Surface acoustic wave resonator, filter, communication chip and electronic equipment

Abstract

The invention discloses a surface acoustic wave resonator, a filter, a communication chip and electronic equipment, and aims to solve the problem of poor communication performance. In a transducer of the surface acoustic wave resonator, a first false finger is arranged on one side, deviating from a second bus bar, of a first bus bar, and the first false finger is connected with the first bus bar. The first false finger can increase the density of the side, deviating from the second bus bar, of the first bus bar, so that formation of sound waves of anti-resonance points with the frequency higher than that of the first resonance is prevented, clutters formed by coupling of the sound waves and sound waves corresponding to the second resonance are reduced, and the communication performance is improved. Besides, sound waves of the anti-resonance point with the frequency higher than that of the first resonance and sound waves corresponding to the second resonance can be scattered on the piezoelectric material layer near the first false finger, so that coupling of the sound waves of the anti-resonance point with the frequency higher than that of the first resonance and the sound waves corresponding to the second resonance is prevented, clutters are further reduced, and the communication performance is further improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of communication, and specifically relate to a surface acoustic wave resonator, a filter, a communication chip and an electronic device. BACKGROUND

[0002] Electronic devices (such as mobile phones, tablet computers, smart watches, etc.) are generally provided with filters to filter signals through the filters, thereby improving communication quality. In related technologies, a filter generally includes a surface acoustic wave resonator. The surface acoustic wave resonator can convert an electrical signal into a sound wave when working. The sound wave includes a sound wave corresponding to a first mode and a sound wave corresponding to a second mode. The resonance frequencies of the sound wave corresponding to the first mode and the sound wave corresponding to the second mode are different. However, in related technologies, the sound wave corresponding to the first mode and the sound wave corresponding to the second mode are prone to coupling, thereby forming spurious waves and affecting communication performance. SUMMARY

[0003] Embodiments of the present application provide a surface acoustic wave resonator, a filter, a communication chip and an electronic device to reduce spurious waves and improve communication performance.

[0004] In a first aspect, an embodiment of the present application provides a surface acoustic wave resonator, comprising: a piezoelectric material layer and a transducer; the transducer is arranged on a surface of the piezoelectric material layer, and the transducer is configured to drive the piezoelectric material layer to vibrate to form a sound wave. The transducer includes a first bus bar, a second bus bar, a first interdigital transducer and a second interdigital transducer. The first bus bar and the second bus bar are arranged in a spaced manner. The first interdigital transducer and the second interdigital transducer are arranged in a spaced manner between the first bus bar and the second bus bar. The first interdigital transducer is connected to the first bus bar, and the second interdigital transducer is connected to the second bus bar. The transducer further includes a first dummy finger. The first dummy finger is arranged on a side of the first bus bar away from the second bus bar, and the first dummy finger is connected to the first bus bar.

[0005] Through the above arrangement, the first dummy finger can increase the density of the side of the first bus bar away from the second bus bar, thereby preventing the formation of a sound wave (a Rayleigh transverse mode corresponding sound wave) with a frequency higher than the anti-resonance point of the first resonance, to reduce the spurious waves formed by the coupling between the sound wave and the sound wave corresponding to the second resonance, and to improve the communication performance. In addition, the increase in the density of the side of the first bus bar away from the second bus bar causes the sound speed of the part of the piezoelectric material layer where the first dummy finger is located to be less than the sound speed of the part of the piezoelectric material layer away from the first bus bar on the side of the first dummy finger. Therefore, the sound wave (a Rayleigh transverse mode corresponding sound wave) with a frequency higher than the anti-resonance point of the first resonance and the sound wave (a SH mode corresponding sound wave) corresponding to the second resonance will be scattered (such as reflected and / or refracted) on the piezoelectric material layer near the first dummy finger, to prevent the coupling between 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, and to further reduce the spurious waves and further improve the communication performance.

[0006] In some embodiments that can include the above-mentioned embodiments, the transducer further comprises a first auxiliary bus bar and a first connecting column, the first auxiliary bus bar is arranged on the side of the first bus bar away from the second bus bar, the first auxiliary bus bar is parallel to and spaced apart from the first bus bar; the first connecting column is arranged between the first auxiliary bus bar and the first bus bar, one end of the first connecting column is connected with the first auxiliary bus bar, and the other end of the first connecting column is connected with the first bus bar.

[0007] In this way, the first auxiliary bus bar receives the electrical signal and feeds it into the first bus bar through the first connecting column, thereby causing the piezoelectric material layer near the first finger to vibrate and generate sound waves. The sound speed of the piezoelectric material layer corresponding to the first auxiliary bus bar can be different from the sound speed of the piezoelectric material layer between the first auxiliary bus bar and the first bus bar, and the sound waves can be reflected on the piezoelectric material layer corresponding to the first auxiliary bus bar to further prevent the sound waves from leaking.

[0008] In some embodiments that can include the above-mentioned embodiments, the transducer further comprises a second auxiliary bus bar and a second connecting column, the second auxiliary bus bar is arranged on the surface of the piezoelectric material layer, the second auxiliary bus bar is arranged on the side of the second bus bar away from the first bus bar, the second auxiliary bus bar is spaced apart from the second bus bar; the second connecting column is arranged between the second auxiliary bus bar and the second bus bar, one end of the second connecting column is connected with the second auxiliary bus bar, and the other end of the second connecting column is connected with the second bus bar.

[0009] In this way, the second auxiliary bus bar receives the electrical signal and feeds it into the second bus bar through the second connecting column, thereby causing the piezoelectric material layer near the second finger to vibrate and generate sound waves. The sound speed of the piezoelectric material layer corresponding to the second auxiliary bus bar can be different from the sound speed of the piezoelectric material layer between the second auxiliary bus bar and the second bus bar, and the sound waves can be reflected on the piezoelectric material layer corresponding to the second auxiliary bus bar to further prevent the sound waves from leaking.

[0010] In some embodiments that can include the above-mentioned embodiments, the transducer further comprises a second dummy finger, the second dummy finger is arranged between the first bus bar and the second bus bar, and the second dummy finger is connected with the first bus bar. In this way, the sound speed of the part of the piezoelectric material layer corresponding to the second dummy finger can be reduced, so that the sound waves on the piezoelectric material layer corresponding to the transmission channel are reflected at the position where the second dummy finger is located, thereby preventing the sound waves from leaking out of the first bus bar.

[0011] In some embodiments that can include the above-mentioned embodiments, the transducer further comprises a first auxiliary dummy finger, the first auxiliary dummy finger is arranged between the first bus bar and the second bus bar, and the first connecting finger is connected to the first bus bar through the first auxiliary dummy finger. In this way, the sound speed of the part of the piezoelectric material layer corresponding to the first auxiliary dummy finger can be reduced, and the sound wave on the part of the piezoelectric material layer corresponding to the transmission channel can be reflected at the position where the first auxiliary dummy finger is located, so as to prevent the sound wave from leaking out of the first bus bar.

[0012] In some embodiments that can include the above-mentioned embodiments, the width of the first auxiliary dummy finger is greater than the width of the first connecting finger in the direction along the length of the first bus bar. In this way, the sound speed of the part of the piezoelectric material layer corresponding to the first auxiliary dummy finger can be further reduced, and the sound wave can be further prevented from leaking out of the first bus bar.

[0013] In some embodiments that can include the above-mentioned embodiments, the transducer further comprises a second auxiliary dummy finger, the second auxiliary dummy finger is arranged between the first auxiliary bus bar and the first bus bar, and the first connecting column is connected to the first bus bar through the second auxiliary dummy finger. In this way, the second auxiliary dummy finger can further increase the density of the side of the first bus bar away from the second bus bar, and further prevent the formation of the sound wave (the sound wave corresponding to the Rayleigh transverse mode) with a frequency higher than the anti-resonance point of the first resonance, so as to reduce the spurious wave formed by the coupling between the sound wave and the sound wave corresponding to the second resonance, and improve the communication performance. In addition, the sound speed of the part of the piezoelectric material layer where the second auxiliary dummy finger is located is less than the sound speed of the part of the piezoelectric material layer on the side of the first dummy finger away from the first bus bar. Therefore, the sound wave (the sound wave corresponding to the Rayleigh transverse mode) with a frequency higher than the anti-resonance point of the first resonance and the sound wave (the sound wave corresponding to the SH mode) corresponding to the second resonance will be scattered (such as reflected and / or refracted) on the piezoelectric material layer near the second auxiliary dummy finger, so as to prevent the coupling between 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, further reduce the spurious wave, and further improve the communication performance.

[0014] In some embodiments that can include the above-mentioned embodiments, the width of the second auxiliary dummy finger is greater than the width of the first connecting column in the direction parallel to the piezoelectric material layer and parallel to the length of the first bus bar. In this way, the mass of the second auxiliary dummy finger can be increased, the formation of the sound wave (the sound wave corresponding to the Rayleigh transverse mode) with a frequency higher than the anti-resonance point of the first resonance can be further prevented, and the reflection effect on the sound wave (the sound wave corresponding to the Rayleigh transverse mode) with a frequency higher than the anti-resonance point of the first resonance and the sound wave (the sound wave corresponding to the SH mode) corresponding to the second resonance can be improved, so as to further prevent the coupling between 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.

[0015] In some embodiments that can include the above-mentioned embodiments, the transducer further comprises a third auxiliary dummy finger, the third auxiliary dummy finger is disposed between the first auxiliary bus bar and the first bus bar, and the third auxiliary dummy finger is connected with the first auxiliary bus bar; the third auxiliary dummy finger is spaced apart from the first dummy finger. In this way, the acoustic velocity of the piezoelectric material layer corresponding to the third auxiliary dummy finger can be reduced, so that the sound wave can be scattered on the piezoelectric material layer corresponding to the third auxiliary dummy finger to prevent the sound wave from leaking; 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 corresponding to the third auxiliary dummy finger, 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 from being coupled.

[0016] In some embodiments that can include the above-mentioned embodiments, the transducer further comprises a fourth auxiliary dummy finger, the fourth auxiliary dummy finger is disposed between the first auxiliary bus bar and the first bus bar, and the fourth auxiliary dummy finger is spaced apart from both the first auxiliary bus bar and the first bus bar. In this way, the acoustic velocity of the piezoelectric material layer corresponding to the fourth auxiliary dummy finger can be reduced, so that the sound wave can be scattered on the piezoelectric material layer corresponding to the fourth auxiliary dummy finger to prevent the sound wave from leaking; 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 corresponding to the fourth auxiliary dummy finger, 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 from being coupled.

[0017] In some embodiments that can include the above-mentioned embodiments, the length direction of the first bus bar and the second bus bar are parallel, the distance between the first bus bar and the first auxiliary bus bar is 1.3L1-2.8L1; the thickness of the first dummy finger in the direction parallel to the piezoelectric material layer and perpendicular to the length of the first bus bar is 0.1L1-0.4L1, wherein L1 is the shortest distance between the center line of the first finger and the center line of the second finger.

[0018] Through the above-mentioned arrangement, the thickness of the first dummy finger is moderate, which can ensure that the first dummy finger has sufficient thickness in the direction perpendicular to the length of the first bus bar, so that the first dummy finger can suppress the formation of 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 make 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) scattered on the piezoelectric material layer near the first dummy finger. At the same time, it can also avoid that the thickness of the first dummy finger is too large.

[0019] In some embodiments which can comprise the above-mentioned embodiments, the width of the first dummy finger in the direction along the length of the first bus bar is greater than or equal to 0.4L1, where L1 is the shortest distance between the center line of the first finger and the center line of the second finger. In this way, the first dummy finger can be ensured to have a sufficient width in the direction parallel to the length of the first bus bar, so that the first dummy finger can suppress the formation of sound waves (Rayleigh transverse mode corresponding sound waves) with a frequency higher than the anti-resonance point of the first resonance, while also avoiding the width of the first dummy finger being too large.

[0020] In some embodiments which can comprise the above-mentioned embodiments, the width of the first dummy finger in the direction along the length of the first bus bar is less than or equal to 0.8L1; the first dummy finger has a first midpoint and the first finger has a second midpoint, and the distance between the first midpoint and the second midpoint is 0.5L1-1.5L1. In this way, the width of the first dummy finger can be avoided from being too large, and in turn, the sound waves can be prevented from propagating outward through the first dummy finger, i.e., the sound waves can be prevented from leaking outward through the first dummy finger.

[0021] In some embodiments which can comprise the above-mentioned embodiments, the transducer further comprises a third dummy finger, the third dummy finger being arranged on the side of the second bus bar away from the transmission channel. The third dummy finger is connected to the second bus bar. Through the above arrangement, the third dummy finger can increase the density of the side of the second bus bar away from the transmission channel, and in turn, prevent the formation of sound waves (Rayleigh transverse mode corresponding sound waves) with a frequency higher than the anti-resonance point of the first resonance, so as to reduce the spurious waves formed by the coupling between the sound waves with a frequency higher than the anti-resonance point of the first resonance and the sound waves corresponding to the second resonance, and improve the communication performance. In addition, the sound speed of the part of the piezoelectric material layer where the third dummy finger is located is less than the sound speed of the part of the piezoelectric material layer on the side of the third dummy finger away from the transmission channel. Therefore, the sound waves (Rayleigh transverse mode corresponding sound waves) with a frequency higher than the anti-resonance point of the first resonance and the sound waves (SH mode corresponding sound waves) corresponding to the second resonance will be scattered (such as reflected and / or refracted) on the piezoelectric material layer near the third dummy finger, so as to prevent the coupling between the sound waves with a frequency higher than the anti-resonance point of the first resonance and the sound waves corresponding to the second resonance, further reduce the spurious waves, and further improve the communication performance.

[0022] In some embodiments which can comprise the above-mentioned embodiments, the transducer further comprises a fourth dummy finger, the fourth dummy finger being arranged between the first bus bar and the second bus bar, and the fourth dummy finger being connected to the second bus bar; that is, the fourth dummy finger is arranged on the piezoelectric material layer, and the fourth dummy finger is connected to the second bus bar. In this way, the sound speed of the part of the piezoelectric material layer corresponding to the fourth dummy finger can be reduced, so that the sound waves on the piezoelectric material layer corresponding to the transmission channel are reflected at the position where the fourth dummy finger is located, and the sound waves are prevented from leaking outward to the second bus bar.

[0023] In some embodiments that can include the above-mentioned embodiments, the transducer further comprises a fifth auxiliary dummy finger, the fifth auxiliary dummy finger is arranged between the first bus bar and the second bus bar, and the second connecting column is connected to the second bus bar through the fifth auxiliary dummy finger. In this way, the sound velocity of the part of the piezoelectric material layer corresponding to the fifth auxiliary dummy finger can be reduced, so that the sound wave on the piezoelectric material layer corresponding to the transmission channel is reflected at the position where the fifth auxiliary dummy finger is located, and the leakage of the sound wave to the outside of the second bus bar is prevented.

[0024] In some embodiments that can include the above-mentioned embodiments, the transducer further comprises a sixth auxiliary dummy finger, the sixth auxiliary dummy finger is arranged between the second auxiliary bus bar and the second bus bar, and the second connecting column is connected to the second bus bar through the sixth auxiliary dummy finger. In this way, the sixth auxiliary dummy finger can further increase the density of the side of the second bus bar away from the transmission channel, further prevent the formation of sound waves (Rayleigh transverse mode corresponding sound waves) with a frequency higher than the anti-resonance point of the first resonance, and reduce the spurious waves formed by the coupling between the sound waves corresponding to the second resonance, so as to improve the communication performance. In addition, the sound velocity of the part of the piezoelectric material layer where the sixth auxiliary dummy finger is located is less than the sound velocity of the part of the piezoelectric material layer on the side of the third dummy finger away from the transmission channel. Therefore, the sound waves (Rayleigh transverse mode corresponding sound waves) with a frequency higher than the anti-resonance point of the first resonance and the sound waves (SH mode corresponding sound waves) corresponding to the second resonance will be scattered (such as reflected and / or refracted) on the piezoelectric material layer near the sixth auxiliary dummy finger, so as to prevent the coupling between the sound waves with a frequency higher than the anti-resonance point of the first resonance and the sound waves corresponding to the second resonance, further reduce the spurious waves, and further improve the communication performance.

[0025] In some embodiments that can include the above-mentioned embodiments, the transducer further comprises a seventh auxiliary dummy finger, the seventh auxiliary dummy finger is arranged between the second auxiliary bus bar and the second bus bar, and the seventh auxiliary dummy finger is connected to the second auxiliary bus bar; the seventh auxiliary dummy finger is arranged at intervals with the third dummy finger. In this way, the sound velocity of the piezoelectric material layer corresponding to the seventh auxiliary dummy finger can be reduced, so that the sound wave can be scattered on the piezoelectric material layer corresponding to the seventh auxiliary dummy finger, so as to prevent the leakage of the sound wave; in addition, since the sound waves (Rayleigh transverse mode corresponding sound waves) with a frequency higher than the anti-resonance point of the first resonance and the sound waves (SH mode corresponding sound waves) corresponding to the second resonance are scattered on the piezoelectric material layer corresponding to the seventh auxiliary dummy finger, the coupling between the sound waves with a frequency higher than the anti-resonance point of the first resonance and the sound waves corresponding to the second resonance can be further prevented.

[0026] In some embodiments which can include the above-mentioned embodiments, the transducer further comprises an eighth auxiliary dummy finger, the eighth auxiliary dummy finger is arranged between the second auxiliary bus bar and the second bus bar, and the eighth auxiliary dummy finger is arranged in a manner spaced apart from both the second auxiliary bus bar and the second bus bar. In this way, the acoustic velocity of the piezoelectric material layer corresponding to the eighth auxiliary dummy finger can be reduced, so that the acoustic wave can be scattered on the piezoelectric material layer corresponding to the eighth auxiliary dummy finger to prevent acoustic wave leakage; in addition, since the acoustic wave (Rayleigh transverse mode corresponding acoustic wave) with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave (SH mode corresponding acoustic wave) corresponding to the second resonance are both scattered on the piezoelectric material layer corresponding to the eighth auxiliary dummy finger, the acoustic wave with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave corresponding to the second resonance can be further prevented from being coupled.

[0027] In a second aspect, the embodiments of the present application further provide a filter, comprising a plurality of surface acoustic wave resonators, at least one of which is the 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.

[0028] The filter in the embodiments of the present application comprises the surface acoustic wave resonator in any of the above-mentioned embodiments, and thus both can solve the same technical problem and achieve the same technical effect.

[0029] In a third aspect, the embodiments of the present application further provide a communication chip, comprising: a radio frequency front-end circuit and a filter as described above, the radio frequency front-end circuit comprises a power amplifier and / or a low noise amplifier, and the radio frequency front-end circuit is coupled with the filter.

[0030] The communication chip in the embodiments of the present application comprises the filter in any of the above-mentioned embodiments, and thus both can solve the same technical problem and achieve the same technical effect.

[0031] In a fourth aspect, the embodiments of the present application further provide an electronic device, comprising: an antenna and a communication chip as described above, the communication chip is coupled with the antenna.

[0032] The electronic device in the embodiments of the present application comprises the communication chip in any of the above-mentioned embodiments, and thus both can solve the same technical problem and achieve the same technical effect. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A structural schematic diagram of an electronic device provided by the embodiments of the present application is shown in FIG. 1;

[0034] Figure 2 A structural schematic diagram of a communication chip provided by the embodiments of the present application is shown in FIG. 2;

[0035] Figure 3 A top view of a surface acoustic wave resonator provided by the embodiments of the present application is shown in FIG. 3;Figure 1 ;

[0036] Figure 4 is Figure 3 a sectional view along A-A direction in the middle;

[0037] Figure 5 is a plot of admittance versus frequency for a transducer without a first dummy finger;

[0038] Figure 6 is a plot of admittance versus frequency for a transducer with a first dummy finger;

[0039] Figure 7 is a top view of a surface acoustic wave resonator provided by an embodiment of the present application Figure 2 ;

[0040] Figure 8 is a top view of a surface acoustic wave resonator provided by an embodiment of the present application Figure 3 ;

[0041] Figure 9 is a top view of a surface acoustic wave resonator provided by an embodiment of the present application Figure 4 ;

[0042] Figure 10 is a top view of a surface acoustic wave resonator provided by an embodiment of the present application Figure 5 ;

[0043] Figure 11 is a top view of a surface acoustic wave resonator provided by an embodiment of the present application Figure 6 ;

[0044] Figure 12 is a top view of a surface acoustic wave resonator provided by an embodiment of the present application Figure 7 .

[0045] BRIEF DESCRIPTION OF REFERENCE NUMERALS: 11: frame; 12: display panel; 13: back cover; 14: mainboard; 15: antenna; 20: communication chip; 21: radio frequency 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 bus bar; 322: second bus bar; 323: transmission channel; 324: first interdigital transducer; 325: second interdigital transducer; 326: first dummy finger; 327: first auxiliary bus bar; 328: first connecting column; 329: second auxiliary bus bar; 330: second connecting column; 331: second dummy finger; 332: third dummy finger; 333: expansion part; 334: first auxiliary dummy finger; 335: second auxiliary dummy finger; 336: third auxiliary dummy finger; 337: fourth auxiliary dummy finger; 338: fourth dummy finger; 339: fifth auxiliary dummy finger; 340: sixth auxiliary dummy finger; 341: seventh auxiliary dummy finger; 342: eighth auxiliary dummy finger. Detailed Implementation

[0046] 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.

[0047] 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.

[0048] 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.

[0049] This application provides an electronic device, which may include devices such as mobile phones, tablets, laptops, smart bracelets, and smartwatches. Figure 1 As shown, 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 surrounds a mounting cavity, the motherboard 14 is disposed in 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.

[0050] 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.

[0051] It can be understood that the coupling in the embodiments of the present application can be understood as direct coupling and / or indirect coupling. The direct coupling can also be referred to as "electrical connection", which means that the components are in physical contact and electrically conductive. It can also be understood as a form of connection between different components in the circuit structure through the entity circuit such as copper foil or wire of the printed circuit board (PCB) that can transmit electrical signals. The "indirect coupling" can be understood as electrical conduction through space / non-contact. In an embodiment, the indirect coupling can also be referred to as capacitive coupling, for example, the coupling between the gap between the two conductive parts forms an equivalent capacitor to realize signal transmission.

[0052] Please refer to Figure 2 In some embodiments, the communication chip 20 can include a radio frequency front-end circuit 21 and a filter 22, the radio frequency front-end circuit 21 is coupled with the filter 22, and the filter 22 is coupled with the antenna 15 shown. The coupling between the radio frequency front-end circuit 21 and the antenna 15 can be realized through the filter 22, and at the same time, the filter 22 can remove the signals that are not required for communication, thereby avoiding interference and improving communication quality. Figure 1

[0053] In some implementations, the radio frequency front-end circuit 21 can include a power amplifier 23. The signal from the signal source enters the filter 22 after passing through the power amplifier 23, and then the filter 22 feeds the signal into the antenna 15 to emit the signal outward through the antenna 15. The signal source can include a modulator and other devices capable of outputting radio frequency signals; the power amplifier 23 is used to increase the power of the signal 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.

[0054] In some implementations, the radio frequency front-end circuit 21 can include a low-noise amplifier 24. After the antenna 15 receives the electromagnetic signal in space to form an electrical signal, the signal enters the low-noise amplifier 24 after passing through the filter 22. The signal output by the low-noise amplifier 24 can be transmitted to a demodulator to realize 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 improve the accuracy of the received signal.

[0055] In other implementations, the radio frequency front-end circuit 21 can include a power amplifier 23 and a low-noise amplifier 24. At this time, the radio frequency front-end circuit 21 can be used for signal transmission and reception, thereby improving the communication performance of the electronic device.

[0056] In the above implementations, the radio frequency front-end circuit 21 and the filter 22 can be packaged on the same packaging substrate, thereby improving the compactness of the communication chip 20, and also facilitating the manufacturing and installation of the communication chip 20.​

[0057] In this embodiment, filter 22 includes a plurality of surface acoustic wave (SAW) resonators, at least two of which are connected in series or in parallel. Please refer to... Figure 3 and Figure 4 At least one surface acoustic wave resonator 30 includes a substrate 35, a piezoelectric material layer 31 disposed on the substrate 35, and a transducer 32, wherein the piezoelectric material layer 31 is plate-shaped, and the transducer 32 is disposed on the surface of the piezoelectric material layer 31 with a larger area. Figure 4 On the upper surface (shown in the orientation); when the transducer 32 receives an electrical signal, it drives the surface of the piezoelectric material layer 31 to vibrate, generating sound waves (surface acoustic waves). 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 satisfy a specific resonant frequency can be effectively received; sound waves at 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, ceramic, etc., and this embodiment does not limit the material of the substrate 35.

[0058] 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.

[0059] Continue to refer to Figure 3 and Figure 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 the extension direction (length direction) of the first busbar 321 and the second busbar 322 is... Figure 3The first bus bar 321 and the second bus bar 322 are arranged in parallel along the width direction of the first bus bar 321 and the second bus bar 322, which is a direction parallel to the piezoelectric material layer 31 and perpendicular to the extension direction of the first bus bar 321 and the second bus bar 322. Figure 3 The transmission channel 323 is formed between the first bus bar 321 and the second bus bar 322, and the sound wave can be transmitted near the surface of the piezoelectric material layer 31 corresponding to the transmission channel 323. It can be understood that the transmission channel 323 can be the area between the vertically coinciding parts of the first bus bar 321 and the second bus bar 322 in the orientation shown in FIG. 3. Figure 3 The first bus bar 321 and the second bus bar 322 are arranged in parallel along the width direction of the first bus bar 321 and the second bus bar 322, which is a direction parallel to the piezoelectric material layer 31 and perpendicular to the extension direction of the first bus bar 321 and the second bus bar 322.

[0060] The transducer 32 further comprises a first finger 324 and a second finger 325, which are arranged on the surface of the piezoelectric material layer 31 and located in the transmission channel 323, that is, between the first bus bar 321 and the second bus bar 322. The first finger 324 and the second finger 325 extend on the piezoelectric material layer 31, and the extension direction (length direction) of the first finger 324 and the second finger 325 is parallel, and the first finger 324 and the second finger 325 are arranged in parallel along the width direction of the first finger 324 and the second finger 325, which is a direction perpendicular to the extension direction of the first finger 324 and the second finger 325. The extension direction of the first finger 324 can be perpendicular to the extension direction of the first bus bar 321, or the extension direction of the first finger 324 and the extension direction of the first bus bar 321 have other angles, and the end of the first finger 324 close to the first bus bar 321 is connected to the first bus bar 321, and the end of the first finger 324 close to the second bus bar 322 is arranged away from the second bus bar 322. Similarly, the extension direction of the second finger 325 can be perpendicular to the extension direction of the second bus bar 322, or the extension direction of the second finger 325 and the extension direction of the second bus bar 322 have other angles, and the end of the second finger 325 close to the second bus bar 322 is connected to the second bus bar 322, and the end of the second finger 325 close to the first bus bar 321 is arranged away from the first bus bar 321. The first bus bar 321 and the second bus bar 322 are used to receive radio frequency signals, the first bus bar 321 feeds the signals into the first finger 324, and the second bus bar 322 feeds the signals into the second finger 325, so that the piezoelectric material layer 31 near the first finger 324 and the second finger 325 vibrates, thereby forming a sound wave.

[0061] In some implementations, the first and second plurality of pins 324 and 325 are alternately arranged along the extension direction of the first bus bar 321, that is, one second pin 325 is arranged between two adjacent first pins 324, and one first pin 324 is arranged between two adjacent second pins 325. In this way, the first bus bar 321 can simultaneously feed power to each first pin 324, and the second bus bar 322 can simultaneously feed power to each second pin 325, and the piezoelectric material layer 31 near each first and second pin 324 and 325 can vibrate to form a sound wave, thereby improving the power of the surface acoustic wave resonator 30.

[0062] In some implementations, the first pin 324 and the first bus bar 321 can be an integral structure, and the first pin 324 and the first bus bar 321 can be formed by evaporation, electroplating, or the like. For example, in the evaporation process, a metal layer can be formed on the piezoelectric material layer 31 by evaporation, and then part of the metal can be removed by etching to form the first pin 324 and the first bus bar 321. Similarly, the second bus bar 322 and the second pin 325 can also be an integral structure, and the manufacturing method of the second bus bar 322 and the second pin 325 can be similar to that of the first pin 324 and the first bus bar 321, which will not be described here.

[0063] In some implementations, the first pin 324, the first bus bar 321, the second pin 325, and the second bus bar 322 can be simultaneously formed by the same manufacturing method to reduce the manufacturing difficulty of the surface acoustic wave resonator 30, and on the other hand, to improve the manufacturing efficiency of the surface acoustic wave resonator 30.

[0064] In some embodiments, the first pin 324 can include a plurality of metal layers arranged on the piezoelectric material layer 31, that is, the plurality of metal layers are stacked on the piezoelectric material layer 31 to form the first pin 324. For example, the material of the metal layer can 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. The materials of adjacent metal layers can be different. Since the densities of different metals are different, the overall density of the first pin 324 can be adjusted by reasonably selecting the materials of the metal layers. Similarly, the structure and material of the second pin 325 can be similar to those of the first pin 324, which will not be described here.

[0065] In some examples, the first interdigital transducer 324 and the second interdigital transducer 325 each include at least two metal layers, and a material of one of the metal layers can be aluminum, and a material of one of the metal layers can include one of platinum, molybdenum, and tungsten, so as to ensure that the first interdigital transducer 324 and the second interdigital transducer 325 have a relatively large density. It can be understood that the surface acoustic wave resonator 30 satisfies f = v / (2λ), where f is a resonance frequency of the surface acoustic wave resonator 30 to generate a surface acoustic wave, v is a propagation speed (acoustic speed) of the surface acoustic wave near a surface of the piezoelectric material layer 31, and λ is a wavelength of the surface acoustic wave; when the resonance frequency is constant, reducing the acoustic speed can reduce the wavelength of the surface acoustic wave. In the transducer 32, a shortest distance L1 between a center line (such as a dashed line in Figure 3 ) of the first interdigital transducer 324 and a center line (such as a dashed line in Figure 3 ) of the second interdigital transducer 325 is equal to twice the length of the wavelength; in addition, increasing the density of the first interdigital transducer 324 and the second interdigital transducer 325 can reduce the acoustic speed of the surface of the piezoelectric material layer 31. Therefore, by increasing the density of the first interdigital transducer 324 and the second interdigital transducer 325, the wavelength of the surface acoustic wave can be reduced, and the distance between the first interdigital transducer 324 and the second interdigital transducer 325 can be reduced, so that the volume of the transducer 32 and the surface acoustic wave resonator 30 can be reduced, and miniaturization can be facilitated. For example, the density of the first interdigital transducer 324 and the second interdigital transducer 325 can be greater than or equal to 8900 Kg / m 3 .

[0066] With reference still to Figure 3 , in the embodiment, when the surface acoustic wave resonator 30 is working, the transducer 32 generates a surface acoustic wave, and the surface acoustic wave can generate a first resonance (Rayleigh mode) and a second resonance (Shear Horizontal, SH mode) as shown in Figure 5 . Figure 5 In the embodiment, a solid line in represents an absolute value of an admittance, and a dashed line represents a real part of the admittance, a resonance frequency of the first resonance is different from a resonance frequency of the second resonance, and the surface acoustic waves corresponding to the first resonance and the second resonance propagate in a direction substantially parallel to a length of the first bus bar 321 near the surface of the piezoelectric material layer 31 corresponding to the transmission channel 323.

[0067] In some examples, the resonance frequency of the first resonance is less than the resonance frequency of the second resonance, the first resonance includes a resonance point and an anti-resonance point, and when the transducer 32 forms the surface acoustic wave corresponding to the first resonance, the transducer 32 can form a surface acoustic wave (such as a surface acoustic wave corresponding to a Rayleigh transverse mode, as shown by an M area in Figure 5 ) with a frequency higher than the anti-resonance point on a side of the first bus bar 321 away from the transmission channel 323, and the surface acoustic wave can be coupled (acoustic wave interference) with a surface acoustic wave (a surface acoustic wave corresponding to the SH mode) corresponding to the second resonance that leaks to the side of the first bus bar 321 away from the transmission channel 323, and thus a clutter wave (such as a clutter wave corresponding to the Rayleigh transverse mode, as shown by an N area in Figure 5The spurious wave will form an interference signal and affect the communication performance.

[0068] With reference to the foregoing Figure 3 In the embodiment, the transducer 32 further comprises a first dummy finger 326. The first dummy finger 326 is arranged on the side of the first bus bar 321 away from the second bus bar 322, that is, the first dummy finger 326 is arranged on the piezoelectric material layer 31 and located outside the transmission channel 323. The first dummy finger 326 is connected with the first bus bar 321, which can be understood as that the first dummy finger 326 is in contact with the first bus bar 321. For example, the first dummy finger 326 and the first bus bar 321 can be an integral structure, or the first dummy finger 326 and the first bus bar 321 are connected by welding or other methods.

[0069] Through the above arrangement, the first dummy finger 326 can increase the density of the side of the first bus bar 321 away from the second bus bar 322, thereby preventing the formation of sound waves with a frequency higher than the anti-resonance point of the first resonance (Rayleigh transverse mode corresponding sound waves), and reducing the spurious wave formed by the coupling between the sound waves corresponding to the second resonance and the sound waves, and improving the communication performance. In addition, the increase in the density of the side of the first bus bar 321 away from the second bus bar 322 makes the sound speed of the part of the piezoelectric material layer 31 where the first dummy finger 326 is located smaller than the sound speed of the part of the piezoelectric material layer 31 on the side of the first dummy finger 326 away from the transmission channel 323. Therefore, the sound waves with a frequency higher than the anti-resonance point of the first resonance (Rayleigh transverse mode corresponding sound waves) and the sound waves corresponding to the second resonance (SH mode corresponding sound waves) will be scattered (such as reflected and / or refracted) on the piezoelectric material layer 31 near the first dummy finger 326, so as to prevent the coupling between the sound waves with a frequency higher than the anti-resonance point of the first resonance and the sound waves corresponding to the second resonance, further reduce the spurious wave, and further improve the communication performance.

[0070] Figure 3 In the figure, the closer the line segment is to the transducer 32, the lower the sound speed of the piezoelectric material layer 31 at the position corresponding to the transducer 32. It can be seen from the figure that the sound speed of the piezoelectric material layer 31 at the position corresponding to the transducer 32 is not equal to the sound speed of the piezoelectric material layer 31 at the position corresponding to the transducer 32. Figure 3 It can be seen that the sound speed of the piezoelectric material layer 31 in the region where the first dummy finger 326 is located is not equal to the sound speed of the piezoelectric material layer 31 in the adjacent region, and the sound waves with a frequency 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 dummy finger 326 to reduce the coupling.

[0071] Please refer to Figure 5 and Figure 6 , Figure 5 is a graph of the admittance-frequency relationship of a transducer without a first dummy finger, Figure 6This is a graph showing the admittance versus frequency of a transducer with a first pseudo-finger. The solid line represents the absolute value of the admittance, and the dashed line represents the real part of the admittance. (Compare...) Figure 5 and Figure 6 It can be seen that setting the first pseudo-finger 326 reduces the frequency of sound waves at the anti-resonance point higher than the first resonance (such as...). Figure 5 and Figure 6 (as shown in region M) and the clutter formed by the acoustic wave coupling corresponding to the second resonance (such as...) Figure 5 and Figure 6 (As shown in region N). Furthermore, since the first pseudo-finger 326 can reflect the acoustic wave corresponding to the second resonance to the piezoelectric material layer 31 corresponding to the transmission channel 323, the first pseudo-finger 326 is configured to make the imaginary admittance curve between the resonant point and the anti-resonant point of the second resonance smoother (e.g., ...). Figure 3 and Figure 3 (As shown in the P region), this reduces the acoustic waves corresponding to the transverse mode of SH.

[0072] Continue to refer to Figure 7 Each of the first insert finger 324 has an expansion portion 333 at one end near the first busbar 321 and at one end near the second busbar 322. Along the width direction perpendicular to the length of the first busbar 321, the size of the expansion portion 333 is larger than the size of other locations on the first insert finger 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 layer 31 corresponding to the first insert 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 (the side away from the transmission channel 323). Similarly, each of the second insert finger 325 has an expansion portion 333 at one end near the first busbar 321 and the other end 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.

[0073] Continue to refer to Figure 7In some embodiments, the transducer 32 further comprises a first auxiliary bus bar 327 and a first connecting post 328. The first auxiliary bus bar 327 is located on the surface of the piezoelectric material layer 31, and is disposed on the side of the first bus bar 321 away from the second bus bar 322. The first auxiliary bus bar 327 is spaced apart from the first bus bar 321. The first connecting post 328 is disposed between the first auxiliary bus bar 327 and the first bus bar 321. One end of the first connecting post 328 is connected to the first auxiliary bus bar 327, and the other end of the first connecting post 328 is connected to the first bus bar 321. The first auxiliary bus bar 327 receives an electrical signal and feeds the first bus bar 321 through the first connecting post 328, so that the piezoelectric material layer 31 near the first interdigital transducer 324 vibrates to generate a sound wave. The sound speed of the piezoelectric material layer 31 corresponding to the first auxiliary bus bar 327 can be different from the sound speed of the piezoelectric material layer 31 between the first auxiliary bus bar 327 and the first bus bar 321. The sound wave can be reflected on the piezoelectric material layer 31 corresponding to the first auxiliary bus bar 327 to further prevent the sound wave from leaking.

[0074] In some embodiments, the transducer 32 further comprises a second auxiliary bus bar 329 and a second connecting post 330. The second auxiliary bus bar 329 is located on the surface of the piezoelectric material layer 31, and is disposed on the side of the second bus bar 322 away from the first bus bar 321. The second auxiliary bus bar 329 is spaced apart from the second bus bar 322. The second connecting post 330 is disposed between the second auxiliary bus bar 329 and the second bus bar 322. One end of the second connecting post 330 is connected to the second auxiliary bus bar 329, and the other end of the second connecting post 330 is connected to the second bus bar 322. The second auxiliary bus bar 329 receives an electrical signal and feeds the second bus bar 322 through the second connecting post 330, so that the piezoelectric material layer 31 near the second interdigital transducer 325 vibrates to generate a sound wave. The sound speed of the piezoelectric material layer 31 corresponding to the second auxiliary bus bar 329 can be different from the sound speed of the piezoelectric material layer 31 between the second auxiliary bus bar 329 and the second bus bar 322. The sound wave can be reflected on the piezoelectric material layer 31 corresponding to the second auxiliary bus bar 329 to further prevent the sound wave from leaking.

[0075] Please refer to Figure 3In 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.

[0076] 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.

[0077] 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.

[0078] Continue to refer to Figure 3 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 (e.g., ...). Figure 3 In the 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 pseudo-fingers 326 is λ, and the distance between the second midpoint b of two adjacent second pseudo-fingers 331 is λ. Along the 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 (such as 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 (such as 0.65λ-1.4λ). Figure 3In the middle 1.3L1-2.8L1, for example, the distance can be 0.65λ, λ, 1.4λ, etc., and the thickness L4 of the first dummy finger 326 in the direction parallel to the piezoelectric material layer 31 and perpendicular to the length of the first bus bar 321 is 0.05λ-0.2λ (e.g., 0.05λ, 0.1λ, 0.2λ, etc.). Figure 3 In the middle 0.1L1-0.4L1, for example, L4 can be 0.05λ, 0.1λ, 0.2λ, etc., and correspondingly, the distance L5 between the first dummy finger 326 and the first auxiliary bus bar 327 is 0.6λ-1.2λ (e.g., 0.6λ, 0.9λ, 1.2λ, etc.).

[0079] Through the above arrangement, the thickness of the first dummy finger 326 is moderate, which can ensure that the first dummy finger 326 has sufficient thickness in the direction perpendicular to the length of the first bus bar 321, so that the first dummy finger 326 can suppress the formation of acoustic waves (Rayleigh transverse mode corresponding acoustic waves) with frequencies higher than the anti-resonance point of the first resonance, and make the acoustic waves (Rayleigh transverse mode corresponding acoustic waves) with frequencies higher than the anti-resonance point of the first resonance and the acoustic waves (SH mode corresponding acoustic waves) corresponding to the second resonance scattered on the piezoelectric material layer 31 near the first dummy finger 326. At the same time, it can also avoid that the thickness of the first dummy finger 326 is too large.

[0080] In the above implementation, the thickness L6 of the second dummy finger 331 in the direction parallel to the piezoelectric material layer 31 and perpendicular to the length of the first bus bar 321 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 insertion finger 325 is 0.05λ-0.2λ (e.g., 0.05λ, 0.1λ, 0.2λ, etc.). In this way, the thickness of the second dummy finger 331 is moderate, which can ensure that the second dummy finger 331 has sufficient thickness in the direction perpendicular to the length of the first bus bar 321, so that the acoustic waves are scattered on the piezoelectric material layer 31 near the second dummy finger 331, and at the same time, it can also avoid that the thickness of the second dummy finger 331 is too large. The length L8 of the expansion part 333 in the direction perpendicular to the length of the first bus bar 321 can be 0.6λ-1.2λ (e.g., 0.6λ, 0.9λ, 1.2λ, etc.), so that the expansion part 333 has sufficient length, thereby preventing leakage from the area where the first bus bar 321 is located.

[0081] 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 dummy finger 326 in the direction parallel to the piezoelectric material layer 31 and parallel to the length of the first bus bar 321 is greater than or equal to 0.2λ (e.g., 0.2λ, 0.3λ, 0.4λ, 0.5λ, 0.6λ, 0.7λ, 0.8λ, 0.9λ, 1.0λ, 1.1λ, 1.2λ, etc.). Figure 3L9 can be 0.2λ, 0.325λ, etc. In this way, the first dummy finger 326 can have a sufficient width along the direction parallel to the length of the first bus bar 321, so that the first dummy finger 326 can suppress the formation of the acoustic wave (Rayleigh transverse mode corresponding acoustic wave) with a frequency higher than the anti-resonance point of the first resonance, while avoiding the first dummy finger 326 being too wide.

[0082] In the above implementation, the width L9 of the first dummy finger 326 along the direction parallel to the piezoelectric material layer 31 and parallel to the length of the first bus bar 321 is less than or equal to 0.4λ (e.g. Figure 7 L9 can be 0.4λ, 0.325λ, etc. In this way, the width of the first dummy finger 326 can be avoided being too large, and the acoustic wave can be avoided being transmitted outward through the first dummy finger 326, i.e., the acoustic wave can be avoided being leaked outward by the first dummy finger 326.

[0083] Continuing to refer to Figure 7 and Figure 8 In some embodiments, the transducer 32 further includes a third dummy finger 332, which is disposed on the side of the second bus bar 322 away from the first bus bar 321, i.e., the third dummy finger 332 is disposed on the piezoelectric material layer 31 and located outside the transmission channel 323. The third dummy finger 332 is connected to the second bus bar 322, which can be understood as the third dummy finger 332 being in contact with the second bus bar 322. For example, the third dummy finger 332 and the second bus bar 322 can be in an integrated structure, or the third dummy finger 332 and the second bus bar 322 can be connected by welding or the like.

[0084] Through the above arrangement, the third dummy finger 332 can increase the density of the side of the second bus bar 322 away from the transmission channel 323, thereby preventing the formation of the acoustic wave (Rayleigh transverse mode corresponding acoustic wave) with a frequency higher than the anti-resonance point of the first resonance, to reduce the spurious wave formed by the coupling between the acoustic wave with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave corresponding to the second resonance, and improve the communication performance. In addition, the acoustic speed of the part of the piezoelectric material layer 31 where the third dummy finger 332 is located is less than the acoustic speed of the part of the piezoelectric material layer 31 on the side of the third dummy finger 332 away from the transmission channel 323. Therefore, the acoustic wave (Rayleigh transverse mode corresponding acoustic wave) with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave (SH mode corresponding acoustic wave) corresponding to the second resonance will be scattered (e.g., reflected and / or refracted) on the piezoelectric material layer 31 near the third dummy finger 332, to prevent the coupling between the acoustic wave with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave corresponding to the second resonance, further reduce the spurious wave, and further improve the communication performance.

[0085] Continuing to refer to Figure 8In the above implementation, the transducer 32 further comprises a fourth dummy finger 338, the fourth dummy finger 338 is arranged between the second bus bar 322 and the first bus bar 321, and the fourth dummy finger 338 is connected with the second bus bar 322; that is, the fourth dummy finger 338 is arranged on the piezoelectric material layer 31, and the fourth dummy finger 338 is connected with the second bus bar 322. In this way, the sound speed of the part of the piezoelectric material layer 31 corresponding to the fourth dummy finger 338 can be reduced, so that the sound wave on the piezoelectric material layer 31 corresponding to the transmission channel 323 is reflected at the position where the fourth dummy finger 338 is located, and the leakage of the sound wave to the outside of the second bus bar 322 is prevented.

[0086] In some examples, the fourth dummy finger 338 can be arranged between the first insertion finger 324 and the second bus bar 322, and the fourth dummy finger 338 is arranged in a spaced manner with the first insertion finger 324. In a direction perpendicular to the length of the second bus bar 322, the projections of the fourth dummy finger 338 and the first insertion finger 324 on the second bus bar 322 can at least partially overlap, and of course the projections of the fourth dummy finger 338 and the first insertion finger 324 on the second bus bar 322 can also be arranged in a spaced manner.

[0087] In some examples, in a direction perpendicular to the length of the second bus bar 322, the projections of the third dummy finger 332 and the first insertion finger 324 on the second bus bar 322 can at least partially overlap, and of course the projections of the third dummy finger 332 and the first insertion finger 324 on the second bus bar 322 can also be arranged in a spaced manner. In a direction perpendicular to the length of the second bus bar 322, the projections of the third dummy finger 332 and the fourth dummy finger 338 on the first bus bar 321 can at least partially overlap.

[0088] For reference Figure 9 In the embodiments of the present application, the transducer 32 further comprises a first auxiliary dummy finger 334, the first auxiliary dummy finger 334 is arranged between the second bus bar 322 and the first bus bar 321, and the first insertion finger 324 is connected with the first bus bar 321 through the first auxiliary dummy finger 334. In this way, the sound speed of the part of the piezoelectric material layer 31 corresponding to the first auxiliary dummy finger 334 can be reduced, so that the sound wave on the piezoelectric material layer 31 corresponding to the transmission channel 323 is reflected at the position where the first auxiliary dummy finger 334 is located, and the leakage of the sound wave to the outside of the first bus bar 321 is prevented.

[0089] For example, in a direction parallel to the piezoelectric material layer 31 and parallel to the length of the first bus bar 321, the width of the first auxiliary dummy finger 334 is greater than the width of the first insertion finger 324. In this way, the sound speed of the part of the piezoelectric material layer 31 corresponding to the first auxiliary dummy finger 334 can be further reduced, and the leakage of the sound wave to the outside of the first bus bar 321 is further prevented.

[0090] It can be understood that the first auxiliary dummy finger 334 can be an integral structure with the first interdigital transducer finger 324, that is, the first auxiliary dummy finger 334 and the first interdigital transducer finger 324 are formed simultaneously by the same process. The first auxiliary dummy finger 334 and the first interdigital transducer finger 324 can be made of the same material, while the width of the first auxiliary dummy finger 334 is different from that of the first interdigital transducer finger 324, so that the first auxiliary dummy finger 334 corresponds to a lower acoustic velocity of the piezoelectric material layer 31, thereby facilitating reflection of the acoustic wave.

[0091] With reference to the foregoing description Figure 10 In the implementation mode in which the transducer 32 includes the first auxiliary bus bar 327 and the first connecting column 328, the transducer 32 further includes a second auxiliary dummy finger 335, which is arranged between the first auxiliary bus bar 327 and the first bus bar 321, and the first connecting column 328 is connected to the first bus bar 321 through the second auxiliary dummy finger 335. In this way, the second auxiliary dummy finger 335 can further increase the density of the side of the first bus bar 321 away from the second bus bar 322, further prevent the formation of the acoustic wave (the acoustic wave corresponding to the Rayleigh transverse mode) with a frequency higher than the anti-resonance point of the first resonance, and reduce the spurious wave formed by the coupling between the acoustic wave and the acoustic wave corresponding to the second resonance, thereby improving the communication performance. In addition, the acoustic velocity of the piezoelectric material layer 31 at the position of the second auxiliary dummy finger 335 is lower than that of the piezoelectric material layer 31 at the side of the first dummy finger 326 away from the transmission channel 323, so that the acoustic wave (the acoustic wave corresponding to the Rayleigh transverse mode) with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave (the acoustic wave corresponding to the SH mode) corresponding to the second resonance will be scattered (such as reflected and / or refracted) on the piezoelectric material layer 31 near the second auxiliary dummy finger 335, so as to prevent the coupling between the acoustic wave with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave corresponding to the second resonance, further reduce the spurious wave, and further improve the communication performance.

[0092] For example, in the direction parallel to the piezoelectric material layer 31 and parallel to the length of the first bus bar 321, the width of the second auxiliary dummy finger 335 is greater than the width of the first connecting column 328. In this way, the mass of the second auxiliary dummy finger 335 can be increased, the formation of the acoustic wave (the acoustic wave corresponding to the Rayleigh transverse mode) with a frequency higher than the anti-resonance point of the first resonance can be further prevented, and the reflection effect on the acoustic wave (the acoustic wave corresponding to the Rayleigh transverse mode) with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave (the acoustic wave corresponding to the SH mode) corresponding to the second resonance can be improved, so as to further prevent the coupling between the acoustic wave with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave corresponding to the second resonance.

[0093] With reference to the foregoing description Figure 10 and Figure 11In some embodiments, the transducer 32 further comprises a third auxiliary dummy finger 336 disposed between the first auxiliary bus bar 327 and the first bus bar 321, and the third auxiliary dummy finger 336 is connected to the first auxiliary bus bar 327. The third auxiliary dummy finger 336 is disposed apart from the first dummy finger 326. In this way, the acoustic velocity of the piezoelectric material layer 31 corresponding to the third auxiliary dummy finger 336 can be reduced, so that the acoustic wave can be scattered on the piezoelectric material layer 31 corresponding to the third auxiliary dummy finger 336, to prevent acoustic wave leakage. In addition, since the acoustic wave with a frequency higher than 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) are both scattered on the piezoelectric material layer 31 corresponding to the third auxiliary dummy finger 336, the acoustic wave with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave corresponding to the second resonance can be further prevented from being coupled.

[0094] For example, the projection of the third auxiliary dummy finger 336 and the first dummy finger 326 on the first bus bar 321 in a direction perpendicular to the length of the first bus bar 321 can at least partially overlap. Of course, the projection of the third auxiliary dummy finger 336 and the first dummy finger 326 on the first bus bar 321 can also be disposed apart.

[0095] For example, the projection of the third auxiliary dummy finger 336 and the first dummy finger 326 on the first bus bar 321 in a direction perpendicular to the length of the first bus bar 321 can at least partially overlap. Of course, the projection of the third auxiliary dummy finger 336 and the first dummy finger 326 on the first bus bar 321 can also be disposed apart. Figure 12 Figure 12 In some embodiments, the transducer 32 further comprises a fourth auxiliary dummy finger 337 disposed between the first auxiliary bus bar 327 and the first bus bar 321, and the fourth auxiliary dummy finger 337 is disposed apart from the first auxiliary bus bar 327 and the first bus bar 321. In this way, the acoustic velocity of the piezoelectric material layer 31 corresponding to the fourth auxiliary dummy finger 337 can be reduced, so that the acoustic wave can be scattered on the piezoelectric material layer 31 corresponding to the fourth auxiliary dummy finger 337, to prevent acoustic wave leakage. In addition, since the acoustic wave with a frequency higher than 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) are both scattered on the piezoelectric material layer 31 corresponding to the fourth auxiliary dummy finger 337, the acoustic wave with a frequency higher than the anti-resonance point of the first resonance and the acoustic wave corresponding to the second resonance can be further prevented from being coupled.

[0096] In some implementations, the fourth auxiliary dummy finger 337 can be located between the third auxiliary dummy finger 336 and the first dummy finger 326, and the fourth auxiliary dummy finger 337 is disposed apart from the third auxiliary dummy finger 336 and the first dummy finger 326. For example, the projection of the fourth auxiliary dummy finger 337 and the first dummy finger 326 on the first bus bar 321 in a direction perpendicular to the length of the first bus bar 321 can at least partially overlap. Of course, the projection of the fourth auxiliary dummy finger 337 and the first dummy finger 326 on the first bus bar 321 can also be disposed apart.​

[0097] Please refer to ​ In this embodiment, the transducer 32 further includes a fifth auxiliary pseudo-finger 339, which is disposed between the second busbar 322 and the first busbar 321. The second insertion finger 325 is connected to the second busbar 322 via 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 sound waves from leaking out of the second busbar 322.

[0098] 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.

[0099] 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.

[0100] Continue to refer to ​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 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 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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 by, The piezoelectric material layer comprises: a transducer disposed on a surface of the piezoelectric material layer, the transducer comprising: a first bus bar and a second bus bar disposed in parallel and spaced apart; a first finger and a second finger disposed in parallel and spaced apart between the first bus bar and the second bus bar, the first finger connected to the first bus bar, and the second finger connected to the second bus bar; a first dummy finger disposed on a side of the first bus bar away from the second bus bar, and the first dummy finger connected to the first bus bar. The transducer further comprises a second dummy finger disposed between the first bus bar and the second bus bar, and the second dummy finger connected to the first bus bar.

2. The surface acoustic wave resonator according to claim 1, characterized by The transducer further comprises a first auxiliary dummy finger disposed between the first bus bar and the second bus bar, and the first finger connected to the first bus bar through the first auxiliary dummy finger.

3. The surface acoustic wave resonator according to claim 1 or 2, characterized by, In a direction along a length of the first bus bar, a width of the first auxiliary dummy finger is greater than a width of the first finger.

4. The surface acoustic wave resonator according to claim 3, wherein The transducer further comprises a first auxiliary bus bar disposed on a side of the first bus bar away from the second bus bar, and the first auxiliary bus bar disposed in parallel and spaced apart from the first bus bar; and a first connecting column disposed between the first auxiliary bus bar and the first bus bar, one end of the first connecting column connected to the first auxiliary bus bar, and the other end of the first connecting column connected to the first bus bar.

5. The surface acoustic wave resonator according to any one of claims 1 to 4, characterized by The transducer further comprises a second auxiliary dummy finger disposed between the first auxiliary bus bar and the first bus bar, and the first connecting column connected to the first bus bar through the second auxiliary dummy finger.

6. The surface acoustic wave resonator according to claim 5, wherein In the direction along the length of the first bus bar, a width of the second auxiliary dummy finger is greater than a width of the first connecting column.

7. The surface acoustic wave resonator according to claim 6, wherein The transducer further comprises a third auxiliary dummy finger disposed between the first auxiliary bus bar and the first bus bar, and the third auxiliary dummy finger connected to the first auxiliary bus bar; and the third auxiliary dummy finger disposed in parallel and spaced apart from the first dummy finger.

8. The surface acoustic wave resonator according to claim 6 or 7, characterized by, The transducer further comprises a fourth auxiliary dummy finger disposed between the first auxiliary bus bar and the first bus bar, and the fourth auxiliary dummy finger disposed in parallel and spaced apart from both the first auxiliary bus bar and the first bus bar.

9. The surface acoustic wave resonator according to any one of claims 5 to 8, characterized by, The length direction of the first bus bar and the second bus bar is parallel, a distance between the first bus bar and the first auxiliary bus bar is 1.3L1-2.8L1, and a thickness of the first dummy finger in a direction parallel to the piezoelectric material layer and perpendicular to the length of the first bus bar is 0.1L1-0.4L1, where L1 is a shortest distance between a center line of the first finger and a center line of the second finger.

10. The surface acoustic wave resonator according to any one of claims 5 to 9, characterized by ​ 11. The surface acoustic wave resonator according to any one of claims 1 to 10, characterized by The width of the first dummy finger in the direction of the length of the first bus bar is greater than or equal to 0.4L1, wherein L1 is the shortest distance between the center line of the first insertion finger and the center line of the second insertion finger.

12. The surface acoustic wave resonator of claim 10, wherein, The width of the first dummy finger in the direction of the length of the first bus bar is less than or equal to 0.8L1; the first dummy finger has a first midpoint, the first insertion 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 by Comprising: A plurality of surface acoustic wave resonators, at least one of which is the surface acoustic wave resonator of any one of claims 1-12, at least two of the plurality of surface acoustic wave resonators being connected in series or in parallel.

14. A communication chip, comprising: Comprising: A radio frequency front-end circuit comprising a power amplifier and / or a low noise amplifier, the radio frequency front-end circuit being coupled to the filter.

15. An electronic device, comprising: Comprising: An antenna, and the communication chip of claim 14, the communication chip being coupled to the antenna. Comprising: An antenna, and the communication chip of claim 14, the communication chip being coupled to the antenna.

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