Surface acoustic-wave resonator, filter, communication chip, and electronic device

Abstract

A surface acoustic-wave resonator, a filter, a communication chip, and an electronic device, which aim to solve the problem of a poor communication performance. In a transducer of the surface acoustic-wave resonator, a first dummy finger is provided on the side of a first busbar that faces away from a second busbar, and the first dummy finger is connected to the first busbar. The first dummy finger can increase the density of the side of the first busbar that faces away from the second busbar, such that the formation of acoustic waves having frequencies higher than an anti-resonance point of a first resonance is prevented, thereby reducing clutter formed by the coupling between the acoustic waves and acoustic waves corresponding to a second resonance, and thus improving the communication performance. In addition, the acoustic waves having the frequencies higher than the anti-resonance point of the first resonance and the acoustic waves corresponding to the second resonance are scattered on a piezoelectric material layer near the first dummy finger, such that the coupling between the acoustic waves having the frequencies higher than the anti-resonance point of the first resonance and the acoustic waves corresponding to the second resonance is prevented, thereby further reducing clutter, and further improving the communication performance.

Description

Surface acoustic wave resonators, filters, communication chips and electronic devices

[0001] This application claims priority to Chinese patent application filed on August 28, 2024, with application number 202411201547.8 and entitled "Surface Acoustic Wave Resonator, Filter, Communication Chip and Electronic Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, specifically to a surface acoustic wave resonator, filter, communication chip, and electronic device. Background Technology

[0003] Electronic devices (such as mobile phones, tablets, and smartwatches) typically incorporate filters to filter signals and improve communication quality. In related technologies, filters generally include surface acoustic wave (SAW) resonators. When operating, SAW resonators convert electrical signals into sound waves, which include sound waves corresponding to a first mode and sound waves corresponding to a second mode. The resonant frequencies of the first and second mode sound waves are unequal. However, in related technologies, the first and second mode sound waves are prone to coupling, resulting in noise and affecting communication performance. Summary of the Invention

[0004] This application provides a surface acoustic wave resonator, filter, communication chip, and electronic device for reducing noise and improving communication performance.

[0005] In a first aspect, embodiments of this application provide a surface acoustic wave resonator, comprising: a piezoelectric material layer and a transducer; the transducer is disposed on the surface of the piezoelectric material layer and is used to drive the piezoelectric material layer to vibrate, thereby generating sound waves. The transducer includes: a first busbar, a second busbar, a first insert finger, and a second insert finger, the first busbar and the second busbar being spaced apart; the first insert finger and the second insert finger are spaced apart between the first busbar and the second busbar, the first insert finger being connected to the first busbar, and the second insert finger being connected to the second busbar. The transducer also includes a first dummy finger, the first dummy finger being disposed on the side of the first busbar facing away from the second busbar, and the first dummy finger being connected to the first busbar.

[0006] Through the above configuration, the density of the first busbar on the side away from the second busbar can be increased, 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. Furthermore, the increased density of the first busbar on the side away from the second busbar causes the sound velocity in the piezoelectric material layer where the first dummy finger is located to be lower than the sound velocity in the piezoelectric material layer on the side of the first dummy finger away from the first busbar. 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 dummy 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 improving communication performance.

[0007] In some embodiments that may include the above embodiments, the transducer further includes a first auxiliary busbar and a first connecting post. The first auxiliary busbar is disposed on the side of the first busbar away from the second busbar, and the first auxiliary busbar is disposed parallel to and spaced apart from the first busbar. The first connecting post is disposed between the first auxiliary busbar and the first busbar, with one end of the first connecting post connected to the first auxiliary busbar and the other end of the first connecting post connected to the first busbar.

[0008] With this configuration, the first auxiliary busbar receives electrical signals and feeds them into the first busbar through the first connecting post, causing the piezoelectric material layer near the first insertion finger to vibrate and generate sound waves. The sound velocity of the piezoelectric material layer corresponding to the first auxiliary busbar is different from the sound velocity of the piezoelectric material layer between the first auxiliary busbar and the first busbar. The sound waves can be reflected on the piezoelectric material layer corresponding to the first auxiliary busbar to further prevent sound wave leakage.

[0009] In some embodiments that may include the above embodiments, the transducer further includes a second auxiliary busbar and a second connecting post. The second auxiliary busbar is located on the surface of the piezoelectric material layer and is disposed on the side of the second busbar away from the first busbar. The second auxiliary busbar and the second busbar are spaced apart. The second connecting post is disposed between the second auxiliary busbar and the second busbar. One end of the second connecting post is connected to the second auxiliary busbar, and the other end of the second connecting post is connected to the second busbar.

[0010] With this configuration, the second auxiliary busbar receives electrical signals and feeds them into the second busbar through the second connecting post, causing the piezoelectric material layer near the second insertion finger to vibrate and generate sound waves. The sound velocity of the piezoelectric material layer corresponding to the second auxiliary busbar is different from the sound velocity of the piezoelectric material layer between the second auxiliary busbar and the second busbar. The sound waves can be reflected on the piezoelectric material layer corresponding to the second auxiliary busbar to further prevent sound wave leakage.

[0011] In some embodiments that may include the above-described embodiments, the transducer further includes a second dummy finger, which is disposed between the first busbar and the second busbar, and is connected to the first busbar. This arrangement can reduce the sound velocity of the portion of the piezoelectric material layer corresponding to the second dummy finger, causing sound waves on the piezoelectric material layer corresponding to the transmission channel to be reflected at the location of the second dummy finger, thus preventing sound waves from leaking out of the first busbar.

[0012] In some embodiments that may include the above-described embodiments, the transducer further includes a first auxiliary dummy finger, which is disposed between the first busbar and the second busbar. The first insertion finger is connected to the first busbar via the first auxiliary dummy finger. This configuration can reduce the sound velocity of the piezoelectric material layer corresponding to the first auxiliary dummy finger, causing the sound waves on the piezoelectric material layer corresponding to the transmission channel to be reflected at the location of the first auxiliary dummy finger, thus preventing the sound waves from leaking out of the first busbar.

[0013] In some embodiments that may include the above-described embodiments, the width of the first auxiliary dummy finger is greater than the width of the first insert finger along the length of the first busbar. This configuration can further reduce the sound velocity of the portion of the piezoelectric material layer corresponding to the first auxiliary dummy finger, further preventing sound waves from leaking out of the first busbar.

[0014] In some embodiments that may include the above-described embodiments, the transducer further includes a second auxiliary pseudofinger disposed between the first auxiliary busbar and the first busbar, and the first connecting post is connected to the first busbar via the second auxiliary pseudofinger. This configuration allows the second auxiliary pseudofinger to further increase the density of the side of the first busbar facing away from the second busbar, 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 clutter formed by the coupling between this acoustic wave and the acoustic wave corresponding to the second resonance, and improving communication performance. Furthermore, the sound velocity in the piezoelectric material layer where the second auxiliary pseudofinger is located is lower than the sound velocity in the piezoelectric material layer on the side of the first pseudofinger facing away from the first busbar. 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 auxiliary pseudofinger, 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 further improving communication performance.

[0015] In some embodiments that may include the above-described embodiments, the width of the second auxiliary dummy finger is greater than the width of the first connecting post along a direction parallel to the piezoelectric material layer and parallel to the length of the first busbar. This configuration increases the mass of the second auxiliary dummy finger, 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.

[0016] In some embodiments that may include the above-described embodiments, the transducer further includes a third auxiliary pseudo-finger, which is disposed between the first auxiliary busbar and the first busbar, and connected to the first auxiliary busbar; the third auxiliary pseudo-finger is spaced apart from the first pseudo-finger. This arrangement can reduce the sound velocity of the piezoelectric material layer corresponding to the third auxiliary pseudo-finger, allowing sound waves to be scattered on the piezoelectric material layer corresponding to the third auxiliary pseudo-finger, thus preventing sound wave leakage. Furthermore, since the sound waves with frequencies higher than the anti-resonance point of the first resonance (sound waves corresponding to the Rayleigh transverse mode) and the sound waves corresponding to the second resonance (sound waves corresponding to the SH mode) are both scattered on the piezoelectric material layer corresponding to the third auxiliary pseudo-finger, 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.

[0017] In some embodiments that may include the above-described embodiments, the transducer further includes a fourth auxiliary pseudo-finger, which is disposed between the first auxiliary busbar and the first busbar, with the fourth auxiliary pseudo-finger spaced apart from both the first auxiliary busbar and the first busbar. This arrangement reduces the sound velocity in the piezoelectric material layer corresponding to the fourth auxiliary pseudo-finger, allowing sound waves to be scattered on the piezoelectric material layer, thus preventing sound 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 corresponding to the fourth auxiliary pseudo-finger, 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.

[0018] In some embodiments that may include the above embodiments, the length directions of the first busbar and the second busbar are parallel, and the distance between the first busbar and the first auxiliary busbar is 1.3L1-2.8L1; along a direction parallel to the piezoelectric material layer and perpendicular to the length of the first busbar, the thickness of the first dummy finger is 0.1L1-0.4L1, where L1 is the shortest distance between the center line of the first dummy finger and the center line of the second dummy finger.

[0019] With the above configuration, the thickness of the first dummy finger is moderate, ensuring sufficient thickness along the direction perpendicular to the length of the first busbar. This allows the first dummy finger 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 cause scattering 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) on the piezoelectric material layer near the first dummy finger. Simultaneously, it avoids the first dummy finger from being too thick.

[0020] In some embodiments that may include the above-described embodiments, the width of the first dummy finger along the length of the first busbar is greater than or equal to 0.4L1, where L1 is the shortest distance between the center lines of the first and second dummy fingers. This configuration ensures that the first dummy finger has sufficient width along the direction parallel to the length of the first busbar, enabling it to suppress the formation of sound waves with frequencies higher than the anti-resonance point of the first resonance (sound waves corresponding to the Rayleigh transverse mode), while also preventing the width of the first dummy finger from becoming excessive.

[0021] In some embodiments that may include the above embodiments, the width of the first dummy finger is less than or equal to 0.8L1 along the length of the first busbar; the first dummy finger has a first midpoint and the first insertion finger has a second midpoint along the length of the first busbar, and the distance between the first midpoint and the second midpoint is 0.5L1-1.5L1. This configuration avoids the first dummy finger from being too wide, thereby preventing sound waves from propagating outward through the first dummy finger, i.e., preventing sound waves from leaking outward from the first dummy finger.

[0022] In some embodiments that may include the above-described embodiments, the transducer further includes a third pseudo-finger, which is disposed on the side of the second busbar facing away from the transmission channel. The third pseudo-finger is connected to the second busbar. Through this configuration, the third pseudo-finger can increase the density of the second busbar on the side facing 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), thus reducing clutter formed by the coupling between this acoustic wave and the acoustic wave corresponding to the second resonance, and improving communication performance. Furthermore, the sound velocity in the piezoelectric material layer where the third pseudo-finger is located is lower than the sound velocity in the piezoelectric material layer on the side of the third pseudo-finger facing 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 third 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 further improving communication performance.

[0023] In some embodiments that may include the above-described embodiments, the transducer further includes a fourth pseudo-finger, which is disposed between the first busbar and the second busbar and connected to the second busbar; that is, the fourth pseudo-finger is disposed on the piezoelectric material layer and connected to the second busbar. This arrangement can reduce the sound velocity of the portion of the piezoelectric material layer corresponding to the fourth pseudo-finger, causing the sound waves on the piezoelectric material layer corresponding to the transmission channel to be reflected at the location of the fourth pseudo-finger, thus preventing sound waves from leaking out of the second busbar.

[0024] In some embodiments that may include the above-described embodiments, the transducer further includes a fifth auxiliary dummy finger, which is disposed between the first busbar and the second busbar. The second insertion finger is connected to the second busbar via the fifth auxiliary dummy finger. This configuration can reduce the sound velocity of the piezoelectric material layer corresponding to the fifth auxiliary dummy finger, causing the sound waves on the piezoelectric material layer corresponding to the transmission channel to be reflected at the location of the fifth auxiliary dummy finger, thus preventing the sound waves from leaking out of the second busbar.

[0025] In some embodiments that may include the above-described embodiments, the transducer further includes a sixth auxiliary pseudofinger, which is disposed between the second auxiliary busbar and the second busbar. The second connecting post is connected to the second busbar via the sixth auxiliary pseudofinger. This configuration allows the sixth auxiliary pseudofinger to further increase the density of the second busbar on the side facing away from the transmission channel, 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 clutter formed by the coupling between this acoustic wave and the acoustic wave corresponding to the second resonance, and improving communication performance. Furthermore, the sound velocity in the piezoelectric material layer where the sixth auxiliary pseudofinger is located is lower than the sound velocity in the piezoelectric material layer on the side facing away from the transmission channel of the third pseudofinger. 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 sixth auxiliary pseudofinger, 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.

[0026] In some embodiments that may include the above-described embodiments, the transducer further includes a seventh auxiliary pseudo-finger, which is disposed between the second auxiliary busbar and the second busbar, and connected to the second auxiliary busbar; the seventh auxiliary pseudo-finger is spaced apart from the third pseudo-finger. This arrangement can reduce the sound velocity of the piezoelectric material layer corresponding to the seventh auxiliary pseudo-finger, allowing sound waves to be scattered on the piezoelectric material layer corresponding to the seventh auxiliary pseudo-finger, thus preventing sound wave leakage. Furthermore, since the sound waves with frequencies higher than the anti-resonance point of the first resonance (sound waves corresponding to the Rayleigh transverse mode) and the sound waves corresponding to the second resonance (sound waves corresponding to the SH mode) are both scattered on the piezoelectric material layer corresponding to the seventh auxiliary pseudo-finger, 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.

[0027] In some embodiments that may include the above-described embodiments, the transducer further includes an eighth auxiliary pseudo-finger, which is disposed between the second auxiliary busbar and the second busbar, with the eighth auxiliary pseudo-finger spaced apart from both the second auxiliary busbar and the second busbar. This arrangement reduces the sound velocity in the piezoelectric material layer corresponding to the eighth auxiliary pseudo-finger, allowing sound waves to be scattered on the piezoelectric material layer, thus preventing sound 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 corresponding to the eighth auxiliary pseudo-finger, 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.

[0028] Secondly, embodiments of this application also provide a filter, including a plurality of surface acoustic wave resonators, wherein at least one is a surface acoustic wave resonator as described above, and at least two of the plurality of surface acoustic wave resonators are connected in series or in parallel.

[0029] The filters in this application include the surface acoustic wave resonators in any of the above embodiments, so both can solve the same technical problem and achieve the same technical effect.

[0030] Thirdly, embodiments of this application also provide a communication chip, including: a radio frequency front-end circuit and a filter as described above, wherein the radio frequency front-end circuit includes a power amplifier and / or a low noise amplifier, and the radio frequency front-end circuit is coupled to the filter.

[0031] 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.

[0032] Fourthly, 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.

[0033] 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

[0034] Figure 1 is a schematic diagram of the structure of the electronic device provided in an embodiment of this application;

[0035] Figure 2 is a schematic diagram of the structure of the communication chip provided in an embodiment of this application;

[0036] Figure 3 is a top view of the surface acoustic wave resonator provided in an embodiment of this application;

[0037] Figure 4 is a cross-sectional view along direction AA in Figure 3;

[0038] Figure 5 shows the relationship between admittance and frequency of a transducer without a first pseudo-finger.

[0039] Figure 6 shows the relationship between admittance and frequency of a transducer with a first pseudo-finger.

[0040] Figure 7 is a top view of the surface acoustic wave resonator provided in the embodiment of this application;

[0041] Figure 8 is a top view of the surface acoustic wave resonator provided in the embodiment of this application;

[0042] Figure 9 is a top view of the surface acoustic wave resonator provided in the embodiment of this application;

[0043] Figure 10 is a top view of the surface acoustic wave resonator provided in the embodiment of this application;

[0044] Figure 11 is a top view of the surface acoustic wave resonator provided in the embodiment of this application;

[0045] Figure 12 is a top view of the surface acoustic wave resonator provided in the embodiment of this application.

[0046] Figure reference numerals: 11: Frame; 12: Display panel; 13: Back cover; 14: Motherboard; 15: Antenna; 20: Communication chip; 21: RF front-end circuit; 22: Filter; 23: Power amplifier; 24: Low noise amplifier; 30: Surface acoustic wave resonator; 31: Piezoelectric material layer; 32: Transducer; 35: Substrate; 321: First busbar; 322: Second busbar; 323: Transmission channel; 324: First interpolation finger; 325: Second interpolation finger; 326: First... 327: First auxiliary busbar; 328: First connecting post; 329: Second auxiliary busbar; 330: Second connecting post; 331: Second pseudo-finger; 332: Third pseudo-finger; 333: Expansion section; 334: First auxiliary pseudo-finger; 335: Second auxiliary pseudo-finger; 336: Third auxiliary pseudo-finger; 337: Fourth auxiliary pseudo-finger; 338: Fourth pseudo-finger; 339: Fifth auxiliary pseudo-finger; 340: Sixth auxiliary pseudo-finger; 341: Seventh auxiliary pseudo-finger; 342: Eighth auxiliary pseudo-finger. Detailed Implementation

[0047] 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.

[0048] 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.

[0049] 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.

[0050] This application provides an electronic device, which may include mobile phones, tablets, laptops, smart bracelets, smartwatches, and other devices. As shown in Figure 1, 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.

[0051] 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.

[0052] 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.

[0053] Referring to Figure 2, in some embodiments, the communication chip 20 may include a radio frequency front-end circuit 21 and a filter 22. The radio frequency front-end circuit 21 is coupled to the filter 22, and the filter 22 is coupled to the antenna 15 shown in Figure 1. The filter 22 can realize the coupling between the radio frequency front-end circuit 21 and the antenna 15. At the same time, the filter 22 can remove signals that are not needed for communication, thereby avoiding interference and improving communication quality.

[0054] In some implementations, the RF front-end circuit 21 may include a power amplifier 23. The signal from the signal source passes through the power amplifier 23 and then enters a filter 22. The filter 22 then feeds the signal into the antenna 15 for transmission. The signal source may include a modulator or other device capable of outputting RF signals. The power amplifier 23 is used to increase the signal power to increase the gain of the antenna 15, thereby increasing the transmission distance. The filter 22 can filter out signals outside the communication frequency band.

[0055] In some implementations, the RF front-end circuit 21 may include a low-noise amplifier 24. After the antenna 15 receives electromagnetic signals from the space, it generates an electrical signal. This signal passes through a filter 22 and then enters the low-noise amplifier 24. The signal output from the low-noise amplifier 24 can be transmitted to a demodulator to achieve signal reception. The filter 22 is used to filter out signals outside the communication frequency band, and the low-noise amplifier 24 can improve the signal-to-noise ratio and the accuracy of the received signal.

[0056] In other implementations, the radio frequency front-end circuit 21 may include a power amplifier 23 and a low-noise amplifier 24. In this case, the radio frequency front-end circuit 21 can transmit and receive signals, thereby improving the communication performance of the electronic device.

[0057] In the above implementation, the radio frequency front-end circuit 21 and the filter 22 can be packaged on the same packaging substrate, which can improve the structural compactness of the communication chip 20, and also facilitate the manufacturing and installation of the communication chip 20.

[0058] In this embodiment, the filter 22 includes multiple surface acoustic wave (SAW) resonators, at least two of which are connected in series or parallel. Referring to Figures 3 and 4, at least one SAW 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 4). When the transducer 32 receives an electrical signal, it drives the surface of the piezoelectric material layer 31 to vibrate, generating sound waves (SAWs). These sound waves propagate along the surface, converting the electrical signal into a mechanical vibration signal (sound wave). When the sound wave reaches the end of the piezoelectric material layer 31, only sound waves that meet 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.

[0059] 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, the scattering and absorption of energy in the piezoelectric material layer 31 can be reduced, thereby improving the quality factor (Q value) of the surface acoustic wave resonator 30.

[0060] Referring again to Figures 3 and 4, in some implementations, 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, horizontal direction in Figure 3) are parallel. The first busbar 321 and the second busbar 322 are spaced apart along their width direction. The width direction is parallel to the piezoelectric material layer 31 and perpendicular to the extension directions of the first busbar 321 and the second busbar 322 (vertical direction in Figure 3). A transmission channel 323 is formed between the first busbar 321 and the second busbar 322, allowing sound waves to propagate near the surface of the piezoelectric material layer 31 corresponding to this transmission channel 323. It can be 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 Figure 3.

[0061] The transducer 32 also includes a first interposer 324 and a second interposer 325, which are disposed on the surface of the piezoelectric material layer 31 and located within the transmission channel 323, that is, between the first busbar 321 and the second busbar 322. The first interposer 324 and the second interposer 325 extend on the piezoelectric material layer 31, and their extension directions (length directions) are parallel. The first interposer 324 and the second interposer 325 are spaced apart along their width direction, which is perpendicular to the extension direction of the first interposer 324 and the second interposer 325. The extension direction of the first insert finger 324 can be perpendicular to the extension direction of the first busbar 321, or there can be other angles between the extension direction of the first insert finger 324 and the extension direction of the first busbar 321. The end of the first insert finger 324 near the first busbar 321 is connected to the first busbar 321, and the end of the first insert finger 324 near the second busbar 322 is spaced apart from the second busbar 322. Similarly, the extension direction of the second insert finger 325 can be perpendicular to the extension direction of the second busbar 322, or there can be other angles between the extension direction of the second insert finger 325 and the extension direction of the second busbar 322. The end of the second insert finger 325 near the second busbar 322 is connected to the second busbar 322, and the end of the second insert finger 325 near the first busbar 321 is spaced apart from the first busbar 321. The first busbar 321 and the second busbar 322 are used to receive radio frequency signals. The first busbar 321 feeds the signal into the first interposer 324, and the second busbar 322 feeds the signal into the second interposer 325, so that the piezoelectric material layer 31 near the first interposer 324 and the second interposer 325 vibrates, thereby forming sound waves.

[0062] In some implementations, there are multiple first interposers 324 and multiple second interposers 325. These multiple first interposers 324 and multiple second interposers 325 are alternately arranged along the extension direction of the first busbar 321. That is, a second interposer 325 is positioned between two adjacent first interposers 324, and a first interposer 324 is positioned between two connected second interposers 325. Thus, the first busbar 321 can simultaneously feed power to each first interposer 324, and the second busbar 322 can simultaneously feed power to each second interposer 325. The piezoelectric material layer 31 near each first interposer 324 and second interposer 325 can vibrate to generate sound waves, thereby increasing the power of the surface acoustic wave resonator 30.

[0063] In some implementations, the first interposer 324 can be integrated with the first busbar 321. Correspondingly, the first interposer 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 interposer 324 and the first busbar 321. Similarly, the second busbar 322 and the second interposer 325 can also be integrated. The fabrication methods for the second busbar 322 and the second interposer 325 are roughly similar to those for the first interposer 324 and the first busbar 321, and will not be elaborated further here.

[0064] In some implementations, the first interpolation finger 324, the first bus bar 321, the second interpolation finger 325, and the second bus bar 322 can be formed simultaneously using the same manufacturing method, which reduces the manufacturing difficulty of the surface acoustic wave resonator 30 and also improves the manufacturing efficiency of the surface acoustic wave resonator 30.

[0065] In some embodiments, the first interposer 324 may include multiple metal layers stacked on the piezoelectric material layer 31. That is, multiple metal layers are stacked on the piezoelectric material layer 31 to form the first interposer 324. For example, the materials of the metal layers may include platinum (Pt), molybdenum (Mo), tungsten (W), aluminum (Al), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), copper (Cu), tantalum (Ta), osmium (Os), iridium (Ir), gold (Au), etc. Adjacent metal layers may be made of different materials. Since different metals have different densities, the overall density of the first interposer 324 can be adjusted by reasonably selecting the materials of each metal layer. Similarly, the structure and material of the second interposer 325 may be substantially similar to those of the first interposer 324, and will not be described in detail here.

[0066] In some examples, both the first interdigitator 324 and the second interdigitator 325 include at least two metal layers. One metal layer can be made of aluminum, and the other metal layer can be made of platinum, molybdenum, or tungsten to ensure a high density of the first interdigitator 324 and the second interdigitator 325. It is understood that the surface acoustic wave resonator 30 satisfies f = v / (2λ), where f is the resonant frequency of the sound wave generated by the surface acoustic wave 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. At a constant resonant frequency, reducing the sound speed can reduce the wavelength of the sound. In the transducer 32, twice the shortest distance L1 between the center line of the first interdigitator 324 (the dashed line in Figure 3) and the center line of the second interdigitator 325 (the dashed line in Figure 3) is equal to the wavelength. Furthermore, increasing the density of the first interdigitator 324 and the second interdigitator 325 can reduce the sound speed on the surface of the piezoelectric material layer 31. Therefore, by increasing the density of the first interdigitation finger 324 and the second interdigitation finger 325, the wavelength of the sound wave can be reduced, thereby reducing the distance between the first interdigitation finger 324 and the second interdigitation finger 325. This allows for a reduction in the volume of the transducer 32 and the surface acoustic wave resonator 30, facilitating miniaturization. For example, the density of the first interdigitation finger 324 and the second interdigitation finger 325 can be greater than or equal to 8900 kg / m³.

[0067] Referring again to Figure 3, in this embodiment of the application, when the surface acoustic wave 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 5. In Figure 5, the solid line represents the absolute value of the admittance, and the dashed line represents the real part of the admittance. 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 in a direction approximately parallel to the length of the first busbar 321 near the surface of the piezoelectric material layer 31 corresponding to the transmission channel 323.

[0068] In some examples, the resonant frequency of the first resonance is lower than that of the second resonance. The first resonance includes a resonant point and an anti-resonant point. While the transducer 32 generates the acoustic wave corresponding to the first resonance, it also generates an acoustic wave with a frequency higher than the anti-resonant point on the side of the first busbar 321 away from the transmission channel 323 (as shown in region M in Figure 5, the acoustic wave corresponding to the Rayleigh transverse mode). This acoustic wave will couple (acoustic wave interference) with the acoustic wave corresponding to the second resonance (the acoustic wave corresponding to the SH mode) that leaks to the side of the first busbar 321 away from the transmission channel 323, thereby forming clutter (as shown in region N in Figure 5). This clutter will form an interference signal and affect the communication performance.

[0069] Referring again to Figure 3, in this embodiment, the transducer 32 further includes a first pseudo-finger 326. The first pseudo-finger 326 is disposed on the side of the first busbar 321 opposite to the second busbar 322. That is, the first pseudo-finger 326 is disposed on the piezoelectric material layer 31 and is located outside the transmission channel 323. The first pseudo-finger 326 is connected to the first busbar 321, which can be understood as the first pseudo-finger 326 contacting the first busbar 321. For example, the first pseudo-finger 326 and the first busbar 321 can be an integral structure, or the first pseudo-finger 326 and the first busbar 321 can be connected by welding or other means.

[0070] Through the above configuration, the first pseudo-finger 326 can increase the density of the side of the first busbar 321 facing away from the second busbar 322, thereby preventing the formation of sound waves with frequencies higher than the anti-resonance point of the first resonance (sound waves corresponding to the Rayleigh transverse mode), reducing noise generated by the coupling between this sound wave and the sound wave corresponding to the second resonance, and improving communication performance. Furthermore, the increased density of the side of the first busbar 321 facing away from the second busbar 322 causes the sound velocity of the piezoelectric material layer 31 where the first pseudo-finger 326 is located to be lower than the sound velocity of the piezoelectric material layer 31 on the side of the first pseudo-finger 326 facing away from the transmission channel 323. Therefore, the sound waves with frequencies higher than the anti-resonance point of the first resonance (sound waves corresponding to the Rayleigh transverse mode) and the sound waves corresponding to the second resonance (sound waves corresponding to the SH mode) will be scattered (e.g., reflected and / or refracted) on the piezoelectric material layer 31 near the first pseudo-finger 326, preventing the 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, further reducing noise and improving communication performance.

[0071] In Figure 3, the broken line K on the left represents the sound velocity of the piezoelectric material layer 31 at different positions of the transducer 32. The closer the line segment is to the transducer 32, the lower the sound velocity of the piezoelectric material layer 31 at that position. As shown in Figure 3, the sound velocity of the piezoelectric material layer 31 in the region where the first pseudo-finger 326 is located is different from that in the adjacent regions. 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 scattered on the piezoelectric material layer 31 near the first pseudo-finger 326 to reduce coupling.

[0072] Please refer to Figures 5 and 6. Figure 5 shows the admittance versus frequency relationship of a transducer without the first pseudo-finger, and Figure 6 shows the admittance versus frequency relationship of a transducer with the first pseudo-finger. In the figures, the solid line represents the absolute value of the admittance, and the dashed line represents the real part of the admittance. Comparing Figures 5 and 6, it can be seen that setting the first pseudo-finger 326 reduces the noise generated by the coupling of sound waves with frequencies higher than the anti-resonance point of the first resonance (as shown in region M in Figures 5 and 6) and the sound waves corresponding to the second resonance (as shown in region N in Figures 5 and 6). In addition, since the first pseudo-finger 326 can reflect the sound waves corresponding to the second resonance to the piezoelectric material layer 31 corresponding to the transmission channel 323, setting the first pseudo-finger 326 makes the imaginary part curve of the admittance between the resonant point and the anti-resonance point of the second resonance smoother (as shown in region P in Figures 5 and 6), that is, it reduces the sound waves corresponding to the SH transverse mode.

[0073] Referring again to Figure 3, expansion portions 333 are provided at both ends of the first insert 324 near the first busbar 321 and near the second busbar 322. Along the width direction perpendicular to the length of the first busbar 321, the dimensions of the expansion portions 333 are larger than those at other locations on the first insert 324. This results in the sound velocity of the piezoelectric material layer 31 corresponding to the expansion portion 333 being lower than the sound velocity of the piezoelectric material layers 31 corresponding to the first inserts 324 on both sides. Consequently, sound waves can be reflected in this region, preventing sound waves from leaking to the outside of the first busbar 321 and the second busbar 322 (the side away from the transmission channel 323). Similarly, expansion portions 333 are also provided at both ends of the second insert 325 near the first busbar 321 and the second insert 325 near the second busbar 322, allowing sound waves to be reflected in this region, further preventing sound waves from leaking to the outside of the first busbar 321 and the second busbar 322.

[0074] Referring again to Figure 3, in some embodiments, the transducer 32 further includes a first auxiliary busbar 327 and a first connecting post 328. The first auxiliary busbar 327 is located on the surface of the piezoelectric material layer 31 and is disposed on the side of the first busbar 321 opposite to the second busbar 322. The first auxiliary busbar 327 and the first busbar 321 are spaced apart. The first connecting post 328 is disposed between the first auxiliary busbar 327 and the first busbar 321. One end of the first connecting post 328 is connected to the first auxiliary busbar 327, and the other end of the first connecting post 328 is connected to the first busbar 321. The first auxiliary busbar 327 receives electrical signals and feeds them into the first busbar 321 through the first connecting post 328, thereby causing the piezoelectric material layer 31 near the first interdigitator 324 to vibrate and generate sound waves. The sound velocity of the piezoelectric material layer 31 corresponding to the first auxiliary busbar 327 is different from the sound velocity of the piezoelectric material layer 31 between the first auxiliary busbar 327 and the first busbar 321. The sound wave can be reflected on the piezoelectric material layer 31 corresponding to the first auxiliary busbar 327 to further prevent sound wave leakage.

[0075] In some implementations, the transducer 32 further includes a second auxiliary busbar 329 and a second connecting post 330. The second auxiliary busbar 329 is located on the surface of the piezoelectric material layer 31 and is disposed on the side of the second busbar 322 opposite to the first busbar 321. The second auxiliary busbar 329 and the second busbar 322 are spaced apart. The second connecting post 330 is disposed between the second auxiliary busbar 329 and the second busbar 322. One end of the second connecting post 330 is connected to the second auxiliary busbar 329, and the other end of the second connecting post 330 is connected to the second busbar 322. The second auxiliary busbar 329 receives electrical signals and feeds them into the second busbar 322 through the second connecting post 330, thereby causing the piezoelectric material layer 31 near the second interdigitator 325 to vibrate and generate sound waves. The sound velocity of the piezoelectric material layer 31 corresponding to the second auxiliary busbar 329 is different from the sound velocity of the piezoelectric material layer 31 between the second auxiliary busbar 329 and the second busbar 322. The sound wave can be reflected on the piezoelectric material layer 31 corresponding to the second auxiliary busbar 329 to further prevent sound wave leakage.

[0076] Referring to Figure 7, in some embodiments, the transducer 32 further includes a second pseudo-finger 331, which is disposed between the second busbar 322 and the first busbar 321, and is connected to the first busbar 321; that is, the second pseudo-finger 331 is disposed on the piezoelectric material layer 31 and is connected to 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 331, 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 331, thus preventing sound waves from leaking out of the first busbar 321.

[0077] In some examples, the second dummy finger 331 can be positioned between the second insert finger 325 and the first busbar 321, and the second dummy finger 331 and the second insert finger 325 can be spaced apart. Along a direction perpendicular to the length of the first busbar 321, the projections of the second dummy finger 331 and the second insert finger 325 onto the first busbar 321 can at least partially overlap, although the projections of the second dummy finger 331 and the second insert finger 325 onto the first busbar 321 can also be spaced apart.

[0078] In some examples, along a direction perpendicular to the length of the first busbar 321, the projections of the first dummy finger 326 and the second dummy finger 325 onto the first busbar 321 can at least partially overlap. Of course, the projections of the first dummy finger 326 and the second dummy finger 325 onto the first busbar 321 can also be spaced apart. Along a direction perpendicular to the length of the first busbar 321, the projections of the first dummy finger 326 and the second dummy finger 331 onto the first busbar 321 can at least partially overlap.

[0079] Referring to Figure 7, in some implementations, along a direction parallel to the piezoelectric material layer 31 and parallel to the length of the first busbar 321, the first dummy finger 326 has a first midpoint a, and the first interdigitated finger 324 has a second midpoint b. The distance L2 between the first midpoint a and the second midpoint b is 0.25λ-0.75λ (0.5L1-1.5L1 in Figure 3). For example, L2 can be 0.25λ, 0.5λ, 0.75λ, etc. In the implementation where the distance between the first midpoint a and the second midpoint b is 0.5λ, the distance between the first midpoint a of two adjacent first dummy fingers 326 is λ, and the distance between the second midpoint b of two adjacent second dummy fingers 331 is λ. Along a direction parallel to the piezoelectric material layer 31 and perpendicular to the length of the first busbar 321, the width L3 of the first busbar 321 is 0.1λ-0.5λ (e.g., 0.1λ, 0.15λ, 0.5λ, etc.), and the distance between the first busbar 321 and the first auxiliary busbar 327 is 0.65λ-1.4λ (1.3L1-2.8L1 in Figure 3). For example, this distance can be 0.65λ, λ, 1.4λ, etc., along the direction parallel to the piezoelectric material layer 31 and perpendicular to the length of the first busbar 321. The thickness L4 of the first pseudo-finger 326, which runs along the piezoelectric material layer 31 and is perpendicular to the length of the first busbar 321, is 0.05λ-0.2λ (0.1L1-0.4L1 in Figure 3). For example, L4 can be 0.05λ, 0.1λ, 0.2λ, etc. Correspondingly, the distance L5 between the first pseudo-finger 326 and the first auxiliary busbar 327 is 0.6λ-1.2λ (such as 0.6λ, 0.9λ, 1.2λ, etc.).

[0080] With the above configuration, the thickness of the first dummy finger 326 is moderate, ensuring sufficient thickness along the direction perpendicular to the length of the first busbar 321. This allows the first dummy finger 326 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 cause scattering 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) on the piezoelectric material layer 31 near the first dummy finger 326. Simultaneously, it also avoids the first dummy finger 326 being excessively thick.

[0081] In the above implementation, along the direction parallel to the piezoelectric material layer 31 and perpendicular to the length of the first busbar 321, the thickness L6 of the second dummy finger 331 is 0.05λ-0.2λ (e.g., 0.05λ, 0.1λ, 0.2λ, etc.), and the distance L7 between the second dummy finger 331 and the second intercalation finger 325 is 0.05λ-0.2λ (e.g., 0.05λ, 0.1λ, 0.2λ, etc.). This setting ensures that the thickness of the second dummy finger 331 is moderate, guaranteeing sufficient thickness along the direction perpendicular to the length of the first busbar 321 to allow sound waves to be scattered on the piezoelectric material layer 31 near the second dummy finger 331, while also preventing the second dummy finger 331 from being too thick. The length L8 of the expansion portion 333 in the direction perpendicular to the length of the first busbar 321 can be 0.6λ-1.2λ (such as 0.6λ, 0.9λ, 1.2λ, etc.) so that the expansion portion 333 has sufficient length to prevent leakage from the area where the first busbar 321 is located.

[0082] In the implementation where the distance between the first midpoint a and the second midpoint b is 0.25λ-0.75λ, the width L9 of the first pseudo-finger 326 is greater than or equal to 0.2λ (greater than or equal to 0.4L1 in Figure 3) along a direction parallel to the piezoelectric material layer 31 and parallel to the length of the first busbar 321. For example, L9 can be 0.2λ, 0.325λ, etc. This setting ensures that the first pseudo-finger 326 has a sufficient width along the direction parallel to the length of the first busbar 321, so that the first pseudo-finger 326 can suppress the formation of sound waves with frequencies higher than the anti-resonance point of the first resonance (sound waves corresponding to the Rayleigh transverse mode), while also avoiding the first pseudo-finger 326 being too wide.

[0083] In the above implementation, along the direction parallel to the piezoelectric material layer 31 and parallel to the length of the first busbar 321, the width L9 of the first dummy finger 326 is less than or equal to 0.4λ (less than or equal to 0.8L1 in Figure 3). For example, L9 can be 0.4λ, 0.325λ, etc. This setting can prevent the width of the first dummy finger 326 from being too large, thereby preventing sound waves from propagating outward through the first dummy finger 326, that is, preventing sound waves from leaking outward from the first dummy finger 326.

[0084] Referring again to Figures 3 and 7, in some embodiments, the transducer 32 further includes a third pseudo-finger 332. The third pseudo-finger 332 is disposed on the side of the second busbar 322 opposite to the first busbar 321. That is, the third pseudo-finger 332 is disposed on the piezoelectric material layer 31 and is located outside the transmission channel 323. The connection between the third pseudo-finger 332 and the second busbar 322 can be understood as the third pseudo-finger 332 being in contact with the second busbar 322. For example, the third pseudo-finger 332 and the second busbar 322 can be an integral structure, or the third pseudo-finger 332 and the second busbar 322 can be connected by welding or other means.

[0085] Through the above configuration, the third pseudo-finger 332 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 third pseudo-finger 332 is located is lower than the sound velocity of the piezoelectric material layer 31 on the side of the third pseudo-finger 332 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 third pseudo-finger 332, 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.

[0086] Referring again to Figure 7, in the above implementation, the transducer 32 further includes a fourth pseudo-finger 338. The fourth pseudo-finger 338 is disposed between the second busbar 322 and the first busbar 321, and is connected to the second busbar 322. That is, the fourth pseudo-finger 338 is disposed on the piezoelectric material layer 31, and is connected to the second busbar 322. This arrangement can reduce the sound velocity of the portion of the piezoelectric material layer 31 corresponding to the fourth pseudo-finger 338, causing the sound waves on the piezoelectric material layer 31 corresponding to the transmission channel 323 to be reflected at the location of the fourth pseudo-finger 338, preventing the sound waves from leaking out of the second busbar 322.

[0087] In some examples, the fourth dummy finger 338 can be positioned between the first insert finger 324 and the second busbar 322, and the fourth dummy finger 338 and the first insert finger 324 can be spaced apart. Along a direction perpendicular to the length of the second busbar 322, the projections of the fourth dummy finger 338 and the first insert finger 324 onto the second busbar 322 can at least partially overlap; however, the projections of the fourth dummy finger 338 and the first insert finger 324 onto the second busbar 322 can also be spaced apart.

[0088] In some examples, along a direction perpendicular to the length of the second busbar 322, the projections of the third spur finger 332 and the first insert finger 324 onto the second busbar 322 can at least partially overlap; of course, the projections of the third spur finger 332 and the first insert finger 324 onto the second busbar 322 can also be spaced apart. Along a direction perpendicular to the length of the second busbar 322, the projections of the third spur finger 332 and the fourth spur finger 338 onto the first busbar 321 can at least partially overlap.

[0089] Referring to Figure 8, in this embodiment, the transducer 32 further includes a first auxiliary pseudo-finger 334, which is disposed between the second busbar 322 and the first busbar 321. The first insertion finger 324 is connected to the first busbar 321 via the first auxiliary pseudo-finger 334. This configuration reduces the sound velocity of a portion of the piezoelectric material layer 31 corresponding to the first auxiliary pseudo-finger 334, causing 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 334, thus preventing sound waves from leaking out of the first busbar 321.

[0090] For example, along a direction parallel to the piezoelectric material layer 31 and parallel to the length of the first busbar 321, the width of the first auxiliary dummy finger 334 is greater than the width of the first insert 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 334, and further prevent sound waves from leaking out of the first busbar 321.

[0091] It is understandable that the first auxiliary pseudofinger 334 can be integrated with the first insert finger 324, meaning that the first auxiliary pseudofinger 334 and the first insert finger 324 can be formed simultaneously using the same process. The first auxiliary pseudofinger 334 and the first insert finger 324 can be made of the same material, but their widths are different, resulting in a lower sound velocity in the piezoelectric material layer 31 corresponding to the first auxiliary pseudofinger 334, which in turn causes sound waves to be reflected.

[0092] Referring again to Figure 8, in the implementation of transducer 32 including a first auxiliary busbar 327 and a first connecting post 328, transducer 32 further includes a second auxiliary dummy finger 335. The second auxiliary dummy finger 335 is disposed between the first auxiliary busbar 327 and the first busbar 321, and the first connecting post 328 is connected to the first busbar 321 through the second auxiliary dummy finger 335. With this configuration, the second auxiliary dummy finger 335 can further increase the density of the side of the first busbar 321 facing away from the second busbar 322, further preventing the formation of sound waves with frequencies higher than the anti-resonance point of the first resonance (sound waves corresponding to the Rayleigh transverse mode), thereby reducing the noise formed by the coupling between this sound wave and the sound 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 335 is located is less than the sound velocity of the piezoelectric material layer 31 on the side of the first pseudo-finger 326 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 335 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.

[0093] For example, along a direction parallel to the piezoelectric material layer 31 and parallel to the length of the first busbar 321, the width of the second auxiliary dummy finger 335 is greater than the width of the first connecting post 328. This configuration increases the mass of the second auxiliary dummy finger 335, 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.

[0094] Referring to Figures 9 and 10, in some embodiments, the transducer 32 further includes a third auxiliary pseudo-finger 336, which is disposed between the first auxiliary busbar 327 and the first busbar 321, and is connected to the first auxiliary busbar 327; the third auxiliary pseudo-finger 336 is spaced apart from the first pseudo-finger 326. This arrangement can reduce the sound velocity of the piezoelectric material layer 31 corresponding to the third auxiliary pseudo-finger 336, so that the sound wave can be scattered on the piezoelectric material layer 31 corresponding to the third auxiliary pseudo-finger 336, 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 third auxiliary pseudo-finger 336, 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.

[0095] For example, along the direction perpendicular to the length of the first busbar 321, the projections of the third auxiliary spur finger 336 and the first spur finger 326 on the first busbar 321 can at least partially overlap; of course, the projections of the third auxiliary spur finger 336 and the first spur finger 326 on the first busbar 321 can also be set at intervals.

[0096] Referring to Figures 10 and 11, in some embodiments, the transducer 32 further includes a fourth auxiliary pseudo-finger 337, which is disposed between the first auxiliary busbar 327 and the first busbar 321, with the fourth auxiliary pseudo-finger 337 spaced apart from both the first auxiliary busbar 327 and the first busbar 321. This arrangement reduces the sound velocity in the piezoelectric material layer 31 corresponding to the fourth auxiliary pseudo-finger 337, allowing sound waves to be scattered on the piezoelectric material layer 31, thus preventing sound 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 337, 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.

[0097] In some implementations, the fourth auxiliary pseudo-finger 337 can be located between the third auxiliary pseudo-finger 336 and the first pseudo-finger 326, and the fourth auxiliary pseudo-finger 337 is spaced apart from both the third auxiliary pseudo-finger 336 and the first pseudo-finger 326. For example, along a direction perpendicular to the length of the first busbar 321, the projections of the fourth auxiliary pseudo-finger 337 and the first pseudo-finger 326 onto the first busbar 321 can at least partially overlap; of course, the projections of the fourth auxiliary pseudo-finger 337 and the first pseudo-finger 326 onto the first busbar 321 can also be spaced apart.

[0098] Referring to Figure 12, in this embodiment, the transducer 32 further includes a fifth auxiliary pseudo-finger 339. The fifth auxiliary pseudo-finger 339 is disposed between the second busbar 322 and the first busbar 321, and the second insertion finger 325 is connected to the second busbar 322 through the fifth auxiliary pseudo-finger 339. This arrangement can reduce the sound velocity of a portion of the piezoelectric material layer 31 corresponding to the fifth auxiliary pseudo-finger 339, 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 339, thus preventing the sound waves from leaking out of the second busbar 322.

[0099] For example, along a direction parallel to the piezoelectric material layer 31 and parallel to the length of the second busbar 322, the width of the fifth auxiliary dummy finger 339 is greater than the width of the second intercalation finger 325. This configuration can further reduce the sound velocity of the portion of the piezoelectric material layer 31 corresponding to the fifth auxiliary dummy finger 339, and further prevent sound waves from leaking out of the second busbar 322.

[0100] It is understandable that the fifth auxiliary pseudofinger 339 can be integrated with the second interdigitated finger 325, meaning that the fifth auxiliary pseudofinger 339 and the second interdigitated finger 325 can be formed simultaneously using the same process. The materials of the fifth auxiliary pseudofinger 339 and the second interdigitated finger 325 can be the same, but their widths are unequal, resulting in a lower sound velocity in the piezoelectric material layer 31 corresponding to the fifth auxiliary pseudofinger 339, thus causing sound waves to be reflected.

[0101] Referring again to Figure 12, in the implementation of transducer 32 including a second auxiliary busbar 329 and a second connecting post 330, transducer 32 further includes a sixth auxiliary pseudo-finger 340. The sixth auxiliary pseudo-finger 340 is disposed between the second auxiliary busbar 329 and the second busbar 322, and the second connecting post 330 is connected to the second busbar 322 through the sixth auxiliary pseudo-finger 340. With this configuration, the sixth auxiliary pseudo-finger 340 can further increase the density of the side of the second busbar 322 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 the noise formed by the 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 340 is located is less than the sound velocity of the piezoelectric material layer 31 on the side of the third pseudo-finger 332 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 340 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.

[0102] For example, along a direction parallel to the piezoelectric material layer 31 and parallel to the length of the second busbar 322, the width of the sixth auxiliary pseudo-finger 340 is greater than the width of the second connecting post 330. This configuration increases the mass of the sixth auxiliary pseudo-finger 340, 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.

[0103] In some embodiments, the transducer 32 further includes a seventh auxiliary pseudo-finger 341, which is disposed between the second auxiliary busbar 329 and the second busbar 322, and is connected to the second auxiliary busbar 329; the seventh auxiliary pseudo-finger 341 is spaced apart from the third pseudo-finger 332. This configuration can reduce the sound velocity of the piezoelectric material layer 31 corresponding to the seventh auxiliary pseudo-finger 341, so that the sound wave can be scattered on the piezoelectric material layer 31 corresponding to the seventh auxiliary pseudo-finger 341, 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 341, 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.

[0104] For example, along the direction perpendicular to the length of the second busbar 322, the projections of the seventh auxiliary spur finger 341 and the third spur finger 332 on the second busbar 322 can at least partially overlap; of course, the projections of the seventh auxiliary spur finger 341 and the third spur finger 332 on the second busbar 322 can also be set at intervals.

[0105] In some embodiments, the transducer 32 further includes an eighth auxiliary pseudo-finger 342, which is disposed between the second auxiliary busbar 329 and the second busbar 322, with the eighth auxiliary pseudo-finger 342 spaced apart from both the second auxiliary busbar 329 and the second busbar 322. This arrangement reduces the sound velocity in the piezoelectric material layer 31 corresponding to the eighth auxiliary pseudo-finger 342, allowing sound waves to be scattered on the piezoelectric material layer 31, 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 342, 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.

[0106] In some implementations, the eighth auxiliary pseudo-finger 342 may be located between the seventh auxiliary pseudo-finger 341 and the third pseudo-finger 332, and the eighth auxiliary pseudo-finger 342 is spaced apart from both the seventh auxiliary pseudo-finger 341 and the third pseudo-finger 332. For example, along a direction perpendicular to the length of the second busbar 322, the projections of the eighth auxiliary pseudo-finger 342 and the third pseudo-finger 332 onto the second busbar 322 may at least partially overlap; of course, the projections of the eighth auxiliary pseudo-finger 342 and the third pseudo-finger 332 onto the second busbar 322 may also be spaced apart.

[0107] 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 surface acoustic wave 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: The first busbar and the second busbar, and the spacing between the first busbar and the second busbar; A first insert and a second insert are disposed at an interval between the first busbar and the second busbar. The first insert is connected to the first busbar, and the second insert is connected to the second busbar. The first dummy finger is disposed on the side of the first busbar opposite to the second busbar, and the first dummy finger is connected to the first busbar.

2. The surface acoustic wave resonator according to claim 1, characterized in that, The transducer further includes a second dummy finger, which is disposed between the first busbar and the second busbar, and is connected to the first busbar.

3. The surface acoustic wave resonator according to claim 1 or 2, characterized in that, The transducer further includes a first auxiliary dummy finger, which is disposed between the first busbar and the second busbar, and the first insertion finger is connected to the first busbar through the first auxiliary dummy finger.

4. The surface acoustic wave resonator according to claim 3, characterized in that, Along the length of the first busbar, the width of the first auxiliary dummy finger is greater than the width of the first insertion finger.

5. The surface acoustic wave resonator according to any one of claims 1-4, characterized in that, The transducer further includes a first auxiliary busbar and a first connecting post. The first auxiliary busbar is disposed on the side of the first busbar away from the second busbar, and the first auxiliary busbar is parallel to and spaced apart from the first busbar. The first connecting post is disposed between the first auxiliary busbar and the first busbar, with one end of the first connecting post connected to the first auxiliary busbar and the other end of the first connecting post connected to the first busbar.

6. The surface acoustic wave resonator according to claim 5, characterized in that, The transducer further includes a second auxiliary pseudofinger, which is disposed between the first auxiliary busbar and the first busbar, and the first connecting post is connected to the first busbar through the second auxiliary pseudofinger.

7. The surface acoustic wave resonator according to claim 6, characterized in that, Along the length of the first busbar, the width of the second auxiliary dummy finger is greater than the width of the first connecting post.

8. The surface acoustic wave resonator according to claim 6 or 7, characterized in that, The transducer also includes a third auxiliary dummy finger, which is disposed between the first auxiliary busbar and the first busbar, and is connected to the first auxiliary busbar; the third auxiliary dummy finger is spaced apart from the first dummy finger.

9. The surface acoustic wave resonator according to any one of claims 5-8, characterized in that, The transducer also includes a fourth auxiliary dummy finger, which is disposed between the first auxiliary busbar and the first busbar, and is spaced apart from both the first auxiliary busbar and the first busbar.

10. The surface acoustic wave resonator according to any one of claims 5-9, characterized in that, The length directions of the first busbar and the second busbar are parallel, and the distance between the first busbar and the first auxiliary busbar is 1.3L1-2.8L1; along a direction parallel to the piezoelectric material layer and perpendicular to the length of the first busbar, the thickness of the first dummy finger is 0.1L1-0.4L1, where L1 is the shortest distance between the center line of the first dummy finger and the center line of the second dummy finger.

11. The surface acoustic wave resonator according to any one of claims 1-10, characterized in that, Along the length of the first busbar, the width of the first dummy finger is greater than or equal to 0.4L1, where L1 is the shortest distance between the center line of the first dummy finger and the center line of the second dummy finger.

12. The surface acoustic wave resonator according to claim 10, characterized in that, Along the length of the first busbar, the width of the first dummy finger is less than or equal to 0.8L1; along the length of the first busbar, the first dummy finger has a first midpoint, the first insert finger has a second midpoint, and the distance between the first midpoint and the second midpoint is 0.5L1-1.5L1.

13. A filter, characterized in that, include: A plurality of surface acoustic wave (SAW) resonators, wherein at least one is a SAW resonator according to any one of claims 1-12, and at least two SAW resonators are connected in series or in parallel among the plurality of SAW resonators.

14. A communication chip, characterized in that, include: The radio frequency front-end circuit and the filter of claim 13, wherein the radio frequency front-end circuit includes a power amplifier and / or a low-noise amplifier, and the radio frequency front-end circuit is coupled to the filter.

15. An electronic device, characterized in that, include: The antenna and the communication chip of claim 14, wherein the communication chip is coupled to the antenna.

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