 5A, the first projection pattern 3252 of the plane formed by the outer contour of the first projection of the first tip 3251 along the direction perpendicular to the surface of the piezoelectric material layer 31 remains the same as in Figure 5A. The offset of the bottom edge of the end face of the first tip 3251 in the opposite direction of the arrow may be due to process error or performance requirement improvement. Therefore, the value of θ may be less than 10° or even less than 5°.

[0159] For example, as shown in Figures 5C and 5D, the arrows in the figures point along the length of the first pseudo-finger 325, with the arrows pointing towards the first busbar 321 and the opposite direction pointing towards the second busbar 322. Dashed lines are used in the figures to schematically distinguish the first tip 3251 of the first pseudo-finger 325. The end face of the first tip 3251 is no longer perpendicular to the surface of the piezoelectric material layer 31; instead, the top edge of the end face of the first tip 3251 is offset in the opposite direction of the arrow, forming an acute angle θ between the end face of the first tip 3251 and the direction perpendicular to the surface of the piezoelectric material layer 31. However, since the lower surface of the first tip 3251 is the same as in Figure 5A, the first projection pattern 3252 of the plane formed by the outer contour of the first projection of the first tip 3251 along the direction perpendicular to the surface of the piezoelectric material layer 31 remains the same as in Figure 5A. The offset of the top edge of the end face of the first tip 3251 in the opposite direction of the arrow may be due to process error or performance requirement improvement. Therefore, the value of θ may be less than 10° or even less than 5°.

[0160] As shown in Figure 5D, which is a first projected shape 3252 in this embodiment, since the tip of the first tip 3251 can be a similar chamfer in actual manufacturing, the corresponding part of the first projected shape 3252 in Figure 5D can also be a similar chamfer, making the first projected shape 3252 a triangle-like shape, with its first side 3253 being a hypotenuse similar to that of a triangle. It should be noted that when the tip of the first tip 3251 is a similar chamfer, the first side 3253 can be counted from the position excluding the chamfer, thus clearly defining the start and end points of the first side 3253.

[0161] It should be noted that the end face of the first tip 3251 shown in Figures 5A to 5D is a flat plane with straight edges. However, in actual products, the end face may have roughness, and the edges may be relatively blurred. Therefore, the edges of the first projected pattern 3252 may not be very clear. In this case, the first projected pattern 3252 can be accurately defined by line segment fitting. Therefore, the figures in this application are only schematic and are not intended to limit the details. Uneven end faces and relatively blurred edges are all within the scope of protection of this application. In addition, the tilting trend of the end face of the first tip 3251 can be downward tilting from left to right as shown in Figure 4D, or downward tilting from right to left as shown in the figure. Therefore, in this application, it can be summarized that the vertical distance between the first side 3253 on the surface of the piezoelectric material layer 31 and the first busbar 321 gradually decreases or increases along the first side 3253.

[0162] Referring to FIG4C, in one embodiment, the end of the first interdigitated finger 324 away from the first busbar 321 includes a first tip 3241. The first pseudo-finger 325 does not include the first tip 3251, and the end face of the first pseudo-finger 325 is not inclined, that is, the end face of the first pseudo-finger 325 near the first interdigitated finger 324 is perpendicular to the length direction of the first pseudo-finger 325 or the first interdigitated finger 324, and parallel to the width direction of the first pseudo-finger 325 or the first interdigitated finger 324.

[0163] The implementation of the first tip 3241 in this embodiment and its projection can be seen with reference to Figures 5A to 5D, and will not be described again.

[0164] Referring again to FIG4D, in some embodiments, the end of the first pseudofinger 325 away from the second busbar 322 includes a first tip 3251, and the end of the first interdigital finger 324 away from the first busbar 321 includes a first tip 2141.

[0165] The implementation of the first tip 3241 and the first tip 3251 in this embodiment, as well as their projection, can be seen with reference to Figures 5A to 5D, and will not be described again.

[0166] Next, referring to Figures 6A to 6C, examples will be given to illustrate the gap between the interdigitated finger and the prosthetic finger involved in the aforementioned embodiments.

[0167] As shown in Figure 6A, the first prosthetic finger 325 includes the first tip 3251, and the first interdigital finger 324 does not include the first tip 3241. The gap between the interdigital finger and the prosthetic finger is the shortest distance from the end face of the first interdigital finger 324 to the first tip 3251 in the length direction of the first interdigital finger 324 and / or the first prosthetic finger 325.

[0168] As shown in Figure 6B, the first pseudofinger 325 does not include the first tip 3251, and the first forked finger 324 includes the first tip 3241. The gap between the forked finger and the pseudofinger is the shortest distance from the end face of the first pseudofinger 325 to the first tip 3241 in the length direction of the first forked finger 324 and / or the first pseudofinger 325.

[0169] As shown in Figure 6C, the first prosthetic finger 325 includes a first tip 3251, the first interdigital finger 324 includes a first tip 3241, and the two end faces are parallel. The gap (Gap) value between the interdigital finger and the prosthetic finger is the minimum distance between the two end faces in the length direction of the first interdigital finger 324 and / or the first prosthetic finger 325.

[0170] It should be noted that, as shown in Figures 4A to 4D, the broken lines in the dashed box S on the left represent the sound velocities of the piezoelectric material layer 31 at different positions of the transducer 32. The closer the line segment of the broken line is to the transducer 32, the lower the sound velocity of the piezoelectric material layer 31 at that position.

[0171] For example, as shown in Figures 4A and 4B, compared to Figure 4A where no tip is formed, in Figure 4B, after the first tip 3251 is formed on the first prosthetic finger 325, a transition region is formed between the sound velocity of the piezoelectric material layer 31 in the region where the first prosthetic finger 325 is located and the sound velocity of the piezoelectric material layer 31 in the gap region between the interdigital finger and the prosthetic finger. This reduces the effective distance between the high and low sound velocity regions in the gap region between the interdigital finger and the prosthetic finger, thereby better suppressing transverse modes.

[0172] Therefore, in the aforementioned embodiments, by changing the end face shape of the first interdigital finger 324 and / or the first pseudo-finger 325, the magnitude of the electrostatic field in the stress field direction (i.e., the length direction of the first pseudo-finger 325) remains unchanged without altering the spacing value corresponding to the gap between the interdigital finger and the pseudo-finger, thus preventing the deterioration of the second harmonic. However, changing the end face shape of the first interdigital finger 324 and / or the first pseudo-finger 325 can alter the tip mass load, reducing the effective distance between the high and low sound velocity regions in the gap between the interdigital finger and the pseudo-finger, thereby better suppressing transverse modes.

[0173] Please refer to Figures 7A and 7B. Figure 7A shows the admittance versus frequency of the transducer without a tip and with an increased gap between the interdigitate and pseudofinger. Figure 7B shows the admittance versus frequency of the transducer with at least a first tip and with an increased gap between the interdigitate and pseudofinger. In the figures, solid lines represent the absolute value of the admittance, and dashed lines represent the real part of the admittance. Comparing Figures 7A and 7B, it can be seen that although the gap between the interdigitate and pseudofinger increases, after adding the first tip, the dashed line near the anti-resonance point of the second resonance becomes flatter (as shown in the dashed box area in Figure 7B), and the transverse wave is still suppressed.

[0174] In one embodiment, when both the first prosthetic finger 325 and the first interdigital finger 324 are provided with a first tip, the changing trend of the vertical distance between the first edge formed by the first tip of the first prosthetic finger 325 and the first busbar 321 is the same as the changing trend of the vertical distance between the first edge formed by the first tip of the first interdigital finger 324 and the first busbar 321.

[0175] For example, as shown in Figure 4D, the first tip of the first pseudo-finger 325 is the first tip 3251 in the figure, and the first tip of the first interdigitated finger 324 is the first tip 3241 in the figure. The changing trend of the vertical distance between the first edge formed by the first tip of the first pseudo-finger 325 and the first busbar 321 is the same as the changing trend of the vertical distance between the first edge formed by the first tip of the first interdigitated finger 324 and the first busbar 321. This can be expressed as follows: the tilting trend of the end face of the first tip 3251 is the same as the tilting trend of the end face of the first tip 3241. For example, the tilting trends of the end faces of both the first tip 3251 and the first tip 3241 are both gradually tilting downwards from left to right in Figure 4D, or the tilting trends of the end faces of both the first tip 3251 and the first tip 3241 are both gradually tilting downwards from right to left in Figure 4D.

[0176] In one embodiment, the tilting trend of the end face of the first tip 3251 may be opposite to that of the end face of the first tip 3241. For example, the tilting trend of the end face of the first tip 3251 gradually tilts downward in the direction from left to right in FIG. 4D, and the tilting trend of the end face of the first tip 3241 gradually tilts downward in the direction from right to left in FIG. 4D.

[0177] In one embodiment, when the tilting trend of the end face of the first tip 3251 is the same as the tilting trend of the end face of the first tip 3241, the tilting slope of the first side corresponding to the end face of the first tip 3251 is also the same as that of the first side corresponding to the end face of the first tip 3241.

[0178] In some embodiments, 40°≤α≤85°. A tip angle less than 40° may generate tip discharge, while an angle greater than 85° results in an overly gentle tip inclination, limiting its effect on changing the tip mass load. Therefore, the acute angle α can be limited to 40°≤α≤85°. In one embodiment, to achieve a better effect on changing the tip mass load, the acute angle α can be further limited to 55°≤α≤75°. In another embodiment, the acute angle α can be further limited to 60°≤α≤65°, for example, values ​​of 62° or 63°. It should be noted that certain process tolerances are allowed for the acute angle α, for example, tolerances of ±5° or ±3°.

[0179] The dimensions of the resonator structure described in the foregoing embodiments will now be explained.

[0180] In the aforementioned embodiments, only the end shape of the first pseudo-finger 325 or the first interdigital finger 324 was improved and defined. In this embodiment, the gap between the interdigital finger and the pseudo-finger is specifically defined, which can improve the second harmonic of the resonator. Specifically:

[0181] The minimum distance between the end of the first pseudo-finger 325 away from the second busbar 322 and the end of the first interdigitated finger 324 away from the first busbar 321 along the length direction of the first interdigitated finger 324 or the first pseudo-finger 325 is 0.15λ to 0.25λ; where λ is twice the shortest distance between the center line of the first interdigitated finger 324 and the center line of the second interdigitated finger 326, which is the period length of the interdigitated finger electrode.

[0182] Specifically, when the first pseudo-finger 325 has a first tip 3251 at the end away from the second busbar 322, the minimum distance between the first tip 3251 and the first interdigitated finger 324 in the length direction of the first interdigitated finger 324 or the first pseudo-finger 325 is 0.15λ to 0.25λ; when the first interdigitated finger 324 has a first tip 3241 at the end away from the first busbar 321, the minimum distance between the first tip 3241 and the first pseudo-finger 325 in the length direction of the first interdigitated finger 324 or the first pseudo-finger 325 is 0.15λ to 0.25λ; when both the first pseudo-finger 325 at the end away from the second busbar 322 and the first interdigitated finger 324 at the end away from the first busbar 321 have first tips, the minimum distance between the two first tips in the length direction of the first interdigitated finger 324 or the first pseudo-finger 325 is 0.15λ to 0.25λ.

[0183] For example, as shown in Figures 6A to 6C, the minimum distance between the end of the first dummy finger 325 away from the second busbar 322 and the end of the first forked finger 324 away from the first busbar 321 along the length of the first forked finger 324 or the first dummy finger 325 is the value of the gap between the forked finger and the dummy finger along the length of the first forked finger 324 or the first dummy finger 325. Therefore, in this embodiment, the value of the gap between the forked finger and the dummy finger along the length of the first forked finger 324 or the first dummy finger 325 is in the range of 0.15λ to 0.25λ. This value range can reduce the second harmonic of the resonator.

[0184] In some embodiments, in the first projected pattern 3252, the distance difference between the point on the first side 3253 furthest from the first busbar 321 and the point on the first side 3253 closest to the first busbar 321 in the length direction of the first interdigitated finger 324 is 0.1λ to 0.25λ. The point on the first side 3253 furthest from the first busbar 321 and the point on the first side 3253 closest to the first busbar 321 can be determined according to the aforementioned method for determining the start and end points of the first side 3253, which will not be repeated here.

[0185] Along the length direction parallel to the piezoelectric material layer 31 and parallel to the first busbar 321, the width of the first pseudo-finger 325 is 0.2λ to 0.3λ. It can be understood that, including the first tip 3241, the dimension of the first tip 3241 along the width direction of the first pseudo-finger 325 is also 0.2λ to 0.3λ, meaning that the dimension of the first tip 3241 along the width direction of the first pseudo-finger 325 can also represent the width of the first pseudo-finger 325.

[0186] Along the length direction of the first pseudofinger 325, the minimum distance between the end face of the first tip 3251 of the first pseudofinger 325 and the end of the first pseudofinger 325 near the second busbar 322 is 0.15λ to 0.25λ.

[0187] For example, as shown in Figure 6A, b represents the distance difference between the point farthest from the first busbar 321 on the first side 3253 and the point closest to the first busbar 321 on the first side in the first projected pattern 3252, along the length direction of the first interdigitated finger 324. a represents the width of the first dummy finger 325 along the length direction parallel to the piezoelectric material layer 31 and parallel to the first busbar 321. L2 represents the minimum distance from the end face of the first tip 3251 of the first dummy finger 325 to the end of the first dummy finger 325 near the second busbar 322 along the length direction of the first dummy finger 325.

[0188] Referring again to Figures 4A to 4D, in some embodiments, the transducer 32 further includes a second pseudo-finger 327, which corresponds to the second interdigitated finger 326. The second pseudo-finger 327 is disposed on the side of the first busbar 321 near the second busbar 322. The end of the second pseudo-finger 327 away from the first busbar 321 is spaced apart from the end of the second interdigitated finger 326 away from the second busbar 322.

[0189] Furthermore, the second pseudo-finger 327 is provided with a second tip at the end away from the first busbar 321 and / or the second interdigitated finger 326 is provided with a second tip at the end away from the second busbar 326; along the direction perpendicular to the surface of the piezoelectric material layer 31, the second tip forms a second projection on the surface of the piezoelectric material layer 31; the second side of the second projection pattern corresponding to the second projection gradually decreases or increases in vertical distance from the second busbar 322 on the surface of the piezoelectric material layer 31 along the second side; wherein, the second side is the side corresponding to the end face of the second tip.

[0190] In other words, the second pseudo-finger 327 is disposed on the piezoelectric material layer 31. The second pseudo-finger 327 can be disposed between the second interdigitated finger 326 and the first busbar 321, and the second pseudo-finger 331 is spaced apart from the second interdigitated finger 326. In some embodiments, the second pseudo-finger 327 is connected to the first busbar 321. In some embodiments, the second pseudo-finger 327 can also be spaced apart from the first busbar 321. This arrangement can reduce the sound velocity of the portion of the piezoelectric material layer 31 corresponding to the second pseudo-finger 327, causing the sound waves on the piezoelectric material layer 31 corresponding to the transmission channel 323 to be reflected at the location of the second pseudo-finger 327, preventing the sound waves from leaking out of the first busbar 321. In some examples, the correspondence between the second pseudo-finger 327 and the second interdigitated finger 326 means that, along the length direction perpendicular to the first busbar 321, the projections of the second pseudo-finger 327 and the second interdigitated finger 326 on the first busbar 321 can at least partially overlap, and further, the projections of the second pseudo-finger 327 and the second interdigitated finger 326 on the first busbar 321 completely overlap.

[0191] In some embodiments, the second tip is integrally formed with the second pseudo-finger 327 or the second interdigitated finger 326, or the second pseudo-finger 327 is connected to the second tip by welding or other means. That is, the second tip may be part of the second pseudo-finger 327 or the second interdigitated finger 326. The second tip and the second pseudo-finger 327 or the second interdigitated finger 326 are divided by dashed lines in the accompanying drawings for ease of description, but this does not mean that they necessarily belong to two parts, and is not intended to limit the scope of this application. Based on this, the end face of the second tip can also be understood as the end face of the second pseudo-finger 327 or the second interdigitated finger 326 that is close to each other.

[0192] In this embodiment, to satisfy the requirement that the vertical distance between the second side of the second projected pattern and the second busbar 322 on the surface of the piezoelectric material layer 31 gradually decreases or increases along the second side, the end face of the second tip must at least satisfy the following conditions: it is not perpendicular to the length direction of the second pseudo-finger 327 or the second interdigitated finger 326, and it is not parallel to the width direction of the second pseudo-finger 327 or the second interdigitated finger 326. As one implementation, the end face of the second tip is perpendicular to the surface of the piezoelectric material layer 31, but not perpendicular to the length direction of the second pseudo-finger 327 or the second interdigitated finger 326. However, due to errors in the manufacturing process of the pseudo-finger and interdigitated finger, the end face of the second tip may not be completely perpendicular to the surface of the piezoelectric material layer 31, and the end face of the second tip may not be a standard plane; it may have some small irregularities or inclinations.

[0193] Therefore, several embodiments of the second tip of the second pseudofinger 327 and / or the second interdigital finger 326 include: the end of the second pseudofinger 327 away from the first busbar 321 includes a second tip 3271; the end of the second interdigital finger 326 away from the second busbar 322 includes a second tip 3261. The second pseudofinger 327 includes a second tip 3271 at the end away from the first busbar 321, and the second interdigital finger 326 includes a second tip 3261 at the end away from the second busbar 322.

[0194] Examples of projections corresponding to several implementations of the second tips of the second pseudo-finger 327 and / or the second interdigital finger 326 can be found in Figures 5A and 5D, showing the first tips of the first pseudo-finger 325 and / or the first interdigital finger 324, which will not be repeated here. In the second projection pattern formed by their projections, the second side forms an acute angle β with the length direction of the second pseudo-finger 327 and / or the second interdigital finger 326.

[0195] Furthermore, the example of the gap between the interdigitated finger and the prosthetic finger involved in this embodiment can also be referred to the implementation methods corresponding to Figures 6A to 6C.

[0196] It should be noted that, as shown in Figures 4A to 4D, the broken lines in the dashed box S on the left represent the sound velocities of the piezoelectric material layer 31 at different positions of the transducer 32. The closer the line segment of the broken line is to the transducer 32, the lower the sound velocity of the piezoelectric material layer 31 at that position.

[0197] For example, as shown in Figures 4A and 4B, compared to Figure 4A where no tip is formed, Figure 4B not only forms a transition region between the sound velocity of the piezoelectric material layer 31 in the region where the first pseudofinger 325 is located and the sound velocity of the piezoelectric material layer 31 in the gap region between the interdigitated finger and the pseudofinger after the first tip 3251 is formed in the first pseudofinger 325, but also forms a transition region between the sound velocity of the piezoelectric material layer 31 in the region where the second pseudofinger 327 is located and the sound velocity of the piezoelectric material layer 31 in the gap region between the interdigitated finger and the pseudofinger after the second tip 3271 is formed in the second pseudofinger 327. This reduces the effective distance between the high and low sound velocity regions in the gap region between the interdigitated finger and the pseudofinger, thereby better suppressing transverse modes.

[0198] In one embodiment, when both the second pseudofinger 327 and the second interdigital finger 326 are provided with a second tip, the changing trend of the distance between the second side formed by the second tip 3271 of the second pseudofinger 327 and the second busbar 322 is the same as the changing trend of the distance between the second side formed by the second tip 3261 of the second interdigital finger 326 and the second busbar 322.

[0199] For example, as shown in Figure 4D, the second tip of the second pseudo-finger 327 is the second tip 3271 in the figure, and the second tip of the second interdigitated finger 326 is the second tip 3261 in the figure. The changing trend of the vertical distance between the second side formed by the second tip 3271 of the second pseudo-finger 327 and the second busbar 322 is the same as the changing trend of the vertical distance between the second side formed by the second tip 3261 of the second interdigitated finger and the second busbar 322. This can be expressed as follows: the tilting trend of the end face of the second tip 3271 is the same as the tilting trend of the end face of the second tip 3261. For example, the tilting trends of the end faces of the second tip 3271 and the second tip 3261 are both gradually tilted downwards from left to right in Figure 4D, or the tilting trends of the end faces of the second tip 3271 and the second tip 3261 are both gradually tilted downwards from right to left in Figure 4D.

[0200] In one embodiment, the tilting trend of the end face of the second tip 3271 may be opposite to that of the end face of the second tip 3261. For example, the tilting trend of the end face of the second tip 3271 gradually tilts downward in the direction from left to right in FIG. 4D, and the tilting trend of the end face of the second tip 3261 gradually tilts downward in the direction from right to left in FIG. 4D.

[0201] In one embodiment, when the tilting trend of the end face of the second tip 3271 is the same as that of the end face of the second tip 3261, the tilting slope of the second side corresponding to the end face of the second tip 3271 is also the same as that of the second side corresponding to the end face of the second tip 3261.

[0202] In some embodiments, 40°≤β≤85°. A tip angle less than 40° may generate tip discharge, while an angle greater than 85° results in an overly gentle tip inclination, limiting its effect on changing the tip mass load. Therefore, the acute angle β can be limited to 40°≤β≤85°. In one embodiment, to achieve a better effect on changing the tip mass load, the acute angle β can be further limited to 55°≤β≤75°. In another embodiment, the acute angle β can be further limited to 60°≤β≤65°, for example, values ​​of 62° or 63°. It should be noted that certain process tolerances are allowed for the acute angle β, for example, tolerances of ±5° or ±3°.

[0203] The dimensions of the resonator structure described in the foregoing embodiments will be explained next.

[0204] In the aforementioned embodiments, only the end shape of the second pseudo-finger 326 or the second interdigital finger 326 was improved and defined. In this embodiment, the gap between the interdigital finger and the pseudo-finger is specifically defined, which can further improve the second harmonic of the resonator. Specifically:

[0205] The minimum distance between the end of the second pseudo-finger 327 away from the first busbar 321 and the end of the second interdigitated finger 326 away from the second busbar 322 along the length of the second interdigitated finger 326 or the second pseudo-finger 327 is 0.15λ to 0.25λ; where λ is twice the shortest distance between the center line of the first interdigitated finger 324 and the center line of the second interdigitated finger 326, which is the period length of the interdigitated finger electrode.

[0206] Specifically, when the second pseudofinger 327 has a second tip 3271 at the end away from the first busbar 321, the minimum distance between the second tip 3271 and the second forked finger 326 in the length direction of the second forked finger 326 or the second pseudofinger 327 is 0.15λ to 0.25λ; when the second forked finger 326 has a second tip 3261 at the end away from the second busbar 322, the minimum distance between the second tip 3261 and the second pseudofinger 3261 in the length direction of the second forked finger 326 or the second pseudofinger 327 is 0.15λ to 0.25λ; when both the second pseudofinger 327 and the forked finger 327 have second tips at the ends away from the first busbar 321 and the second forked finger 327, the minimum distance between the two second tips in the length direction of the second forked finger 326 or the second pseudofinger 327 is 0.15λ to 0.25λ.

[0207] In some embodiments, in the second projection pattern, the distance difference between the point on the second side furthest from the first busbar 321 and the point on the second side closest to the first busbar 321 in the length direction of the second interdigit 326 is 0.1λ to 0.25λ.

[0208] Along the direction parallel to the piezoelectric material layer 31 and parallel to the length of the first busbar 321, the width of the second pseudo-finger 327 is 0.2λ to 0.3λ;

[0209] Along the length direction of the second pseudofinger 327, the minimum distance between the end face of the first tip 3271 of the second pseudofinger 327 and the end of the second pseudofinger 327 near the first busbar 321 is 0.15λ to 0.25λ.

[0210] In some embodiments, the length directions of the first busbar 321 and the second busbar 322 are parallel, and the widths of the first busbar 321 and the second busbar 322 are 0.1λ to 0.25λ.

[0211] It should be noted that the size limitation in this embodiment can also be seen in Figure 6A, which will not be repeated here.

[0212] Referring again to Figures 4A-4D, the first interdigitated finger 324, the first pseudo-finger 325, and the first tip, along with the second interdigitated finger 326, the second pseudo-finger 327, and the second tip, constitute one cycle of the transducer 32. The transducer 32 may include multiple cycles. In some embodiments, within one cycle, the changing trends of the end faces of the first and second tips may be consistent or inconsistent, i.e., the changing trends of the hypotenuses of the first or second projected pattern. In some embodiments, the changing trends of the end faces of the first and second tips may be consistent or inconsistent in different cycles. For example, referring to Figure 4D, the changing trends of the first tip 3251 and the first tip 3241 are consistent, and their slopes are the same, thus forming mutually parallel inclined planes. In some embodiments, the changing trends of the first tip 3251 and the first tip 3241 are also consistent with the changing trends of the second tip 3271 and the second tip 3261. In some embodiments, the changing trends of the first tip and the second tip are consistent within each cycle of the transducer 32.

[0213] Referring to Figure 8, in one embodiment, the transducer 31 further includes a first auxiliary busbar 3211 and a second auxiliary busbar 3221; wherein, the first auxiliary busbar 3211 is disposed on the side of the first busbar 321 away from the second busbar 322, the first auxiliary busbar 3211 is parallel to and spaced apart from the first busbar 3211, and the first auxiliary busbar 3211 and the first busbar 321 are connected by a first connecting post 3212; the second auxiliary busbar 3221 is disposed on the side of the second busbar 322 away from the first busbar 321, the second auxiliary busbar 3221 is parallel to and spaced apart from the second busbar 322, and the second auxiliary busbar 3221 and the second busbar 322 are connected by a second connecting post 3222.

[0214] Specifically, the first auxiliary busbar 3211 and the second auxiliary busbar 3221 are located on the surface of the piezoelectric material layer 31.

[0215] In this embodiment, a first connecting post 3212 is disposed between the first auxiliary busbar 3211 and the first busbar 321. One end of the first connecting post 3212 is connected to the first auxiliary busbar 3211, and the other end of the first connecting post 3212 is connected to the first busbar 321. In one embodiment, the first auxiliary busbar 3211 receives an electrical signal and feeds it into the first busbar 321 through the first connecting post 3212, thereby causing the piezoelectric material layer 31 near the first interdigital finger 324 to vibrate and generate sound waves. The sound velocity of the piezoelectric material layer 31 corresponding to the first auxiliary busbar 3211 may be different from the sound velocity of the piezoelectric material layer 31 between the first auxiliary busbar 3211 and the first busbar 321. The sound waves may be reflected on the piezoelectric material layer 31 corresponding to the first auxiliary busbar 3211 to further prevent sound wave leakage.

[0216] The second auxiliary busbar 3221 is disposed on the side of the second busbar 322 opposite to the first busbar 321, and the second auxiliary busbar 3221 and the second busbar 322 are spaced apart. The second connecting post 3222 is disposed between the second auxiliary busbar 3221 and the second busbar 322, with one end of the second connecting post 3222 connected to the second auxiliary busbar 3221 and the other end of the second connecting post 3222 connected to the second busbar 322. In one embodiment, the second auxiliary busbar 3221 receives an electrical signal and feeds it into the second busbar 322 through the second connecting post 3222, thereby causing the piezoelectric material layer 31 near the second interdigital finger 326 to vibrate and generate sound waves. The sound velocity of the piezoelectric material layer 31 corresponding to the second auxiliary busbar 3221 can be different from the sound velocity of the piezoelectric material layer 31 between the second auxiliary busbar 3221 and the second busbar 322. The sound wave can be reflected on the piezoelectric material layer 31 corresponding to the second auxiliary busbar 3221 to further prevent sound wave leakage.

[0217] It is understood that the positions of the first connecting post 3212 and the second connecting post 3222 can be implemented in various ways, as long as the projection of the first connecting post 3212 onto the first busbar 321 along the length direction of the first interdigitated finger 324 coincides, and the projection of the second connecting post 3222 onto the second busbar 322 along the length direction of the second interdigitated finger 326 coincides. In one embodiment, the first connecting post 3212 is an extension of the first interdigitated finger 321 along its length direction, and the second connecting post 3222 is an extension of the second interdigitated finger 326 along its length direction. That is, the projections of the first connecting post 3212 and the first interdigitated finger 324 onto the first busbar 321 along the length direction of the first interdigitated finger 324 completely coincide, and the projections of the second connecting post 3222 and the second interdigitated finger 326 onto the second busbar 322 along the length direction of the second interdigitated finger 326 completely coincide.

[0218] Referring again to Figure 8, the distance L31 between the first busbar 321 and the first auxiliary busbar 3211 is 0.6λ to 1.2λ, and the distance L32 between the second busbar 322 and the second auxiliary busbar 3221 is 0.6λ to 1.2λ; where λ is twice the shortest distance L1 between the center line of the first interdigitated finger 324 and the center line of the second interdigitated finger.

[0219] Referring again to Figure 8, the dimensions in the aforementioned embodiments are clearly defined in Figure 8. Figure 8 is a schematic diagram showing that the first pseudo-finger 325 and the first interdigital finger 324 both include a first tip with a consistent tip inclination, and the second pseudo-finger 327 and the second interdigital finger 326 both include a second tip with a consistent tip inclination. In the figure,

[0220] Gap1 represents the minimum distance between the end of the first pseudofinger 325 away from the second busbar 322 and the end of the first interdigitated finger 324 away from the first busbar 321, along the length direction of the first interdigitated finger 324 or the first pseudofinger 325. Gap1 takes values ​​from 0.15λ to 0.25λ, for example, values ​​of 0.15λ, 0.2λ, and 0.25λ.

[0221] The widths of the first busbar 321 and the second busbar 322 are 0.1λ to 0.25λ.

[0222] 'a' represents the width of the first pseudo-finger 325 and the second pseudo-finger 327 along the length direction parallel to the piezoelectric material layer 31 and parallel to the first busbar 321. The value of 'a' is 0.2λ to 0.3λ, for example, 0.4λ, 0.5λ, and 0.6λ.

[0223] L22 represents the minimum distance between the end face of the first tip 3251 of the first pseudofinger 325 and the end of the first pseudofinger 325 near the second busbar 322 along the length direction of the first pseudofinger 325. The value of L22 is 0.15λ to 0.25λ, for example, 0.15λ, 0.2λ, and 0.25λ.

[0224] Gap2 represents the minimum distance between the end of the second pseudofinger 327 away from the first busbar 321 and the end of the second interdigitated finger 326 away from the second busbar 322, along the length of the second interdigitated finger 326 or the second pseudofinger 327. Gap2 ranges from 0.15λ to 0.25λ, for example, values ​​of 0.15λ, 0.2λ, and 0.25λ.

[0225] L21 represents the minimum distance between the end face of the first tip 3271 of the second pseudofinger 327 and the end of the second pseudofinger 327 closest to the first busbar 321 along the length direction of the second pseudofinger 327. The value of L21 is 0.15λ to 0.25λ, for example, 0.15λ, 0.2λ, and 0.25λ.

[0226] With the above configuration, the length of the first dummy finger 325 is moderate, ensuring that it has sufficient length along the length direction perpendicular to the second busbar 322 to allow sound waves to be scattered on the piezoelectric material layer 31 near the first dummy finger 325, while also preventing the first dummy finger 325 from being too long. Similarly, the length of the second dummy finger 327 is moderate, ensuring that it has sufficient length along the length direction perpendicular to the first busbar 321 to allow sound waves to be scattered on the piezoelectric material layer 31 near the second dummy finger 327, while also preventing the second dummy finger 327 from being too long.

[0227] Referring to FIG9, in one embodiment, based on the foregoing embodiment, the transducer 32 further includes a first reverse pseudo-finger 3252, which is disposed on the side of the second busbar 322 opposite to the first busbar 321.

[0228] That is, the first reverse pseudo-finger 3252 is disposed on the piezoelectric material layer 31, and the first reverse pseudo-finger 3252 is located outside the transmission channel 323. In one embodiment, the first reverse pseudo-finger 3252 is connected to the second busbar 322, which can be understood as the first reverse pseudo-finger 3252 contacting the second busbar 322. For example, the first reverse pseudo-finger 3252 and the second busbar 322 can be an integral structure, or the first reverse pseudo-finger 3252 and the second busbar 322 can be connected by welding or other means. In one embodiment, the first reverse pseudo-finger 3252 and the second busbar 322 can also be spaced apart. In one embodiment, the projections of the first reverse pseudo-finger 3252 and the first pseudo-finger 325 onto the second busbar 322 along the length direction of the first pseudo-finger 325 at least partially overlap. In one embodiment, the projections of the first reverse pseudo-finger 3252 and the first pseudo-finger 325 onto the second busbar 322 along the length direction of the first pseudo-finger 325 can also form a gap.

[0229] Through the above configuration, the first reverse pseudo-finger 3252 can increase the density of the second busbar 322 on the side away from the transmission channel 323, thereby preventing the formation of acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode), reducing noise generated by the coupling between this acoustic wave and the acoustic wave corresponding to the second resonance, and improving communication performance. Furthermore, the sound velocity of the piezoelectric material layer 31 where the first reverse pseudo-finger 3252 is located is lower than the sound velocity of the piezoelectric material layer 31 on the side of the first reverse pseudo-finger 3252 away from the transmission channel 323. Therefore, acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode) and the acoustic waves corresponding to the second resonance (acoustic waves corresponding to the SH mode) will be scattered (e.g., reflected and / or refracted) on the piezoelectric material layer 31 near the first reverse pseudo-finger 3252, preventing the coupling of acoustic waves with frequencies higher than the anti-resonance point of the first resonance and the acoustic waves corresponding to the second resonance, further reducing noise and improving communication performance.

[0230] Referring again to FIG9, in one embodiment, the transducer 32 further includes a second reverse pseudo-finger 3272, which is disposed on the side of the first busbar 321 opposite to the second busbar 322.

[0231] That is, the second reverse pseudo-finger 3272 is disposed on the piezoelectric material layer 31, and the second reverse pseudo-finger 3272 is located outside the transmission channel 323. In one embodiment, the second reverse pseudo-finger 3272 is connected to the first busbar 321, which can be understood as the second reverse pseudo-finger 3272 contacting the first busbar 321. For example, the second reverse pseudo-finger 3272 and the first busbar 321 can be an integral structure, or the second reverse pseudo-finger 3272 and the first busbar 321 can be connected by welding or other means. In one embodiment, the second reverse pseudo-finger 3272 and the first busbar 321 can also be spaced apart. In one embodiment, the projections of the second reverse pseudo-finger 3272 and the second pseudo-finger 327 onto the first busbar 321 along the length direction of the second pseudo-finger 327 at least partially overlap. In one embodiment, the projections of the second reverse pseudo-finger 3272 and the second pseudo-finger 327 onto the first busbar 321 along the length direction of the second pseudo-finger 327 can also form a gap.

[0232] Through the above configuration, the second reverse pseudo-finger 3272 can increase the density of the first busbar 321 on the side away from the transmission channel 323, thereby preventing the formation of acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode), reducing noise generated by the coupling between this acoustic wave and the acoustic wave corresponding to the second resonance, and improving communication performance. Furthermore, the sound velocity of the piezoelectric material layer 31 where the second reverse pseudo-finger 3272 is located is lower than the sound velocity of the piezoelectric material layer 31 on the side of the second reverse pseudo-finger 3272 away from the transmission channel 323. Therefore, acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode) and the acoustic waves corresponding to the second resonance (acoustic waves corresponding to the SH mode) will be scattered (e.g., reflected and / or refracted) on the piezoelectric material layer 31 near the second reverse pseudo-finger 3272, preventing the coupling of acoustic waves with frequencies higher than the anti-resonance point of the first resonance and the acoustic waves corresponding to the second resonance, further reducing noise and improving communication performance.

[0233] Referring again to Figure 9, in one embodiment, the transducer 32 further includes a first auxiliary busbar 3211 and a second auxiliary busbar 3221; wherein,

[0234] The first auxiliary busbar 3211 is disposed on the side of the first busbar 321 away from the second busbar 322. The first auxiliary busbar 3211 is parallel to and spaced apart from the first busbar 3211, and the first auxiliary busbar 3211 is connected to the first busbar 3212 through the first connecting post 3212. The second auxiliary busbar 3221 is disposed on the side of the second busbar 322 away from the first busbar 321. The second auxiliary busbar 3221 is parallel to and spaced apart from the second busbar 322, and the second auxiliary busbar 3221 is connected to the second busbar 322 through the second connecting post 3222.

[0235] Specifically, the first auxiliary busbar 3211 and the second auxiliary busbar 3221 are located on the surface of the piezoelectric material layer 31.

[0236] In this embodiment, a first connecting post 3212 is disposed between the first auxiliary busbar 3211 and the first busbar 321. One end of the first connecting post 3212 is connected to the first auxiliary busbar 3211, and the other end of the first connecting post 3212 is connected to the first busbar 321. In one embodiment, the first auxiliary busbar 3211 receives an electrical signal and feeds it into the first busbar 321 through the first connecting post 3212, thereby causing the piezoelectric material layer 31 near the first interdigital finger 324 to vibrate and generate sound waves. The sound velocity of the piezoelectric material layer 31 corresponding to the first auxiliary busbar 3211 may be different from the sound velocity of the piezoelectric material layer 31 between the first auxiliary busbar 3211 and the first busbar 321. The sound waves may be reflected on the piezoelectric material layer 31 corresponding to the first auxiliary busbar 3211 to further prevent sound wave leakage. In one embodiment, a second reverse pseudo-finger 3272 is disposed between the first busbar 321 and the first auxiliary busbar 3211.

[0237] The second auxiliary busbar 3221 is disposed on the side of the second busbar 322 opposite to the first busbar 321, and the second auxiliary busbar 3221 and the second busbar 322 are spaced apart. The second connecting post 3222 is disposed between the second auxiliary busbar 3221 and the second busbar 322, with one end of the second connecting post 3222 connected to the second auxiliary busbar 3221 and the other end of the second connecting post 3222 connected to the second busbar 322. In one embodiment, the second auxiliary busbar 3221 receives an electrical signal and feeds it into the second busbar 322 through the second connecting post 3222, thereby causing the piezoelectric material layer 31 near the second interdigital finger 326 to vibrate and generate sound waves. The sound velocity of the piezoelectric material layer 31 corresponding to the second auxiliary busbar 3221 can be different from the sound velocity of the piezoelectric material layer 31 between the second auxiliary busbar 3221 and the second busbar 322. Sound waves can be reflected on the piezoelectric material layer 31 corresponding to the second auxiliary busbar 3221 to further prevent sound wave leakage. In one embodiment, a first reverse pseudo-finger 3252 is disposed between the second busbar 322 and the second auxiliary busbar 3221.

[0238] It is understood that the positions of the first connecting post 3212 and the second connecting post 3222 can be implemented in various ways, as long as the projection of the first connecting post 3212 onto the first busbar 321 along the length direction of the first interdigitated finger 324 coincides, and the projection of the second connecting post 3222 onto the second busbar 322 along the length direction of the second interdigitated finger 326 coincides. In one embodiment, the first connecting post 3212 is an extension of the first interdigitated finger 321 along its length direction, and the second connecting post 3222 is an extension of the second interdigitated finger 326 along its length direction. That is, the projections of the first connecting post 3212 and the first interdigitated finger 324 onto the first busbar 321 along the length direction of the first interdigitated finger 324 completely coincide, and the projections of the second connecting post 3222 and the second interdigitated finger 326 onto the second busbar 322 along the length direction of the second interdigitated finger 326 completely coincide.

[0239] Referring again to Figure 9, the distance L31 between the first busbar 321 and the first auxiliary busbar 3211 is 0.6λ to 1.2λ, and the distance L32 between the second busbar 322 and the second auxiliary busbar 3221 is 0.6λ to 1.2λ; where λ is twice the shortest distance L1 between the center line of the first interdigitated finger 324 and the center line of the second interdigitated finger.

[0240] Referring again to FIG9, in one embodiment, the first reverse pseudo-finger 3252 is connected to the second bus bar 322 and forms a gap with the second auxiliary bus bar 3221; the second reverse pseudo-finger 3272 is connected to the first bus bar 321 and forms a gap with the first auxiliary bus bar 3211.

[0241] Along a length direction parallel to the piezoelectric material layer 31 and perpendicular to the first busbar 321, the length of the first reverse pseudo-finger 3252 is L52, and the length of the second reverse pseudo-finger 3272 is L51. Both L51 and L52 have values ​​between 0.05λ and 0.2λ. For example, L51 and L52 can be 0.05λ, 0.1λ, 0.2λ, etc. Correspondingly, the distance between the first reverse pseudo-finger 3252 and the second busbar 322 is L62, and the distance between the second reverse pseudo-finger 3272 and the first busbar 321 is L61. L61 and L62 are between 0.6λ and 1.2λ (e.g., 0.6λ, 0.9λ, 1.2λ, etc.).

[0242] This configuration ensures that the length of the reverse spur is moderate, guaranteeing sufficient length along the length direction perpendicular to the first busbar 321 or the second busbar 322. This allows the reverse spur to suppress the formation of acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode), and to ensure that acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode) and the acoustic waves corresponding to the second resonance (acoustic waves corresponding to the SH mode) are scattered on the piezoelectric material layer 31 near the reverse spur. This configuration also prevents the reverse spur from being too wide, thus preventing acoustic waves from propagating outwards through the reverse spur, i.e., preventing acoustic wave leakage outwards from the reverse spur.

[0243] Referring to Figure 10, in one embodiment, the transducer 32 further includes a first auxiliary pseudo-finger 3244, which is disposed between the second busbar 322 and the first busbar 321. In one embodiment, the first forked finger 324 is connected to the first busbar 321 via the first auxiliary pseudo-finger 3244. This configuration reduces the sound velocity of the portion of the piezoelectric material layer 31 corresponding to the first auxiliary pseudo-finger 3244, causing the sound waves on the piezoelectric material layer 31 corresponding to the transmission channel 323 to be reflected at the location of the first auxiliary pseudo-finger 3244, thus preventing sound waves from leaking out of the first busbar 321.

[0244] For example, along the length direction parallel to the piezoelectric material layer 31 and parallel to the first busbar 321, the width of the first auxiliary dummy finger 3244 is greater than the width of the first interdigitated finger 324. This configuration can further reduce the sound velocity of the portion of the piezoelectric material layer 31 corresponding to the first auxiliary dummy finger 3244, and further prevent sound waves from leaking out of the first busbar 321.

[0245] Understandably, in one embodiment, the first auxiliary pseudofinger 3244 can be integrally formed with the first interdigital finger 324, meaning that the first auxiliary pseudofinger 3244 and the first interdigital finger 324 are formed simultaneously using the same process. In one embodiment, the first auxiliary pseudofinger 3244 and the first interdigital finger 324 can be made of the same material, but their widths are unequal, resulting in a lower sound velocity in the piezoelectric material layer 31 corresponding to the first auxiliary pseudofinger 3244, thereby causing sound waves to be reflected.

[0246] Referring to Figure 11, in the implementation of transducer 32 including a first auxiliary busbar 3211 and a first connecting post 3212, transducer 32 further includes a second auxiliary dummy finger 3245, which is disposed between the first auxiliary busbar 3211 and the first busbar 321. In one embodiment, the first connecting post 3212 is connected to the first busbar 321 via the second auxiliary dummy finger 3245. This configuration allows the second auxiliary dummy finger 3245 to further increase the density of the side of the first busbar 321 facing away from the second busbar 322, further preventing the formation of acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode), thereby reducing noise generated by coupling between this acoustic wave and the acoustic wave corresponding to the second resonance, and improving communication performance. In addition, the sound velocity of the piezoelectric material layer 31 where the second auxiliary pseudo-finger 3245 is located is less than the sound velocity of the piezoelectric material layer 31 on the side of the second reverse pseudo-finger 3272 away from the transmission channel 323. Therefore, the sound wave with a frequency higher than the anti-resonance point of the first resonance (the sound wave corresponding to the Rayleigh transverse mode) and the sound wave corresponding to the second resonance (the sound wave corresponding to the SH mode) will be scattered (such as reflected and / or refracted) on the piezoelectric material layer 31 near the second auxiliary pseudo-finger 3245 to prevent the sound wave with a frequency higher than the anti-resonance point of the first resonance from coupling with the sound wave corresponding to the second resonance, further reducing noise and further improving communication performance.

[0247] For example, along the length direction parallel to the piezoelectric material layer 31 and parallel to the first busbar 321, the width of the second auxiliary dummy finger 3245 is greater than the width of the first connecting post 3212. This configuration increases the mass of the second auxiliary dummy finger 3245, further preventing the formation of acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode), and improves the reflection effect on acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode) and acoustic waves corresponding to the second resonance (acoustic waves corresponding to the SH mode), thereby further preventing the coupling of acoustic waves with frequencies higher than the anti-resonance point of the first resonance and acoustic waves corresponding to the second resonance.

[0248] Referring again to Figure 11, in some embodiments, the transducer 32 further includes a third auxiliary pseudo-finger 3273, which is disposed between the first auxiliary busbar 3211 and the first busbar 321. In one embodiment, the third auxiliary pseudo-finger 3273 is connected to the first auxiliary busbar 3211. In another embodiment, the third auxiliary pseudo-finger 3273 is spaced apart from the first reverse pseudo-finger 3272. This arrangement can reduce the sound velocity of the piezoelectric material layer 31 corresponding to the third auxiliary pseudo-finger 3273, so that the sound waves can be scattered on the piezoelectric material layer 31 corresponding to the third auxiliary pseudo-finger 3273, thereby preventing sound wave leakage. In addition, since the sound waves with frequencies higher than the anti-resonance point of the first resonance (the sound waves corresponding to the Rayleigh transverse mode) and the sound waves corresponding to the second resonance (the sound waves corresponding to the SH mode) are both scattered on the piezoelectric material layer 31 corresponding to the third auxiliary pseudo-finger 3273, the coupling of the sound waves with frequencies higher than the anti-resonance point of the first resonance and the sound waves corresponding to the second resonance can be further prevented.

[0249] For example, along the length direction perpendicular to the first busbar 321, the projections of the third auxiliary spur finger 3273 and the first reverse spur finger 3272 on the first busbar 321 may at least partially overlap. In one embodiment, the projections of the third auxiliary spur finger 3273 and the first reverse spur finger 3272 on the first busbar 321 may also be spaced apart.

[0250] Referring again to Figure 11, in some embodiments, the transducer 32 further includes a fourth auxiliary pseudo-finger 3274, which is disposed between the first auxiliary busbar 3211 and the first busbar 321. In one embodiment, the fourth auxiliary pseudo-finger 3274 is spaced apart from both the first auxiliary busbar 3211 and the first busbar 321. This arrangement reduces the sound velocity of the piezoelectric material layer 31 corresponding to the fourth auxiliary pseudo-finger 3274, allowing sound waves to be scattered on the piezoelectric material layer 31 corresponding to the fourth auxiliary pseudo-finger 3274, thus preventing sound wave leakage. Furthermore, since the sound waves with frequencies higher than the anti-resonance point of the first resonance (the sound waves corresponding to the Rayleigh transverse mode) and the sound waves corresponding to the second resonance (the sound waves corresponding to the SH mode) are both scattered on the piezoelectric material layer 31 corresponding to the fourth auxiliary pseudo-finger 3274, coupling between the sound waves with frequencies higher than the anti-resonance point of the first resonance and the sound waves corresponding to the second resonance can be further prevented.

[0251] In some embodiments, the fourth auxiliary pseudo-finger 3274 may be located between the third auxiliary pseudo-finger 3273 and the first reverse pseudo-finger 3272, and the fourth auxiliary pseudo-finger 3274 is spaced apart from both the third auxiliary pseudo-finger 3273 and the first reverse pseudo-finger 3272. For example, along the length direction perpendicular to the first busbar 321, the projections of the fourth auxiliary pseudo-finger 3274 and the first reverse pseudo-finger 3272 on the first busbar 321 may at least partially overlap; in one embodiment, the projections of the fourth auxiliary pseudo-finger 3274 and the first reverse pseudo-finger 3272 on the first busbar 321 may also be spaced apart.

[0252] Referring again to Figure 10, in one embodiment, the transducer 32 further includes a fifth auxiliary pseudo-finger 3262, which is disposed between the second busbar 322 and the first busbar 321. In one embodiment, the second forked finger 326 is connected to the second busbar 322 via the fifth auxiliary pseudo-finger 3262. This arrangement can reduce the sound velocity of a portion of the piezoelectric material layer 31 corresponding to the fifth auxiliary pseudo-finger 3262, causing the sound waves on the piezoelectric material layer 31 corresponding to the transmission channel 323 to be reflected at the location of the fifth auxiliary pseudo-finger 3262, thus preventing sound waves from leaking out of the second busbar 322.

[0253] For example, along the length direction parallel to the piezoelectric material layer 31 and parallel to the second busbar 322, the width of the fifth auxiliary pseudo-finger 3262 is greater than the width of the second interdigitated finger 326. This configuration can further reduce the sound velocity of the portion of the piezoelectric material layer 31 corresponding to the fifth auxiliary pseudo-finger 3262, and further prevent sound waves from leaking out of the second busbar 322.

[0254] It is understandable that the fifth auxiliary pseudofinger 3262 can be integrally formed with the second interdigital finger 326, meaning that the fifth auxiliary pseudofinger 3262 and the second interdigital finger 326 are formed simultaneously using the same process. In one embodiment, the fifth auxiliary pseudofinger 3262 and the second interdigital finger 326 can be made of the same material, but their widths are unequal, resulting in a lower sound velocity in the piezoelectric material layer 31 corresponding to the fifth auxiliary pseudofinger 3262, thereby causing sound waves to be reflected.

[0255] Referring again to Figure 10, in the implementation of the transducer 32 including a second auxiliary busbar 3221 and a second connecting post 3222, the transducer 32 further includes a sixth auxiliary dummy finger 3263, which is disposed between the second auxiliary busbar 3221 and the second busbar 322. In one embodiment, the second connecting post 3222 is connected to the second busbar 322 via the sixth auxiliary dummy finger 3263. This configuration allows the sixth auxiliary dummy finger 3263 to further increase the density of the side of the second busbar 322 facing away from the first busbar 321, further preventing the formation of acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode), thereby reducing noise generated by coupling between this acoustic wave and the acoustic wave corresponding to the second resonance, and improving communication performance. In addition, the sound velocity of the piezoelectric material layer 31 where the sixth auxiliary pseudo-finger 3263 is located is less than the sound velocity of the piezoelectric material layer 31 on the side of the second reverse pseudo-finger 3254 away from the transmission channel 323. Therefore, the sound wave with a frequency higher than the anti-resonance point of the first resonance (the sound wave corresponding to the Rayleigh transverse mode) and the sound wave corresponding to the second resonance (the sound wave corresponding to the SH mode) will be scattered (such as reflected and / or refracted) on the piezoelectric material layer 31 near the sixth auxiliary pseudo-finger 3263 to prevent the sound wave with a frequency higher than the anti-resonance point of the first resonance from coupling with the sound wave corresponding to the second resonance, further reducing noise and further improving communication performance.

[0256] For example, along the length direction parallel to the piezoelectric material layer 31 and parallel to the second busbar 322, the width of the sixth auxiliary dummy finger 3263 is greater than the width of the second connecting post 3222. This configuration increases the mass of the sixth auxiliary dummy finger 3263, further preventing the formation of acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode), and improves the reflection effect of acoustic waves with frequencies higher than the anti-resonance point of the first resonance (acoustic waves corresponding to the Rayleigh transverse mode) and acoustic waves corresponding to the second resonance (acoustic waves corresponding to the SH mode), thereby further preventing the coupling of acoustic waves with frequencies higher than the anti-resonance point of the first resonance and acoustic waves corresponding to the second resonance.

[0257] Referring again to Figure 11, in some embodiments, the transducer 32 further includes a seventh auxiliary pseudo-finger 3255, which is disposed between the second auxiliary busbar 3221 and the second busbar 322. In one embodiment, the seventh auxiliary pseudo-finger 3255 is connected to the second auxiliary busbar 3221; in another embodiment, the seventh auxiliary pseudo-finger 3255 is spaced apart from the second reverse pseudo-finger 3254. This arrangement can reduce the sound velocity of the piezoelectric material layer 31 corresponding to the seventh auxiliary pseudo-finger 3255, so that the sound wave can be scattered on the piezoelectric material layer 31 corresponding to the seventh auxiliary pseudo-finger 3255, thereby preventing sound wave leakage. In addition, since the sound wave with a frequency higher than the anti-resonance point of the first resonance (the sound wave corresponding to the Rayleigh transverse mode) and the sound wave corresponding to the second resonance (the sound wave corresponding to the SH mode) are both scattered on the piezoelectric material layer 31 corresponding to the seventh auxiliary pseudo-finger 3255, the coupling of the sound wave with a frequency higher than the anti-resonance point of the first resonance and the sound wave corresponding to the second resonance can be further prevented.

[0258] For example, along the length direction perpendicular to the second busbar 322, the projections of the seventh auxiliary spur finger 3255 and the second reverse spur finger 3254 on the second busbar 322 may at least partially overlap; in one embodiment, the projections of the seventh auxiliary spur finger 3255 and the second reverse spur finger 3254 on the second busbar 322 may also be spaced apart.

[0259] Referring again to Figure 11, in some embodiments, the transducer 32 further includes an eighth auxiliary pseudo-finger 3256, which is disposed between the second auxiliary busbar 3221 and the second busbar 322. In one embodiment, the eighth auxiliary pseudo-finger 3256 is spaced apart from both the second auxiliary busbar 3221 and the second busbar 322. This arrangement reduces the sound velocity of the piezoelectric material layer 31 corresponding to the eighth auxiliary pseudo-finger 3256, allowing sound waves to be scattered on the piezoelectric material layer 31 corresponding to the eighth auxiliary pseudo-finger 3256, thus preventing sound wave leakage. Furthermore, since both the sound waves with frequencies higher than the anti-resonance point of the first resonance (the sound waves corresponding to the Rayleigh transverse mode) and the sound waves corresponding to the second resonance (the sound waves corresponding to the SH mode) are scattered on the piezoelectric material layer 31 corresponding to the eighth auxiliary pseudo-finger 3256, coupling between the sound waves with frequencies higher than the anti-resonance point of the first resonance and the sound waves corresponding to the second resonance can be further prevented.

[0260] In some embodiments, the eighth auxiliary pseudo-finger 3256 may be located between the seventh auxiliary pseudo-finger 3255 and the second reverse pseudo-finger 3254, and the eighth auxiliary pseudo-finger 3256 is spaced apart from the seventh auxiliary pseudo-finger 3255 and the second reverse pseudo-finger 3254. For example, along the length direction perpendicular to the second busbar 322, the projections of the eighth auxiliary pseudo-finger 3256 and the second reverse pseudo-finger 3254 on the second busbar 322 may at least partially overlap; in one embodiment, the projections of the eighth auxiliary pseudo-finger 3256 and the second reverse pseudo-finger 3254 on the second busbar 322 may also be spaced apart.

[0261] In some embodiments, the auxiliary pseudo-finger in the foregoing embodiments is not limited to the combinations shown in Figures 10 and 11; combinations of the cases in Figures 10 and 11 may also be used. Alternatively, in some embodiments, other permutations and combinations are also possible.

[0262] As shown in Figure 12, in one embodiment, based on the foregoing embodiments, the transducer 32 further includes an expansion portion and / or a protrusion; wherein,

[0263] An expansion portion and / or a protrusion are provided at the position of the first interdigitated finger 324 near the first busbar 321 and at the position of the first interdigitated finger 324 near the second busbar 322;

[0264] An expansion portion and / or a protrusion are provided at the position of the second forked finger 326 near the first busbar 321 and at the position of the second forked finger 326 near the second busbar 322.

[0265] Specifically, in this embodiment, the expansion portion is also referred to as the Hammer structure, and the protrusion is also referred to as the Piston structure.

[0266] For example, the dashed box in Figure 12 is a right view of the transducer 32 from the right-side perspective of the illustration. In one embodiment, an expansion portion 3242 and an expansion portion 3243 are respectively provided at the end of the first interdigitator 324 near the first busbar 321 and at the end of the first interdigitator 324 near the second busbar 322.

[0267] In one embodiment, along the length of the first busbar 321, the width of the expansion portions 3242 and 3243 is greater than the width of the first interdigitated finger 324 or the second interdigitated finger 326. For example, along the width direction perpendicular to the length of the first busbar 321, the dimensions of the expansion portions 3242 and 3243 are greater than the dimensions at other locations of the first interdigitated finger 324, such that the sound velocity of the piezoelectric material layer 31 corresponding to the expansion portions 3242 and 3243 is lower than the sound velocity of the piezoelectric material layer 31 corresponding to the first interdigitated fingers 324 on both sides. This allows sound waves to be reflected in this region, preventing sound waves from leaking to the outside of the first busbar 321 and the second busbar 322 (towards the side opposite to the transmission channel 323).

[0268] In one embodiment, expansion portions 3242 and 3243 are respectively provided at the end of the second interdigit 326 near the first busbar 321 and the end of the second interdigit 326 near the second busbar 322, so that sound waves can be reflected in this part of the region to further prevent sound waves from leaking to the outside of the first busbar 321 and the second busbar 322.

[0269] In one embodiment, a protrusion 3246 and a protrusion 3247 are respectively provided at one end of the first interdigital finger 324 near the first busbar 321 and at one end of the first interdigital finger 324 near the second busbar 322. In one embodiment, the size of the protrusions 3246 and 3247 is larger than the size of other positions of the first interdigital finger 324 along a direction perpendicular to the surface of the piezoelectric material layer 31, further suppressing cross-dip.

[0270] In one embodiment, the second interdigitated finger 326 near the first busbar 321 and the second interdigitated finger 326 near the second busbar 322 are also provided with protrusions 3246 and 3247 respectively. The protrusions can increase the sound velocity difference of the corresponding piezoelectric material layer, thereby better suppressing transverse mode.

[0271] In one embodiment, as shown in the right view within the dashed box in FIG12, protrusions 3246 and 3247 are disposed on the side of the first forked finger 324 or the second forked finger 326 away from the piezoelectric material layer 31.

[0272] In one embodiment, protrusions 3246 and 3247 are disposed at the locations of the expansion portions. As shown in FIG12, protrusions 3246 and 3247 are respectively disposed at the corresponding positions of expansion portions 3242 and 3243. The protrusions can further increase the sound velocity difference of the corresponding piezoelectric material layers based on the expansion portions, thereby better suppressing transverse modes.

[0273] In one embodiment, the length of the expansion portion is 0.6λ to 1.2λ, and the width of the expansion portion is 0.05µm to 0.15µm larger than the width of the first interdigital finger 324 or the second interdigital finger 326; wherein, the length direction of the expansion portion is along the length direction of the first interdigital finger 324.

[0274] Specifically, the width direction of the expansion section is along the length direction of the first busbar 321.

[0275] For example, as shown in FIG12, the lengths of the expansion portions 3242 and 3243 are 0.6λ to 1.2λ, for example, 0.6λ, 1.0λ, and 1.2λ, so that the expansion portions have sufficient length to prevent leakage from the area where the first busbar 321 is located.

[0276] In one embodiment, along the width direction perpendicular to the length of the first busbar 321, the size of the expansion portion 3242 is larger than the size of other positions of the first interdigital fingers 324, by 0.05µm to 0.15µm; similarly, along the width direction perpendicular to the length of the first busbar 321, the size of the expansion portion 3243 is larger than the size of other positions of the second interdigital fingers 326, by 0.05µm to 0.15µm. This arrangement ensures that the sound velocity of the piezoelectric material layer 31 corresponding to the expansion portion 324 is lower than the sound velocity of the piezoelectric material layers 31 corresponding to the first interdigital fingers 324 on both sides, thereby allowing sound waves to be reflected in this region, preventing sound waves from leaking to the outside of the first busbar 321 and the second busbar 322 (towards the side opposite to the transmission channel 323).

[0277] In one embodiment, the length of the protrusion is 0.05 μm to 0.15 μm shorter than the length of the expansion portion, the width of the protrusion is 0.05 μm to 0.15 μm shorter than the width of the expansion portion, and the thickness of the protrusion is 0.01λ to 0.03λ.

[0278] Specifically, the length and width directions of the protrusions are consistent with those of the expansion portions, and the thickness direction of the protrusions is perpendicular to the piezoelectric material layer 31. For example, the length and width of protrusions 3246 and 3247 are 0.05µm to 0.15µm smaller than the corresponding expansion portions 3242 and 3243, for example, 0.05µm, 0.10µm, and 0.15µm. The thickness of protrusions 3246 and 3247 is 0.01λ to 0.03λ, for example, 0.01λ, 0.02λ, and 0.03λ.

[0279] As shown in Figure 13, an embodiment of this application also provides a method for fabricating a resonator. This method is used to fabricate the resonator described in the foregoing embodiments, and includes:

[0280] S20. A metal layer is formed by depositing a film on the surface of the piezoelectric material layer.

[0281] In the specific implementation process, the piezoelectric material layer 31 is located on the substrate 35, and the whole consisting of the substrate 35 and the piezoelectric material layer 31 can also be referred to as a wafer. In the fabrication process, the wafer can first be cleaned, and then a sputtering deposition can be performed on the wafer surface to form a metal thin film (i.e., a metal layer) on the piezoelectric material layer 31.

[0282] In one embodiment, the metal layer includes:

[0283] The adhesive layer can be made of materials such as Ti, Cr, and Ni, and has a thickness of 2–40 nm.

[0284] Single-layer electrode metal or multi-layer electrode metal. The material of single-layer electrode metal can be W, Mo, etc., with a thickness of 50-500 nm. The material combination of multi-layer electrode metal can be W / Al, Mo / Al, etc. In multi-layer electrode metal, the function of the lower electrode is to reduce the sound velocity, with a thickness of 50-200 nm, and the function of the upper electrode is to reduce resistance and reduce insertion loss, with a thickness of 100-300 nm.

[0285] S40. Apply adhesive to the metal layer to form an adhesive layer;

[0286] S60. According to the structure of the transducer, expose and develop the adhesive layer;

[0287] In the specific implementation process, according to the structure of the interdigitated fingers, pseudo-finger and busbar in the transducer 32, the adhesive layer is exposed and developed to expose the metal layer of the part that needs to be etched.

[0288] S80. The metal layer is etched according to the developed adhesive layer to form the transducer on the surface of the piezoelectric material layer.

[0289] In the specific implementation process, the exposed metal layer that needs to be etched is etched to remove the adhesive, and the remaining metal structure is the structure of the interdigitated fingers, pseudo-finger and busbar of the transducer 32.

[0290] As shown in Figure 14, an embodiment of this application also provides a method for fabricating a resonator. This method is used to fabricate the resonator described in the foregoing embodiments, and includes:

[0291] S200: Apply adhesive to the surface of the piezoelectric material layer to form an adhesive layer;

[0292] In the specific implementation process, the piezoelectric material layer 31 is located on the substrate 35, and the whole consisting of the substrate 35 and the piezoelectric material layer 31 can also be referred to as a wafer. In the fabrication process, the wafer can be cleaned first, and then a resist can be applied to the surface of the wafer.

[0293] S400. According to the structure of the transducer, the adhesive layer is exposed and developed;

[0294] In the specific implementation process, according to the structure of the interdigitated fingers, pseudo-finger and busbar in the transducer 32, the adhesive layer is exposed and developed to form an adhesive layer corresponding to the structure of the transducer 32, exposing the piezoelectric material layer 31 that needs to be coated to form the electrode.

[0295] S600. The developed adhesive layer is coated and the adhesive layer is peeled off to form the transducer on the surface of the piezoelectric material layer.

[0296] In the specific implementation process, a coating is applied to the adhesive layer frame to form metal electrodes in the piezoelectric material layer 31, which are the interdigitated fingers, pseudo-finger and busbar structure of the transducer 32. The adhesive layer is then peeled off to obtain the structure of the transducer 32.

[0297] In one embodiment, the metal electrode has a multilayer structure, specifically including:

[0298] The adhesive layer can be made of materials such as Ti, Cr, and Ni, and has a thickness of 2–40 nm.

[0299] Single-layer electrode metal or multi-layer electrode metal. The material of single-layer electrode metal can be Pt, Au, etc., with a thickness of 50-500 nm. The material combination of multi-layer electrode metal can be Pt / Al, Pt / Cu, Pt / Au, etc. In multi-layer electrode metal, the function of the lower electrode is to reduce the sound velocity, with a thickness of 50-200 nm, and the function of the upper electrode is to reduce resistance and reduce insertion loss, with a thickness of 100-300 nm.

[0300] This application also provides a method for fabricating a resonator. The method of this embodiment is used to fabricate the resonator described in the foregoing embodiments, and includes:

[0301] A first busbar and a second busbar are formed on the surface of the piezoelectric material layer, and the first busbar and the second busbar are spaced apart.

[0302] A first forked finger and a second forked finger are formed on the surface of the piezoelectric material layer, with the first forked finger and the second forked finger being spaced apart.

[0303] A first pseudo-finger is formed on the surface of the piezoelectric material layer;

[0304] Wherein, the first forked finger and the second forked finger are disposed between the first busbar and the second busbar, the first forked finger is connected to the first busbar, and the second forked finger is connected to the second busbar; wherein, the first spur finger corresponds to the first forked finger, the first spur finger is disposed on the side of the second busbar close to the first busbar, the end of the first spur finger away from the second busbar and the end of the first forked finger away from the first busbar are spaced apart in the length direction of the first forked finger, and the end of the first spur finger away from the second busbar and / or the end of the first forked finger away from the first busbar are provided with a first tip;

[0305] Along a direction perpendicular to the surface of the piezoelectric material layer, the first tip forms a first projection on the surface of the piezoelectric material layer; the first side of the first projection pattern corresponding to the first projection gradually decreases or increases in perpendicular distance between the first side and the first busbar on the surface of the piezoelectric material layer; the first side is the side corresponding to the end face of the first tip.

[0306] It should be noted that the resonator prepared by the method of this embodiment is the same as that in the previous embodiment. The specific implementation method and the technical effects achieved can be referred to the previous embodiment, and will not be repeated here.

[0307] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A resonator, characterized in that, include: piezoelectric material layer; A transducer, wherein the transducer is disposed on the surface of the piezoelectric material layer, the transducer comprising: A first busbar and a second busbar are provided at an interval; A first forked finger and a second forked finger are disposed at intervals between the first busbar and the second busbar. The first forked finger is connected to the first busbar, and the second forked finger is connected to the second busbar. The first pseudo-finger corresponds to the first interdigitated finger. The first pseudo-finger is disposed on the side of the second busbar close to the first busbar. The end of the first pseudo-finger away from the second busbar and the end of the first interdigitated finger away from the first busbar are spaced apart in the length direction of the first interdigitated finger. The end of the first pseudo-finger away from the second busbar and / or the end of the first interdigitated finger away from the first busbar are provided with a first tip. Along a direction perpendicular to the surface of the piezoelectric material layer, the first tip forms a first projection on the surface of the piezoelectric material layer; the first side of the first projection pattern corresponding to the first projection gradually decreases or increases in perpendicular distance between the first side and the first busbar on the surface of the piezoelectric material layer; the first side is the side corresponding to the end face of the first tip.

2. The resonator according to claim 1, characterized in that, When both the first prosthetic finger and the first interdigitated finger are provided with the first tip, the changing trend of the vertical distance between the first side formed by the first tip of the first prosthetic finger and the first busbar is the same as the changing trend of the vertical distance between the first side formed by the first tip of the first interdigitated finger and the first busbar.

3. The resonator according to claim 1 or 2, characterized in that, The first side forms an acute angle α with the length direction of the first interdigitated finger or the first prosthetic finger, where 40°≤α≤85°.

4. The resonator according to claim 1 or 2, characterized in that, The first side forms an acute angle α with the length direction of the first interdigitated finger or the first prosthetic finger, where 55°≤α≤75°.

5. The resonator according to claim 1 or 2, characterized in that, The first side forms an acute angle α with the length direction of the first interdigitated finger or the first prosthetic finger, where 60°≤α≤65°.

6. The resonator according to any one of claims 1 to 5, characterized in that, The minimum distance between the end of the first pseudofinger away from the second busbar and the end of the first interdigitated finger away from the first busbar in the length direction of the first interdigitated finger or the first pseudofinger is 0.15λ to 0.25λ. Wherein, λ is twice the shortest distance between the center line of the first interdigitated finger and the center line of the second interdigitated finger.

7. The resonator according to claim 6, characterized in that, In any of the first projection patterns, the distance difference between the point on the first side furthest from the first busbar and the point on the first side closest to the first busbar in the length direction of the first interdigit is 0.1λ to 0.25λ. Along the direction parallel to the piezoelectric material layer and parallel to the length of the first busbar, the width of the first pseudo-finger is 0.2λ to 0.3λ; Along the length of the first prosthetic finger, the minimum distance between the end face of the first tip of the first prosthetic finger and the end of the first prosthetic finger near the second busbar is 0.15λ to 0.25λ.

8. The resonator according to any one of claims 1 to 7, characterized in that, The transducer further includes a second pseudo-finger, which corresponds to the second forked finger. The second pseudo-finger is disposed on the side of the first busbar close to the second busbar. The end of the second pseudo-finger away from the first busbar and the end of the second forked finger away from the second busbar are spaced apart in the length direction of the second forked finger. The end of the second pseudo-finger away from the first busbar and / or the end of the second forked finger away from the second busbar are provided with a second tip. Along a direction perpendicular to the surface of the piezoelectric material layer, the second tip forms a second projection on the surface of the piezoelectric material layer; the second side of the second projection pattern corresponding to the second projection gradually decreases or increases in perpendicular distance between the second side and the second busbar on the surface of the piezoelectric material layer; the second side is the side corresponding to the end face of the second tip.

9. The resonator according to claim 8, characterized in that, When both the second pseudofinger and the second interdigital finger are provided with a second tip, the changing trend of the distance between the second side formed by the second tip of the second pseudofinger and the second busbar is the same as the changing trend of the distance between the second side formed by the second tip of the second interdigital finger and the second busbar.

10. The resonator according to claim 8 or 9, characterized in that, The second side forms an acute angle β with the length direction of the second interdigitated finger or the second pseudo-finger, where 40°≤β≤85°.

11. The resonator according to claim 8 or 9, characterized in that, The second side forms an acute angle β with the length direction of the second interdigitated finger or the second pseudo-finger, where 55°≤β≤75°.

12. The resonator according to claim 8 or 9, characterized in that, The second side forms an angle β with the length direction of the second interdigitated finger or the second pseudo-finger, where 60°≤β≤65°.

13. The resonator according to any one of claims 8 to 12, characterized in that, The minimum distance between the end of the second pseudofinger away from the first busbar and the end of the second interdigitated finger away from the second busbar in the length direction of the second interdigitated finger or the second pseudofinger is 0.15λ to 0.25λ. Wherein, λ is twice the shortest distance between the center line of the first interdigitated finger and the center line of the second interdigitated finger.

14. The resonator according to claim 13, characterized in that, In any of the second projection patterns, the distance difference between the point on the second side furthest from the first busbar and the point on the second side closest to the first busbar in the length direction of the second interdigit is 0.1λ to 0.25λ. Along the direction parallel to the piezoelectric material layer and parallel to the length of the first busbar, the width of the second pseudo-finger is 0.2λ to 0.3λ; Along the length of the second prosthetic finger, the minimum distance between the end face of the second tip of the second prosthetic finger and the end of the second prosthetic finger near the first busbar is 0.15λ to 0.25λ.

15. The resonator according to any one of claims 1 to 14, characterized in that, The length directions of the first busbar and the second busbar are parallel, and the widths of the first busbar and the second busbar are 0.1λ to 0.25λ.

16. The resonator according to any one of claims 1 to 15, characterized in that, The transducer further includes a first auxiliary busbar and a second auxiliary busbar; wherein... The first auxiliary busbar is disposed on the side of the first busbar away from the second busbar. The first auxiliary busbar is parallel to and spaced apart from the first busbar, and the first auxiliary busbar is connected to the first busbar through a first connecting post. The second auxiliary busbar is disposed on the side of the second busbar away from the first busbar. The second auxiliary busbar is parallel to and spaced apart from the second busbar, and the second auxiliary busbar is connected to the second busbar through a second connecting post.

17. The resonator according to claim 16, characterized in that, The first connecting post is an extension of the first interdigitated finger in the length direction, and the second connecting post is an extension of the second interdigitated finger in the length direction.

18. The resonator according to any one of claims 1 to 15, characterized in that, The transducer further includes a first reverse spur finger, which is disposed on the side of the second busbar opposite to the first busbar; and / or, The transducer also includes a second reverse pseudo-finger, which is disposed on the side of the first busbar opposite to the second busbar.

19. The resonator according to claim 18, characterized in that, The transducer further includes a first auxiliary busbar and a second auxiliary busbar; wherein... The first auxiliary busbar is disposed on the side of the first busbar opposite to the second busbar. The first auxiliary busbar is parallel to and spaced apart from the first busbar, and the first auxiliary busbar is connected to the first busbar through a first connecting post. The second reverse dummy finger is disposed between the first busbar and the first auxiliary busbar. The second auxiliary busbar is disposed on the side of the second busbar away from the first busbar. The second auxiliary busbar is parallel to and spaced apart from the second busbar, and the second auxiliary busbar is connected to the second busbar through a second connecting post. The first reverse dummy finger is disposed between the second busbar and the second auxiliary busbar.

20. The resonator according to claim 16, 17 or 19, characterized in that, The distance between the first busbar and the first auxiliary busbar is 0.6λ to 1.2λ, and the distance between the second busbar and the second auxiliary busbar is 0.6λ to 1.2λ; where λ is twice the shortest distance between the center line of the first interdigitated finger and the center line of the second interdigitated finger.

21. The resonator according to any one of claims 1 to 20, characterized in that, The transducer further includes an expansion portion and / or a protrusion; wherein... The expansion portion and / or the protrusion are provided at both the position of the first interdigital finger near the first busbar and the position of the first interdigital finger near the second busbar; The expansion portion and / or the protrusion are provided at the positions of the second forked finger near the first busbar and the positions of the second forked finger near the second busbar.

22. The resonator according to claim 21, characterized in that, Along the length of the first busbar, the width of the expansion portion is greater than the width of the first forked finger or the second forked finger; the protrusion is disposed on the side of the first forked finger or the second forked finger away from the piezoelectric material layer.

23. The resonator according to claim 22, characterized in that, The protrusion is located at the position of the expansion portion.

24. The resonator according to any one of claims 21 to 23, characterized in that, The length of the expansion portion is 0.6λ to 1.2λ, and the width of the expansion portion is 0.05µm to 0.15µm larger than the width of the first interdigitated finger or the second interdigitated finger; the length direction of the expansion portion is along the length direction of the first interdigitated finger. Wherein, λ is twice the shortest distance between the center line of the first interdigitated finger and the center line of the second interdigitated finger.

25. The resonator according to claim 24, characterized in that, The length of the protrusion is 0.05µm to 0.15µm shorter than the length of the expansion portion, the width of the protrusion is 0.05µm to 0.15µm shorter than the width of the expansion portion, and the thickness of the protrusion is 0.01λ to 0.03λ.

26. A method for fabricating a resonator, characterized in that, The method is used to prepare a resonator as described in any one of claims 1 to 25, the method comprising: A metal layer is formed by depositing a film on the surface of the piezoelectric material layer. An adhesive layer is formed by applying adhesive to the metal layer. According to the structure of the transducer, the adhesive layer is exposed and developed; The metal layer is etched according to the developed adhesive layer to form the transducer on the surface of the piezoelectric material layer.

27. A method for fabricating a resonator, characterized in that, The method is used to prepare a resonator as described in any one of claims 1 to 25, the method comprising: An adhesive is applied to the surface of the piezoelectric material layer to form an adhesive layer. According to the structure of the transducer, the adhesive layer is exposed and developed; The transducer is formed on the surface of the piezoelectric material layer by coating and peeling off the developed adhesive layer.

28. A method for fabricating a resonator, characterized in that, The method includes: A first busbar and a second busbar are formed on the surface of the piezoelectric material layer, and the first busbar and the second busbar are spaced apart. A first forked finger and a second forked finger are formed on the surface of the piezoelectric material layer, with the first forked finger and the second forked finger being spaced apart. A first pseudo-finger is formed on the surface of the piezoelectric material layer; Wherein, the first forked finger and the second forked finger are disposed between the first busbar and the second busbar, the first forked finger is connected to the first busbar, and the second forked finger is connected to the second busbar; wherein, the first spur finger corresponds to the first forked finger, the first spur finger is disposed on the side of the second busbar close to the first busbar, the end of the first spur finger away from the second busbar and the end of the first forked finger away from the first busbar are spaced apart in the length direction of the first forked finger, and the end of the first spur finger away from the second busbar and / or the end of the first forked finger away from the first busbar are provided with a first tip; Along a direction perpendicular to the surface of the piezoelectric material layer, the first tip forms a first projection on the surface of the piezoelectric material layer; the first side of the first projection pattern corresponding to the first projection gradually decreases or increases in perpendicular distance between the first side and the first busbar on the surface of the piezoelectric material layer; the first side is the side corresponding to the end face of the first tip.

29. A filter, characterized in that, include: At least one resonator according to any one of claims 1 to 25.

30. A communication chip, characterized in that, include: The filter of claim 29, and a power amplifier or low-noise amplifier coupled to the filter.

31. An electronic device, characterized in that, include: The antenna and the communication chip of claim 30, wherein the communication chip is coupled to the antenna.

32. The electronic device according to claim 31, characterized in that, The communication frequency band of the communication chip includes the low-frequency band.

33. The electronic device according to claim 32, characterized in that, The communication frequency band of the communication chip includes any frequency band within the range of 300 MHz to 1000 MHz.

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