Elastic wave device and radio frequency front end module

Abstract

The invention discloses an elastic wave device and a radio frequency front-end module, which can weaken plate waves outside a passband of a surface acoustic wave filter while obtaining a better temperature compensation effect by adjusting the thickness of a temperature compensation layer of the surface acoustic wave filter, thereby improving the out-of-band rejection level of the surface acoustic wave filter and improving the performance of the surface acoustic wave filter. And in the CA state, the influence on the passband performance of other filters in the CA frequency band can be reduced, so that the CA performance is improved.

Description

Technical Field

[0001] This application relates to the field of radio frequency technology, and in particular to an elastic wave device and a radio frequency front-end module. Background Technology

[0002] Elastic wave devices, such as temperature-compensated surface acoustic wave filters, use a temperature compensation layer to adjust the frequency temperature coefficient of the device, thereby achieving temperature compensation. Generally, the thicker the temperature compensation layer, the better the temperature compensation effect.

[0003] In practical applications, it has been found that in some cases, temperature-compensated surface acoustic wave (SAW) filters can generate out-of-band plate waves. These waves not only leak the energy of the filter's main mode but also introduce spurious signals outside the band, thus degrading the filter's out-of-band suppression performance. This is especially true for filters with frequency band combinations that require carrier aggregation (CA), where out-of-band plate waves can cause significant degradation in CA performance.

[0004] Application content This application provides an elastic wave device and an RF front-end module that can improve the out-of-band rejection level of the surface acoustic wave filter and enhance the filter's CA performance while achieving better TCF.

[0005] In a first aspect, embodiments of this application provide an elastic wave device, comprising: A first filter and a second wave filter, wherein the first filter includes a piezoelectric substrate, at least two IDT electrodes located on one side of the piezoelectric substrate, and a temperature compensation layer, wherein the temperature compensation layer covers the at least two IDT electrodes; The passband of the first filter corresponds to the first frequency band, and the passband of the second filter corresponds to the second frequency band. The radio frequency signals of the first frequency band and the radio frequency signals of the second frequency band can be transmitted simultaneously. The center frequency of the passband of the first filter is f01, and the center frequency of the passband of the second filter is f02. The ratio of f02 to f01 is in the range of [1.2, 1.6]. The thickness of the temperature compensation layer of the first filter is H, and the thickness of the IDT electrode of the first filter is h. The ratio of H to h is in the range of (1, 3.5).

[0006] Secondly, embodiments of this application provide an elastic wave device, comprising: A first acoustic filter and a second filter, wherein the first filter includes a piezoelectric substrate, at least two IDT electrodes located on one side of the piezoelectric substrate, and a temperature compensation layer, wherein the temperature compensation layer covers the at least two IDT electrodes; The passband of the first filter corresponds to the first frequency band, and the passband of the second filter corresponds to the second frequency band. The radio frequency signals of the first frequency band and the radio frequency signals of the second frequency band can be transmitted simultaneously. The thickness H of the temperature compensation layer of the first filter is configured to attenuate the plate wave outside the passband of the first filter, and the frequency point corresponding to the plate wave is located within the passband of the second filter.

[0007] Thirdly, embodiments of this application provide an elastic wave device, comprising: A surface acoustic wave (SAW) filter, comprising a piezoelectric substrate, at least two independent thermal detachment (IDT) electrodes located on one side of the piezoelectric substrate, and a temperature compensation layer covering the at least two IDT electrodes; The thickness H of the temperature compensation layer is configured to attenuate the plate wave outside the passband of the surface acoustic wave filter, and the frequency point corresponding to the plate wave is located in the range of 1.2 to 1.6 times the resonant frequency fr of the main mode of the surface acoustic wave filter.

[0008] Fourthly, embodiments of this application provide a radio frequency front-end module, including the elastic wave device provided in any one of the first, second, and third aspects of this application.

[0009] The elastic wave device and RF front-end module provided in this application embodiment can reduce the plate wave outside the passband of the surface acoustic wave filter while achieving a better temperature compensation effect by adjusting the thickness of the temperature compensation layer of the surface acoustic wave filter. This can improve the out-of-band suppression level of the surface acoustic wave filter. Furthermore, in CA state, it can also reduce the impact on the passband performance of other filters in the CA band, thereby improving CA performance. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the structure of the temperature-compensated surface acoustic wave resonator provided in the embodiments of this application; Figure 2 This is a schematic cross-sectional view of the temperature-compensated surface acoustic wave resonator provided in the embodiments of this application; Figure 3 This is a schematic diagram of the circuit structure of the surface acoustic wave filter provided in the embodiments of this application; Figure 4This is a schematic diagram of the elastic wave device provided in an embodiment of this application; Figure 5 This is another structural schematic diagram of the elastic wave device provided in the embodiments of this application; Figure 6 These are an admittance diagram and an energy distribution diagram of the temperature-compensated surface acoustic wave resonator provided in the embodiments of this application; Figure 7 This is another admittance diagram and energy distribution diagram of the temperature-compensated surface acoustic wave resonator provided in the embodiments of this application; Figure 8 This is another admittance diagram and energy distribution diagram of the temperature-compensated surface acoustic wave resonator provided in the embodiments of this application; Figure 9 This is a comparison chart of the frequency offset of surface acoustic wave filters with temperature compensation layers of different thicknesses provided in the embodiments of this application at different temperatures relative to room temperature; Figure 10 This is an admittance diagram of the temperature-compensated surface acoustic wave resonator provided in the embodiments of this application; Figure 11 These are the impedance distribution diagram of the first filter in the CA band and the passband diagram of the second filter in related technologies. Figure 12 These are the impedance distribution diagram of the first filter in the CA band and the passband diagram of the second filter provided in the embodiments of this application.

[0012] Explanation of icon numbers: 100 / 100a / 100b, temperature-compensated surface acoustic wave resonator; 10 / 10a / 10b, piezoelectric substrate; 11, piezoelectric layer; 12, substrate; 20. IDT electrode; 30. Reflective grating; 40. Temperature compensation layer; 1000, Surface Acoustic Wave Filter; 1000a, First Filter; 1000b, Second Filter; IN, input terminal; OUT, output terminal; GND, ground terminal. Detailed Implementation

[0013] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0014] The following descriptions of the embodiments are based on the accompanying illustrations and are used to illustrate specific embodiments in which this application can be implemented. The component designations used herein, such as "first," "second," etc., are merely for distinguishing the described objects and have no sequential or technical meaning. Unless otherwise specified, the terms "connection" and "linkage" used in this application include both direct and indirect connections (linkages). Directional terms used in this application, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "side," etc., are merely for reference to the accompanying illustrations. Therefore, the use of directional terms is for better and clearer explanation and understanding of this application, and does not indicate or imply that the referred device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this application.

[0015] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising," "may include," "include," or "may contain" used in this application indicate the existence of the corresponding disclosed functions, operations, elements, etc., and do not limit other one or more additional functions, operations, elements, etc.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0017] A resonator is the smallest unit of an acoustic wave filter. Multiple resonators are connected in series and parallel to form a filter, which filters out unwanted radio frequency (RF) signals and allows desired RF signals to pass through, thus performing a filtering function. Resonators are generally divided into surface acoustic wave (SAW) resonators and bulk acoustic wave (SAW) resonators (including thin-film SAW resonators). SAW resonators include ordinary SAW resonators, temperature-compensated SAW resonators, and thin-film SAW resonators with multilayer substrate structures, etc.

[0018] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a temperature-compensated surface acoustic wave resonator. Figure 2 This is a schematic diagram of the cross-sectional structure of a temperature-compensated surface acoustic wave resonator. Figure 1 In this embodiment, the temperature-compensated surface acoustic wave resonator 100 includes a piezoelectric substrate 10, an IDT electrode 20 located on one side of the piezoelectric substrate, and two reflective gratings 30. The IDT electrode 20 is located between the two reflective gratings 30, and a temperature compensation layer 40 at least covers the IDT electrode 20. In one embodiment, the temperature compensation layer 40 may also cover the reflective gratings 30 (not shown in the figure). The temperature-compensated surface acoustic wave resonator 100 thereby adjusts the frequency temperature coefficient of the device through the temperature compensation layer 40 to achieve temperature compensation.

[0019] Specifically, the IDT electrode 20 includes two busbars and multiple electrode fingers. The two busbars extend along the X direction and are arranged opposite each other and spaced apart along the Y direction. The multiple electrode fingers are located between the two busbars and are also spaced apart along the X direction. Of the multiple electrode fingers, one end of one portion is connected to one of the busbars, and the other end extends towards the other busbar and is spaced apart from it; the other portion of the electrode fingers do the opposite. The electrode fingers connected to different busbars are alternately arranged along the X direction.

[0020] It is understood that the extension direction (X direction) of the busbar is orthogonal to the length direction (Y direction) of the electrode finger. In other embodiments, the extension direction of the busbar and the length direction of the electrode finger may intersect rather than be orthogonal, for example, the busbar may be inclined. This application embodiment is not limited to this.

[0021] It should be noted that the embodiments of this application can be applied to the structure of a temperature-compensated surface acoustic wave resonator with directly pointing electrode fingers, such as... Figure 1 As shown in (a), it can also be applied to the structure of temperature-compensated surface acoustic wave resonators with bent electrode fingers, such as... Figure 1 As shown in (b), the embodiments of this application are not specifically limited. The temperature-compensated surface acoustic wave resonator 100 in this application may be provided with a mass load structure, such as widening, thickening, or adding metal strips on both sides of the area where the electrode fingers overlap along the Y direction, which can reduce the sound velocity in the area where the structure is located. The embodiments of this application will not elaborate on this.

[0022] In practical applications, when the temperature compensation layer is thin, the resonator's frequency shift is large at high and low temperatures, and the temperature compensation effect is poor. As the thickness of the temperature compensation layer increases, the frequency shift of the resonator decreases at high and low temperatures, and the temperature compensation effect is better.

[0023] However, when the temperature compensation layer is thin, the energy constraint of the bulk wave scattered from the piezoelectric substrate to the temperature compensation layer in a temperature-compensated surface acoustic wave resonator is weak, making it difficult to form spurious modes or resulting in weak spurious modes and low Q values. When the temperature compensation layer reaches a certain thickness, the speed of sound propagation in air is less than that within the temperature compensation layer, and the speed of sound propagation within the temperature compensation layer is less than that within the piezoelectric substrate. This distribution of sound speeds makes the temperature compensation layer a natural acoustic waveguide. When a specific bulk acoustic wave excited in the piezoelectric substrate meets specific phase conditions, energy radiates from the piezoelectric substrate to the temperature compensation layer, accumulating energy to form a plate wave. The formation of the plate wave not only leaks the energy of the dominant mode but also introduces spurious modes at the high-frequency side of the resonant frequency fr. When applied to filters, this introduces spurious signals outside the band, leading to a deterioration in the filter's out-of-band rejection performance. Especially for filters with frequency band combinations requiring CA (Clearance Control), if the out-of-band plate wave of one filter falls into the passband of another filter, it will significantly degrade the CA performance of that other filter.

[0024] To address the aforementioned issues, embodiments of this application provide an elastic wave device and an RF front-end module, which can improve the out-of-band rejection level of the filter and enhance CA performance.

[0025] This application provides an elastic wave device, which includes a surface acoustic wave filter. Figure 3 An exemplary circuit structure diagram of a surface acoustic wave filter is shown. Figure 3 As shown, the surface acoustic wave filter 1000 includes an input terminal IN, an output terminal OUT, a ground terminal GND, and five temperature-compensated surface acoustic wave resonators 100. Three of the temperature-compensated surface acoustic wave resonators 100 are connected in series between the input terminal IN and the output terminal OUT. One end of the other two temperature-compensated surface acoustic wave resonators 100 is connected to different nodes in the series branch, and the other end is connected to the ground terminal GND.

[0026] It is understood that in the surface acoustic wave filter provided in this application embodiment, the number and connection method of the temperature-compensated surface acoustic wave resonators 100 are not limited to the circuit structure shown in the figure. For example, the temperature-compensated surface acoustic wave resonators 100 connected in parallel to ground can share a common ground or not share a common ground.

[0027] In other embodiments, the surface acoustic wave (SAW) filter may further include one, two, or more temperature-compensated longitudinally coupled resonators. Each temperature-compensated longitudinally coupled resonator has two or more IDT electrodes spaced between two reflective gratings. A temperature compensation layer covers these IDT electrodes and the reflective gratings. Examples include dual-mode SAW filters (also known as DMS) and multi-mode SAW filters. The two or more temperature-compensated longitudinally coupled resonators can be connected in parallel or in series with the series branch of the SAW filter; this application does not limit this specific connection.

[0028] In this embodiment, the surface acoustic wave (SAW) filter includes a piezoelectric substrate 10, at least two individual thermal detachable (IDT) electrodes 20 located on one side of the piezoelectric substrate 10, and a temperature compensation layer 40 covering the at least two IDT electrodes 20. That is, the SAW filter includes multiple temperature-compensated SAW resonators and / or temperature-compensated longitudinally coupled resonators that share the same piezoelectric substrate 10, for example... Figure 4 In the first surface acoustic wave filter 100a, multiple temperature-compensated surface acoustic wave resonators 100a share the same piezoelectric substrate 10a, or in the second surface acoustic wave filter 1000b, multiple temperature-compensated surface acoustic wave resonators 100b share the same piezoelectric substrate 10b.

[0029] The thickness H of the temperature compensation layer 40 is configured to attenuate the plate wave outside the passband of the surface acoustic wave filter, the plate wave corresponding to a frequency point in the range of 1.2 to 1.6 times the resonant frequency fr of the main mode of the modified surface acoustic wave filter.

[0030] It is understandable that in a surface acoustic wave (SAW) filter, the structures of the resonators can be the same or different. For example, the electrode fingers of some resonators may use different designs. Figure 1 (a) shows a direct pointing structure, while the electrodes of the other part of the resonator use... Figure 1 The bent finger structure shown in (b) is not limited in this application embodiment.

[0031] In this embodiment, the thickness of the temperature compensation layer 40 in the surface acoustic wave filter 1000 is adjusted so that the surface acoustic wave filter 1000 can obtain a better temperature coefficient of frequency (TCF) while weakening the plate wave with a frequency point in the range of 1.2fr-1.6fr of the main mode. This plate wave is outside the passband of the surface acoustic wave filter, thereby improving the out-of-band suppression level of the surface acoustic wave filter.

[0032] In one embodiment, the material of the temperature compensation layer 40 may be at least one of dielectric materials with a positive temperature compensation coefficient, such as silicon oxide, silicon nitride, silicon oxynitride, tellurium dioxide, and silicon oxyfluoride.

[0033] In another embodiment, the side of the temperature compensation layer 40 facing away from the piezoelectric substrate 10 may also be covered with a passivation layer and / or a frequency modulation layer (not shown in the figure) to protect the IDT electrode 20 and / or to modulate the temperature-compensated surface acoustic wave resonator 100. The material of the passivation layer and / or the frequency modulation layer may be at least one of silicon dioxide, silicon nitride, silicon oxynitride, aluminum nitride, and aluminum oxide.

[0034] In one embodiment, the piezoelectric substrate 10 of the surface acoustic wave filter 1000 may include a piezoelectric layer 11, and an IDT electrode 20 is disposed on a layer of the piezoelectric layer 11, such as... Figure 2 As shown in (a), Figure 2 (a) An exemplary illustration shows that the IDT electrode 20 is disposed on one side of the piezoelectric layer 11. The piezoelectric layer 11 can be a single layer or multiple layers of piezoelectric materials with piezoelectric properties, such as aluminum nitride, zinc oxide, lead zirconate titanate (PZT), or rare earth element doping materials disposed in the above materials at a certain atomic ratio; single-crystal piezoelectric materials can also be selected, such as single-crystal aluminum nitride, lithium niobate, lithium tantalate, quartz, etc., which are not limited in this embodiment. Preferably, the material of the piezoelectric layer is lithium niobate.

[0035] In another embodiment, the piezoelectric substrate 10 of the temperature-compensated surface acoustic wave resonator 100 may include a piezoelectric layer 11 and a substrate 12 stacked in the thickness direction (i.e., the Z direction) of the IDT electrode 20, with the IDT electrode 20 disposed on the side of the piezoelectric layer 11 facing away from the substrate 12, such as... Figure 2 As shown in (b), Figure 2 (b) An exemplary illustration shows that the IDT electrode 20 is disposed on the side of the piezoelectric layer 11 facing away from the substrate 12. For example... Figure 2 In (b), high and low acoustic impedance layers may be alternately disposed between the piezoelectric layer 11 and the substrate 12. The substrate 12 may be made of materials such as silicon, quartz, sapphire, and silicon carbide, and is not limited to any particular material in this embodiment. The piezoelectric layer 11 is preferably made of lithium niobate.

[0036] In the embodiments of this application, the materials of the IDT electrode 20 and the reflective grid 30 can be a single metal material or a composite or alloy of different metals. Optionally, the aforementioned materials can be one of aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, or a composite or alloy of the above metals. The materials of the IDT electrode 20 and the reflective grid 30 can be the same or different. The IDT electrode 20 and the reflective grid 30 can be a single-layer metal film or a stacked metal film with multiple metal layers. The embodiments of this application are not limited.

[0037] In a preferred embodiment, the thickness of the temperature compensation layer 40 in the surface acoustic wave filter 1000 is adjusted so that it can weaken the plate wave with a frequency point in the range of 1.3fr-1.5fr of the main mode. This further weakens the plate wave and improves the out-of-band suppression level of the surface acoustic wave filter, while also achieving a better TCF so that the frequency shift of the surface acoustic wave filter 1000 is small when the temperature changes.

[0038] In one embodiment, the thickness of the IDT electrode 20 is h, and the ratio of the thickness H of the temperature compensation layer 40 to h is in the range of (1, 3.5).

[0039] Specifically, H / h can be 1.2, 1.5, 1.7, 2, 2.4, 2.8, 3.1, 3.5, etc. By adjusting the thickness H of the temperature compensation layer 40 in the surface acoustic wave filter 1000 so that its ratio to the thickness of the IDT electrode finger is within the range of (1, 3.5], while obtaining a better TCF, the plate waves outside the passband of the surface acoustic wave filter 1000 can be effectively weakened, especially the plate waves with frequency points located in the range of 1.3fr-1.5fr of the main mode resonant frequency, thereby further improving the out-of-band suppression level of the surface acoustic wave filter 1000 and enhancing the working performance of the surface acoustic wave filter 1000.

[0040] Please see Figure 6-Figure 8 , Figure 6-Figure 8 The figures shown are admittance diagrams and energy distribution diagrams for a temperature-compensated surface acoustic wave resonator 100. Figure 6-Figure 8 In the figure, (a) is the admittance diagram, with the horizontal axis representing frequency and the vertical axis representing admittance, in dBm; and (b) is the energy distribution diagram.

[0041] exist Figure 6 In the temperature-compensated surface acoustic wave resonator 100, the ratio of the thickness of the temperature compensation layer 40 to the thickness of the IDT electrode 20 is 2. As shown in the red box in Figure (b), the volume wave energy formed from the piezoelectric substrate is weak (red indicates higher energy, blue indicates lower energy). The temperature compensation layer cannot accumulate energy well to form a stray mode. The amplitude of the plate wave on the right side of the resonant frequency in Figure (a) is small.

[0042] exist Figure 7 In the temperature-compensated surface acoustic wave resonator 100, the ratio of the thickness of the temperature compensation layer 40 to the thickness of the IDT electrode 20 is 3.5. As shown in the red box in figure (b), some energy has already radiated from the piezoelectric substrate to the temperature compensation layer, but the overall amplitude is small. It can be seen that the plate wave formed on the right side of the resonant frequency in figure (a) is relatively small. Figure 6 The amplitude has increased.

[0043] exist Figure 8In the temperature-compensated surface acoustic wave resonator 100, the ratio of the thickness of the temperature compensation layer 40 to the thickness of the IDT electrode 20 is 4. As shown in the red box in Figure (b), energy is radiated from the piezoelectric substrate to the temperature compensation layer, and a relatively obvious stray mode is formed. It can be seen that the plate wave amplitude to the right of the resonant frequency in Figure (a) is significantly increased.

[0044] Please also refer to Figure 9 , Figure 9 This refers to the frequency shift of surface acoustic wave filters with temperature compensation layers of different thicknesses relative to room temperature at different temperatures. Figure 9 In the diagram, the horizontal axis represents temperature in °C, and the vertical axis represents... The values ​​represent the frequency shift relative to room temperature at different temperatures, in MHz. The red line indicates the frequency shift when the ratio of the temperature compensation layer thickness H to the IDT electrode thickness h is 3.7. The blue line represents the variation when the ratio of the temperature compensation layer thickness H to the IDT electrode thickness h is 3.3. The changes in . Among them, Figure 9 In the diagram, G0 corresponds to room temperature (25℃), G1 to -35℃, and G2 to 85℃. At point G1, the blue line represents a frequency shift of 4MHz relative to G0, and the red line represents a frequency shift of 3.2MHz relative to G0. At point G2, the blue line represents a frequency shift of -4MHz relative to G0, and the red line represents a frequency shift of -3.2MHz relative to G0. This demonstrates that as the thickness of the temperature compensation layer increases, the frequency shift of the surface acoustic wave filter relative to room temperature decreases under both high and low temperature conditions.

[0045] Depend on Figure 6-Figure 8 The comparison shows that the thicker the temperature compensation layer 40, the larger the amplitude of the plate wave and the more energy leakage of the main mode. However, when the ratio of the thickness of the temperature compensation layer 40 to the thickness of the IDT electrode 20 is less than 1, it may not meet the resonator's TCF requirements. Figure 9 The comparison shows that the thicker the temperature compensation layer 40, the smaller the frequency shift. Therefore, limiting the thickness H of the temperature compensation layer 40 to a ratio of the thickness h of the IDT electrode within the range of (1, 3.5) helps to reduce the amplitude of the plate wave in the frequency range of 1.2fr-1.6fr while taking into account the TCF. Applying this resonator to a surface acoustic wave filter can improve the out-of-band rejection level of the surface acoustic wave filter.

[0046] In a preferred embodiment, when the main component of the material of the IDT electrode 20 is copper, the ratio of the thickness H of the temperature compensation layer 40 to the thickness h of the IDT electrode 20 is in the range of [2.5, 3.5].

[0047] Specifically, the H / h ratio can be 2.5, 2.8, 3, 3.2, 3.5, etc.

[0048] Please also refer to Figure 10 , Figure 10 This diagram illustrates the plate wave amplitude variation of a temperature-compensated surface acoustic wave (SAW) resonator with different temperature compensation layer thicknesses. The horizontal axis represents frequency, and the vertical axis represents admittance in dBm. In the SAW resonator, the main material of the IDT electrode 20 is copper. With a fixed thickness h of the IDT electrode 20, increasing the thickness H of the temperature compensation layer 40 yields admittance diagrams for resonators with different temperature compensation layer thicknesses, as shown below. Figure 10 As shown, the area within the red dashed box represents the plate wave. The dark blue, green, red, sky blue, and magenta lines (from left to right within the dashed box) represent the admittance curves of the temperature-compensated surface acoustic wave resonator when the ratio of the thickness H of the temperature compensation layer 40 to the thickness h of the IDT electrode 20 is 2.2, 2.9, 3.7, 4.4, and 5.2, respectively. It can be seen that the thicker the temperature compensation layer H, the stronger the plate wave amplitude. Considering the overall effect of temperature compensation, its application in filters can achieve both better TCF and improved out-of-band rejection.

[0049] In this embodiment, when the main component of the IDT electrode material is copper, adjusting the thickness of the temperature compensation layer to be within the range of [2.5, 3.5] as the ratio to the thickness of the IDT electrode can effectively weaken the plate wave with frequency points in the range of 1.3fr-1.5fr of the main mode. This can not only obtain a better TCF, but also further improve the out-of-band suppression level of the surface acoustic wave filter.

[0050] In another preferred embodiment, if the main component of the material of the IDT electrode 20 is another metal, such as if the ratio of the density of the metal to the density of copper is a, the ratio of the thickness H of the temperature compensation layer 40 to the thickness h of the IDT electrode 20 is in the range of [2.5 / a, 3.5 / a].

[0051] Specifically, taking copper as the main component of the IDT electrode 20 material as a benchmark, if the main component is another metal, the ratio range of the thickness H of the temperature compensation layer 40 to the thickness h of the IDT electrode 20 can be calculated based on the density relationship with metallic copper. Assuming the main component of the IDT electrode 20 material is metallic Y, and the ratio of the density of metallic Y to the density of copper is approximately 1.3, then the upper limit of the ratio of the thickness H of the temperature compensation layer 40 to the thickness h of the IDT electrode 20 can be 3.5 / 1.3≈2.69, and the lower limit can be 2.5 / 1.3≈1.92.

[0052] Therefore, this method can be used to obtain the optimal film thickness of the temperature compensation layer when the IDT electrode of the surface acoustic wave filter is made of different materials. This can achieve better TCF while effectively reducing plate waves with frequency points in the 1.3fr-1.5fr range of the main mode, thereby further improving the out-of-band suppression level of the surface acoustic wave filter.

[0053] For example, when the main component of the material of the IDT electrode 20 is molybdenum, since the density ratio of metallic molybdenum to metallic copper is about 1.14, the ratio of the thickness H of the temperature compensation layer 40 to the thickness h of the IDT electrode 20 is in the range of [2.2, 3.1].

[0054] Specifically, the H / h ratio can be 2.2, 2.3, 2.5, 2.8, 3, 3.1, etc.

[0055] In this embodiment, when the main component of the IDT electrode material is molybdenum, adjusting the thickness of the temperature compensation layer to a ratio of approximately [2.2, 3.1] to the thickness of the IDT electrode can effectively weaken plate waves with frequencies in the range of 1.3fr-1.5fr of the main mode. This not only achieves better TCF but also further improves the out-of-band suppression level of the surface acoustic wave filter.

[0056] In one embodiment, the relative bandwidth of the surface acoustic wave filter is less than or equal to 7%, and the ratio of the thickness H of the temperature compensation layer 40 to the thickness h of the IDT electrode 20 is in the range of [2.2, 3.5].

[0057] It is understandable that the ratio of H to h can be 2, 2.5, 2.8, 3, 3.3, 3.5, etc. When the surface acoustic wave filter has a small bandwidth, adjusting the thickness of its temperature compensation layer 40 to this range can both meet the requirements of TCF and further improve the out-of-band suppression level of the surface acoustic wave filter.

[0058] In another embodiment, the relative bandwidth of the surface acoustic wave filter is greater than 7%, and the ratio of the thickness H of the temperature compensation layer 40 to the thickness h of the IDT electrode 20 is in the range of (1, 2.2).

[0059] Understandably, the ratio of H to h can be 1.2, 1.5, 1.8, 2, 2.1, etc. When the surface acoustic wave filter has a large bandwidth, adjusting the thickness of its temperature compensation layer 40 to this range can both meet the requirements of TCF and further improve the out-of-band suppression level of the surface acoustic wave filter.

[0060] In one embodiment, the thickness H of the temperature compensation layer 40 of the surface acoustic wave filter is in the range of [300 nm, 1600 nm].

[0061] It is understandable that the thickness H of the temperature compensation layer 40 can be 300nm, 500nm, 700nm, 1000nm, 1300nm, 1600nm, etc. Adjusting the thickness H of the temperature compensation layer within this range, especially ensuring that the ratio of H to the thickness h of the IDT electrode is within the range of (1, 3.5), can both meet the requirements of TCF and further improve the out-of-band suppression level of the surface acoustic wave filter.

[0062] In another embodiment, the thickness h of the IDT electrode 20 of the surface acoustic wave filter is in the range of [0.07λ, 0.1λ].

[0063] It is understandable that the thickness h of the IDT electrode 20 can be 0.07λ, 0.08λ, 0.09λ, 0.1λ, etc. Within this range, adjusting the thickness of the temperature compensation layer 40, especially ensuring that the ratio of the thickness H of the temperature compensation layer to the thickness h of the IDT electrode is within the range of (1, 3.5), can achieve good passband performance while also meeting the requirements of the TCF and further improving the out-of-band suppression level of the surface acoustic wave filter.

[0064] In another embodiment, the thickness of the piezoelectric layer 11 is in the range of [100 nm, 500 nm].

[0065] It is understandable that the thickness of the piezoelectric layer 11 can be 100nm, 120nm, 150nm, 180nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, etc. The material of the piezoelectric layer 11 can be lithium niobate. Within this range, adjusting the thickness of the temperature compensation layer, especially making the ratio of the thickness H of the temperature compensation layer 40 to the thickness h of the IDT electrode 20 within the range of (1, 3.5), can achieve good passband performance while also meeting the requirements of TCF and further improving the out-of-band suppression level of the surface acoustic wave filter.

[0066] In this embodiment, the thickness of the temperature compensation layer in the surface acoustic wave filter is adjusted so that it can achieve a better TCF and reduce the amplitude of the plate wave whose frequency point is in the range of 1.2 to 1.6 times the resonant frequency fr of the main mode of the surface acoustic wave filter. The plate wave is located outside the passband of the surface acoustic wave filter, thereby achieving both temperature compensation effect and improving the out-of-band suppression level of the surface acoustic wave filter.

[0067] Please see Figure 4 and Figure 5This application also provides an elastic wave device, which includes at least two filters: a first filter 1000a and a second filter 1000b. The first filter 1000a includes a piezoelectric substrate 10, at least two IDT electrodes located on one side of the piezoelectric substrate, and a temperature compensation layer covering the at least two IDT electrodes. The passband of the first filter 1000a corresponds to a first frequency band, and the passband of the second filter 1000b corresponds to a second frequency band. Radio frequency signals in the first and second frequency bands can be transmitted simultaneously. The center frequency of the passband of the first filter 1000a is f01, and the center frequency of the passband of the second filter 1000b is f02, with the ratio of f02 to f01 in the range [1.2, 1.6]. The thickness of the temperature compensation layer of the first filter 1000a is H, and the thickness of the IDT electrodes of the first filter 1000a is h, with the ratio of H to h in the range (1, 3.5).

[0068] It should be noted that, Figure 4 and Figure 5 The layout structure of the first filter 1000a and the second filter 1000b is shown as an example, but the embodiments of this application are not limited thereto.

[0069] It is understood that the first filter 1000a is a surface acoustic wave (SAW) filter, specifically a SAW filter including a temperature-compensated SAW resonator. The second filter 1000b can be a SAW filter, such as a SAW filter including a conventional SAW resonator, or a SAW filter including a temperature-compensated SAW resonator, or a bulk acoustic wave (BAS) filter (including a thin-film BAS filter), or an LC filter or a ceramic filter, etc., which are not limited in the embodiments of this application.

[0070] Specifically, the first filter 1000a can be a receiving filter or a transmitting filter, and the second filter 1000b can be a receiving filter or a transmitting filter; the embodiments of this application do not limit this.

[0071] In this embodiment of the application, the first frequency band corresponding to the passband of the first filter 1000a is the operating frequency band of the first filter 1000a, which allows radio frequency signals with frequencies within the first frequency band to pass through while filtering out radio frequency signals outside the first frequency band. The second frequency band corresponding to the passband of the second filter 1000b is the operating frequency band of the second filter 1000b, which allows radio frequency signals with frequencies within the second frequency band to pass through while filtering out radio frequency signals outside the second frequency band.

[0072] Specifically, the first filter 1000a and the second filter 1000b are two filters for carrier aggregation, and the first frequency band corresponds to the second frequency band, which is a combination of frequency bands that meet the requirements of carrier aggregation. In other words, the first filter 1000a and the second filter 1000b can work simultaneously, so that radio frequency signals with frequencies in the first frequency band and radio frequency signals with frequencies in the second frequency band can be transmitted simultaneously.

[0073] In this embodiment, the relationship between the first filter 1000a and the second filter 1000b is that the frequency of the first frequency band is less than the frequency of the second frequency band. Specifically, the ratio of the center frequency f01 of the passband of the first filter 1000a to the center frequency f02 of the passband of the second filter 1000b can be 1.2, 1.3, 1.4, 1.5, 1.6, etc., and is not limited in this embodiment.

[0074] In this embodiment, in the first filter 1000a and the second filter 1000b with carrier aggregation requirements, the first filter 1000a is a temperature-compensated surface acoustic wave filter. When the ratio of the center frequency f01 of the passband of the first filter 1000a to the center frequency f02 of the passband of the second filter 1000b is in the range of [1.2, 1.6], by adjusting the thickness of the temperature compensation layer of the first filter 1000a so that its ratio with the thickness of the IDT electrode is in the range of (1, 3.5), the plate wave of the first filter 1000a located in the passband of the second filter 1000b can be weakened. While meeting the TCF requirement of the first filter, this not only helps to improve the out-of-band suppression level of the first filter 1000a, but also reduces the impact on the passband performance of the second filter 1000b in CA state, thereby improving the CA performance of the elastic wave device.

[0075] In a preferred embodiment, the ratio of f02 to f01 is in the range of [1.3, 1.5].

[0076] In this embodiment, when the ratio of the center frequency f01 of the passband of the first filter 1000a to the center frequency f02 of the passband of the second filter 1000b is within the range of [1.3, 1.5], by adjusting the thickness of the temperature compensation layer of the first filter 1000a so that its ratio to the thickness of the IDT electrode is within the range of (1, 3.5], the amplitude of the plate wave of the first filter 1000a can be reduced. The frequency point corresponding to the plate wave is located within the passband of the second filter 1000b. While meeting the TCF requirements of the first filter, this not only helps to improve the out-of-band suppression level of the first filter 1000a, but also reduces the impact on the passband performance of the second filter 1000b under CA conditions, thereby improving the CA performance of the elastic wave device.

[0077] In a preferred embodiment, when the main component of the material of the IDT electrode 20 of the first filter 1000a is copper, the ratio of the thickness H of the temperature compensation layer 40 of the first filter 1000a to the thickness h of the IDT electrode 20 is in the range of [2.5, 3.5].

[0078] In this embodiment of the application, when the main component of the IDT electrode material is copper, adjusting the thickness of the temperature compensation layer to a ratio of [2.5, 3.5] to the thickness of the IDT electrode can effectively weaken the plate wave of the first filter 1000a, thereby achieving better TCF and, in CA state, further reducing the passband effect on the second filter 1000b and improving CA performance.

[0079] In another preferred embodiment, if the main component of the material of the IDT electrode 20 of the first filter 1000a is another metal, such as if the ratio of the density of the metal to the density of copper is a, the ratio of the thickness H of the temperature compensation layer 40 of the first filter 1000a to the thickness h of the IDT electrode 20 is in the range of [2.5 / a, 3.5 / a].

[0080] This method allows us to obtain the optimal film thickness of the temperature compensation layer when the IDT electrode of the surface acoustic wave filter is made of different materials. This not only achieves better TCF, but also effectively reduces the plate wave of the first filter 1000a. In CA state, it can further reduce the passband effect on the second filter 1000b and improve CA performance.

[0081] For example, when the main component of the material of the IDT electrode 20 of the first filter 1000a is molybdenum, since the density ratio of metallic molybdenum to metallic copper is about 1.14, the ratio of the thickness H of the temperature compensation layer 40 of the first filter 1000a to the thickness h of the IDT electrode 20 is in the range of [2, 3].

[0082] In this embodiment of the application, when the main component of the IDT electrode material is molybdenum, adjusting the thickness of the temperature compensation layer to a ratio of approximately [2.2, 3.1] to the thickness of the IDT electrode can effectively reduce the plate wave of the first filter 1000a, thereby achieving better TCF and, in CA state, further reducing the passband effect on the second filter 1000b and improving CA performance.

[0083] In one implementation, the relative bandwidth of the first filter 1000a is less than or equal to 7%, and the ratio of H to h is in the range of [2.2, 3.5].

[0084] In this embodiment of the application, when the first filter 1000a has a small bandwidth, the thickness of its temperature compensation layer is adjusted to this range, which can not only meet the requirements of TCF, but also further reduce the passband impact on the second filter 1000b and improve the CA performance in CA state.

[0085] In another implementation, the relative bandwidth of the first filter 1000a is greater than 7%, and the ratio of H to h is in the range of (1, 2.2).

[0086] With the first filter 1000a having a large bandwidth, adjusting the thickness of its temperature compensation layer to this range can both meet the requirements of TCF and further reduce the passband impact on the second filter 1000b under CA conditions, thereby improving CA performance.

[0087] In one exemplary embodiment, the passband of the first filter 1000a corresponds to a first frequency band with a frequency range of 1805Hz-1880Hz, and the passband of the second filter 1000b corresponds to a second frequency band with a frequency range of 2496Hz-2690Hz.

[0088] In another exemplary embodiment, the passband of the first filter 1000a corresponds to a first frequency band with a frequency range of 2110Hz-2170Hz, and the passband of the second filter 1000b corresponds to a second frequency band with a frequency range of 2496Hz-2690Hz.

[0089] In yet another exemplary embodiment, the passband of the first filter 1000a corresponds to a first frequency band with a frequency range of 1990Hz-1920Hz, and the passband of the second filter 1000b corresponds to a second frequency band with a frequency range of 2496Hz-2690Hz.

[0090] In this embodiment, when the radio frequency signal of the first frequency band and the radio frequency signal of the second frequency band are transmitted simultaneously, the thickness H of the temperature compensation layer of the first filter 1000a is adjusted so that the ratio of it to the thickness h of the IDT electrode satisfies (1, 3.5). This allows for the achievement of better TCF while reducing the influence of the plate wave of the first filter 1000a on the second filter 1000b, thereby improving CA performance.

[0091] It is understood that when both the first filter 1000a and the second filter 1000b are surface acoustic wave (SAW) filters, the second filter 1000b also includes a piezoelectric substrate and at least two IDT electrodes located on one side of the piezoelectric substrate. Optionally, the second filter 1000b may also include a temperature compensation layer covering the at least two IDT electrodes.

[0092] In one embodiment, the first filter 1000a and the second filter 1000b share the same piezoelectric substrate 10, such as Figure 5 As shown, the dashed box on the left represents the first filter 1000a, and the dashed box on the right represents the second filter 1000b. The two filters are fabricated on the same wafer, which reduces the chip size.

[0093] In another embodiment, the piezoelectric substrate 10a of the first filter 1000a and the piezoelectric substrate 10b of the second filter 1000b are different, such as Figure 4 As shown, the chip on the left is the first filter 1000a, and the chip on the right is the second filter 1000b. The piezoelectric substrate 10a of the first filter 1000a and the second filter 1000b and piezoelectric substrate 10b are two independent piezoelectric substrates.

[0094] In this embodiment, the difference between the piezoelectric substrate 10a of the first filter 1000a and the piezoelectric substrate 10b of the second filter 1000b can be understood as the piezoelectric substrates 10a and 10b being separate. Their structures and the materials used can be the same or different, and this embodiment does not limit this. Fabricating the two filters on different wafers can meet different frequency combination requirements and facilitates fabrication.

[0095] It should be noted that the first filter 1000a can be a surface acoustic wave filter as described in the previous embodiment. The thickness range of its temperature compensation layer, the thickness range of its IDT electrode, the structure of its IDT electrode, the material of its temperature compensation layer, the thickness and material of its piezoelectric layer, etc., can be referred to the relevant description in the previous embodiment. This application embodiment will not repeat these details.

[0096] Please see Figure 11 and Figure 12 (a) Figure shows the impedance distribution of the first filter in the CA band. (b) Figure shows a comparison of the passband of the second filter in the single-on state and the CA state. The red line represents the passband of the second filter in the single-on state, and the blue line represents the passband of the second filter in the CA state (i.e., when the first and second filters transmit RF signals simultaneously). Figure 11 For comparison, the ratio of the thickness of the temperature compensation layer to the thickness of the IDT electrode is 3.8. Figure 12 In one example, the ratio of the thickness of the temperature compensation layer to the thickness of the IDT electrode is 3.3.

[0097] from Figure 11 It can be seen that in the comparative example, the real part of the impedance corresponding to point m3 is larger, and the amplitude of the corresponding plate wave is larger. Under CA conditions, the passband of the second filter has a significant dip at point m3. From Figure 12As can be seen from the embodiments of this application, the real parts of the impedances corresponding to m1, m2, and m6 are small. Although there are plate waves, the amplitude of the plate waves is small and has little impact on the passband of the second filter in the CA state.

[0098] This application embodiment also provides an elastic wave device, which includes at least two filters: a first filter 1000a and a second filter 1000b. The first filter 1000a includes a piezoelectric substrate 10, at least two IDT electrodes located on one side of the piezoelectric substrate, and a temperature compensation layer covering the at least two IDT electrodes. The passband of the first filter 1000a corresponds to a first frequency band, and the passband of the second filter 1000b corresponds to a second frequency band. Radio frequency signals in the first and second frequency bands can be transmitted simultaneously. The thickness H of the temperature compensation layer of the first filter 1000a is configured to attenuate plate waves outside the passband of the first filter 1000a, the frequency corresponding to which the plate wave is located within the passband of the second filter 1000b.

[0099] In this embodiment, the frequency of the first frequency band can be lower than that of the second frequency band, or it can be higher than that of the second frequency band. That is, the plate wave of the first filter 1000a can be located on the high-frequency side of the passband of the first filter 1000a, or it can be located on the low-frequency side. Preferably, the frequency of the first frequency band is lower than that of the second frequency band, and the plate wave of the first filter 1000a is located on the high-frequency side of the passband of the first filter 1000a.

[0100] In this embodiment, in the first filter 1000a and the second filter 1000b that have carrier aggregation requirements, by adjusting the thickness of the temperature compensation layer of the first filter 1000a, the plate wave of the first filter 1000a located in the passband of the second filter 1000b can be weakened. While meeting the TCF requirements of the first filter, this not only helps to improve the out-of-band suppression level of the first filter 1000a, but also reduces the impact on the passband performance of the second filter 1000b in CA state, thereby improving the CA performance of the elastic wave device.

[0101] In one specific implementation, the center frequency of the passband of the first filter 1000a is f01, the center frequency of the passband of the second filter 1000b is f02, and the ratio of f02 to f01 is in the range of [1.2, 1.6].

[0102] Preferably, the ratio of f02 to f01 is in the range of [1.3, 1.5].

[0103] In another specific embodiment, the thickness of the temperature compensation layer of the first filter 1000a is H, the thickness of the IDT electrode of the first filter 1000a is h, and the ratio of H to h is in the range of (1, 3.5).

[0104] For example, when the main component of the material of the IDT electrode of the first filter 1000a is copper, the ratio of the thickness H of the temperature compensation layer of the first filter 1000a to the thickness h of the IDT electrode 20 is in the range of [2.5, 3.5].

[0105] For example, if the main component of the material of the IDT electrode of the first filter 1000a is another metal, and the ratio of the density of the metal to the density of copper is a, the ratio of the thickness H of the temperature compensation layer of the first filter 1000a to the thickness h of the IDT electrode 20 is in the range of [2.5 / a, 3.5 / a].

[0106] For example, when the main component of the material of the IDT electrode of the first filter 1000a is molybdenum, the ratio of the thickness H of the temperature compensation layer of the first filter 1000a to the thickness h of the IDT electrode is in the range of [2.2, 3.1].

[0107] For example, the relative bandwidth of the first filter 1000a is less than or equal to 7%, and the ratio of H to h is in the range of [2.2, 3.5].

[0108] For example, the relative bandwidth of the first filter 1000a is greater than 7%, and the ratio of H to h is in the range of (1, 2.2).

[0109] It should be noted that the above features and corresponding effects can be referred to the relevant descriptions of the two embodiments above. In addition, other features of the first filter 1000a and the second filter 1000b can also be referred to the relevant descriptions of the two embodiments above. The embodiments of this application will not be repeated here.

[0110] This application also provides a radio frequency (RF) front-end module, which includes an antenna, a switch, an amplifier, and a duplexer (or multiplexer). The antenna is used to receive external signals or transmit RF signals. The switch is located between the antenna and the duplexer (or multiplexer) to control signal transmission between them. When the amplifier is a low-noise amplifier, when the switch is closed, the duplexer (or multiplexer) filters the external signal received by the antenna and outputs a signal with a preset frequency to the low-noise amplifier. When the amplifier is an RF power amplifier, when the switch is closed, the duplexer (or multiplexer) filters the RF signal amplified by the RF power amplifier and outputs an RF signal with a preset frequency to the antenna, which then transmits the RF signal.

[0111] In one embodiment, the duplexer (or multiplexer) may be an elastic wave device as described above, or may include an elastic wave device as described above.

[0112] The radio frequency front-end module provided in this application includes the elastic wave device provided in the aforementioned embodiment. By adjusting the thickness of the temperature compensation layer of the surface acoustic wave filter, the plate wave outside the passband of the surface acoustic wave filter can be weakened, thereby improving the out-of-band suppression level of the surface acoustic wave filter. Furthermore, in CA state, it can also reduce the impact on the passband performance of other filters in the CA band, thereby improving CA performance.

[0113] This application also provides an electronic device, which includes a substrate and a radio frequency (RF) front-end module mounted on the substrate. The substrate and the RF front-end module are electrically connected. The RF front-end module includes the elastic wave device provided in the foregoing embodiments.

[0114] In one embodiment, the substrate is a printed circuit board to enable operational control of the radio frequency (RF) front-end module. The electronic device of this application utilizes the RF front-end module to receive and / or transmit signals.

[0115] For example, electronic devices may be computers, mobile phones, tablets, smartwatches, vehicle terminals, and navigation devices that need to receive and / or transmit radio frequency signals, and this application does not limit them.

[0116] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. An elastic wave device, characterized in that, include: A first filter and a second filter, the first filter comprising a piezoelectric substrate, at least two IDT electrodes located on one side of the piezoelectric substrate, and a temperature compensation layer, the temperature compensation layer covering the at least two IDT electrodes; The passband of the first filter corresponds to the first frequency band, and the passband of the second filter corresponds to the second frequency band. The radio frequency signals of the first frequency band and the radio frequency signals of the second frequency band can be transmitted simultaneously. The center frequency of the passband of the first filter is f01, and the center frequency of the passband of the second filter is f02. The ratio of f02 to f01 is in the range of [1.2, 1.6]. The thickness of the temperature compensation layer of the first filter is H, and the thickness of the IDT electrode of the first filter is h. The ratio of H to h is in the range of (1, 3.5).

2. The elastic wave device according to claim 1, characterized in that, The ratio of f02 to f01 is in the range of [1.3, 1.5].

3. The elastic wave device according to claim 1, characterized in that, The main component of the material of the IDT electrode of the first filter is copper, and the ratio of H to h is in the range of [2.5, 3.5].

4. The elastic wave device according to claim 1, characterized in that, The ratio of the density of the main component of the material of the IDT electrode of the first filter to the density of copper is a, and the ratio of H to h is in the range of [2.5 / a, 3.5 / a].

5. The elastic wave device according to claim 1 or 4, characterized in that, The main component of the material of the IDT electrode of the first filter is molybdenum, and the ratio of H to h is in the range of [2.2, 3.1].

6. The elastic wave device according to claim 1, characterized in that, The relative bandwidth of the first filter is less than or equal to 7%, and the ratio of H to h is in the range of [2.2, 3.5].

7. The elastic wave device according to claim 1, characterized in that, The relative bandwidth of the first filter is greater than 7%, and the ratio of H to h is in the range of (1, 2.2).

8. The elastic wave device according to claim 1, characterized in that, The first frequency band has a frequency range of 1805Hz-1880Hz, and the second frequency band has a frequency range of 2496Hz-2690Hz; or, The first frequency band has a frequency range of 2110Hz-2170Hz, and the second frequency band has a frequency range of 2496Hz-2690Hz; or, The first frequency band has a frequency range of 1990Hz-1920Hz, and the second frequency band has a frequency range of 2496Hz-2690Hz.

9. The elastic wave device according to claim 1, characterized in that, The second filter is a surface acoustic wave (SAW) filter. The first filter and the second filter share the same piezoelectric substrate; alternatively, the piezoelectric substrate of the first filter is different from that of the second filter. The second filter is a bulk acoustic wave filter.

10. The elastic wave device according to claim 1, characterized in that, The thickness H of the temperature compensation layer of the first filter is in the range of [300nm, 1600nm]; and / or, The thickness h of the IDT electrode of the first surface acoustic wave filter is in the range of [0.07λ, 0.1λ].

11. The elastic wave device according to claim 1, characterized in that, The piezoelectric substrate of the first filter includes a piezoelectric layer, wherein the material of the piezoelectric layer is lithium niobate; or, The piezoelectric substrate of the first filter includes a piezoelectric layer and a substrate stacked together, wherein the piezoelectric layer is made of lithium niobate.

12. The elastic wave device according to claim 11, characterized in that, The thickness of the piezoelectric layer is in the range of [100nm, 500nm].

13. An elastic wave device, characterized in that, include: A first filter and a second filter, the first filter comprising a piezoelectric substrate, at least two IDT electrodes located on one side of the piezoelectric substrate, and a temperature compensation layer, the temperature compensation layer covering the at least two IDT electrodes; The passband of the first filter corresponds to the first frequency band, and the passband of the second filter corresponds to the second frequency band. The radio frequency signals of the first frequency band and the radio frequency signals of the second frequency band can be transmitted simultaneously. The thickness H of the temperature compensation layer of the first filter is configured to attenuate the plate wave outside the passband of the first filter, and the frequency point corresponding to the plate wave is located within the passband of the second filter.

14. The elastic wave device according to claim 13, characterized in that, The frequency of the first frequency band is lower than the frequency of the second frequency band.

15. The elastic wave device according to claim 13 or 14, characterized in that, The center frequency of the passband of the first filter is f01, and the center frequency of the passband of the second filter is f02. The ratio of f02 to f01 is in the range of [1.2, 1.6].

16. The elastic wave device according to claim 15, characterized in that, The ratio of f02 to f01 is in the range of [1.3, 1.5].

17. The elastic wave device according to claim 13, characterized in that, The thickness of the IDT electrode of the first filter is h, and the ratio of H to h is in the range of (1, 3.5).

18. The elastic wave device according to claim 17, characterized in that, The main component of the material of the IDT electrode of the first filter is copper, and the ratio of H to h is in the range of [2.5, 3.5].

19. The elastic wave device according to claim 17, characterized in that, The ratio of the density of the main component of the material of the IDT electrode of the first filter to the density of copper is a, and the ratio of H to h is in the range of [2.5 / a, 3.5 / a].

20. The elastic wave device according to claim 17 or 19, characterized in that, The main component of the material of the IDT electrode of the first filter is molybdenum, and the ratio of H to h is in the range of [2.2, 3.1].

21. The elastic wave device according to claim 17, characterized in that, The relative bandwidth of the first filter is less than or equal to 7%, and the ratio of H to h is in the range of [2.2, 3.5].

22. The elastic wave device according to claim 17, characterized in that, The relative bandwidth of the first filter is greater than 7%, and the ratio of H to h is in the range of (1, 2.2).

23. An elastic wave device, characterized in that, include: A surface acoustic wave (SAW) filter, comprising a piezoelectric substrate, at least two independent thermal detachment (IDT) electrodes located on one side of the piezoelectric substrate, and a temperature compensation layer covering the at least two IDT electrodes; The thickness H of the temperature compensation layer is configured to attenuate the plate wave outside the passband of the surface acoustic wave filter, and the frequency point corresponding to the plate wave is located in the range of 1.2 to 1.6 times the resonant frequency fr of the main mode of the surface acoustic wave filter.

24. The elastic wave device according to claim 23, characterized in that, The frequency point corresponding to the plate wave is located in the range of 1.3 to 1.5 times the resonant frequency fr of the main mode of the surface acoustic wave filter.

25. The elastic wave device according to claim 23, characterized in that, The thickness of the IDT electrode is h, and the ratio of H to h is in the range of (1, 3.5).

26. The elastic wave device according to claim 25, characterized in that, The main component of the material of the IDT electrode is copper, and the ratio of H to h is in the range of [2.5, 3.5].

27. The elastic wave device according to claim 25, characterized in that, The ratio of the density of the main component of the material of the IDT electrode of the first filter to the density of copper is a, and the ratio of H to h is in the range of [2.5 / a, 3.5 / a].

28. The elastic wave device according to claim 25 or 27, characterized in that, The main component of the material of the IDT electrode is molybdenum, and the ratio of H to h is in the range of [2.2, 3.1].

29. The elastic wave device according to claim 25, characterized in that, The relative bandwidth of the surface acoustic wave filter is less than or equal to 7%, and the ratio of H to h is in the range of [2.2, 3.5].

30. The elastic wave device according to claim 25, characterized in that, The relative bandwidth of the surface acoustic wave filter is greater than 7%, and the ratio of H to h is in the range of (1, 2.2).

31. A radio frequency front-end module, characterized in that, include: The elastic wave device as described in any one of claims 1-30.

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