Elastic wave device
By setting up a specifically arranged mass-added electrode on the piezoelectric substrate, the problem of low Q value of the elastic wave device in complex environments is solved, and efficient performance improvement is achieved.
Patent Information
- Application Number
- CN202510970912.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-15
- Publication Date
- 2025-10-28
AI Technical Summary
Existing elastic wave devices struggle to achieve stable and efficient high Q values in complex working environments. Existing solutions typically require complex manufacturing processes or additional system compensation mechanisms, increasing costs and potentially introducing new performance limitations.
Mass-added electrodes are added to the non-overlapping areas of the first and second conductive thin film patterns on the piezoelectric substrate to form a specific arrangement of mass-added electrodes, such as those set at the ends or staggered areas of busbars and electrode fingers. Materials include aluminum, copper, platinum, tungsten, gold, silver, molybdenum, tantalum, etc.
The Q value of the elastic wave device was increased while the resonant frequency and anti-resonant frequency remained essentially unchanged, thereby improving the device's performance and stability.
Smart Images
Figure CN120856091A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of radio frequency technology, and more particularly to an elastic wave device. Background Technology
[0002] Elastic wave devices are resonators, filters, or multiplexers based on the propagation characteristics of elastic waves, and are widely used in wireless communication, sensors, and signal processing. In these applications, the performance of elastic wave devices is typically significantly affected by their quality factor (Q value). The Q value is a key parameter measuring the energy loss of an elastic wave device; a high Q value means low energy consumption and high selectivity, thus enabling more efficient signal transmission and higher sensitivity.
[0003] However, in actual design and manufacturing processes, the Q value of elastic wave devices is often limited by various factors, such as material defects, unreasonable structural design, process errors, and environmental interference. These problems can lead to increased energy loss in elastic wave devices, thereby significantly reducing their Q value and affecting overall performance.
[0004] Despite extensive research efforts to improve the Q-value of elastic wave devices, including optimizing material selection (such as using high-velocity, low-loss materials), improving fabrication processes (such as reducing defect density), and designing novel structures (such as multilayer structures or special electrode configurations), achieving stable and efficient high-Q elastic wave devices in complex operating environments remains challenging. Furthermore, existing solutions typically require complex manufacturing processes or additional system compensation mechanisms, which not only increases costs but may also introduce new performance limitations.
[0005] Therefore, developing a new method and structure to effectively improve the Q value of elastic wave devices while taking into account manufacturing costs and practical application needs remains an important research direction. Summary of the Invention
[0006] Based on the above problems, the purpose of this invention is to provide an elastic wave device with a high Q value.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] An elastic wave device includes a piezoelectric substrate, on which a first conductive thin film pattern is disposed. A second conductive thin film pattern is disposed on a first portion of the surface of the first conductive thin film pattern. The second conductive thin film pattern has a different pattern and film thickness from the first conductive thin film pattern. A plurality of mass-added electrodes are disposed on the second portion of the surface of the first conductive thin film pattern. The mass-added electrodes are periodically arranged along the direction of elastic wave propagation and / or in a direction perpendicular to the direction of elastic wave propagation.
[0009] As an alternative, the first conductive thin film pattern includes an interdigital transducer, which includes a first electrode finger, a second electrode finger, a first bus bar, and a second bus bar. A plurality of first electrode fingers and second electrode fingers are arranged alternately and parallel to each other in the direction of elastic wave propagation. The first bus bar and the second bus bar are distributed on both sides of the first electrode fingers and the second electrode fingers. The first end of each first electrode finger is connected to the first bus bar, the first end of each second electrode finger is disconnected from the first bus bar, the second end of each second electrode finger is connected to the second bus bar, and the second end of each first electrode finger is disconnected from the second bus bar.
[0010] As an alternative, the second conductive film pattern is disposed on the first busbar and the second busbar, and the mass-addition electrode is disposed on the first busbar and the second busbar in a region offset from the second conductive film pattern.
[0011] As an alternative, the mass-added electrode is located on the side of the second conductive thin film pattern on the first busbar that is closer to the first electrode finger and on the side of the second conductive thin film pattern on the second busbar that is closer to the second electrode finger.
[0012] As an alternative, a second conductive thin film pattern is disposed on the first busbar and the second busbar, and a mass-added electrode is disposed on the first electrode finger and the second electrode finger.
[0013] As an alternative, the mass-addition electrode is located at the end of the first electrode finger and the end of the second electrode finger.
[0014] As an alternative, the first conductive thin film pattern also includes a reflector located on both sides of the interdigital transducer along the direction of elastic wave propagation. The reflector includes a third electrode finger and a third bus bar. A plurality of third electrode fingers are arranged in parallel at intervals along the direction of elastic wave propagation, and two third bus bars are distributed at both ends of the third electrode fingers, with the end of each third electrode finger connected to the corresponding third bus bar.
[0015] As an alternative, the thickness of the mass-added electrode is less than the thickness of the second conductive thin film pattern.
[0016] As an alternative, the material of the mass-added electrode includes at least one of aluminum, copper, platinum, tungsten, gold, silver, molybdenum, and tantalum.
[0017] As an alternative, the piezoelectric substrate is a piezoelectric block or a multilayer substrate composed of a piezoelectric thin film and a non-piezoelectric substrate.
[0018] The beneficial effects of this invention are:
[0019] This elastic wave device improves its performance by adding a mass-added electrode to the non-overlapping region of the first and second conductive thin film patterns on the piezoelectric substrate. This allows the resonant frequency and anti-resonant frequency of the elastic wave device to remain essentially unchanged compared to the original device, but with a higher Q value. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the elastic wave device provided in the comparative example;
[0021] Figure 2 This is the admittance / Q value-frequency curve of the elastic wave device provided in the comparative example;
[0022] Figure 3 This is a schematic diagram of the elastic wave device provided in Embodiment 1 of the present invention;
[0023] Figure 4 This is a detailed schematic diagram of the mass-added electrode provided in Embodiment 1 of the present invention;
[0024] Figure 5 This is a comparison diagram of the admittance / conductance-frequency curves of the elastic wave device of Embodiment 1 and the elastic wave device of the comparative example of the present invention;
[0025] Figure 6 This is a comparison diagram of the Q-frequency curves of the elastic wave device of Embodiment 1 and the elastic wave device of the comparative example of the present invention;
[0026] Figure 7 This is a comparison diagram of the phase-frequency curves of the elastic wave device of Embodiment 1 and the elastic wave device of the comparative example of the present invention;
[0027] Figure 8 This is a schematic diagram of the elastic wave device provided in Embodiment 2 of the present invention;
[0028] Figure 9 This is a schematic diagram of the elastic wave device provided in Embodiment 3 of the present invention;
[0029] Figure 10 This is a schematic diagram of the elastic wave device provided in Embodiment 4 of the present invention.
[0030] In the attached image:
[0031] 1' Piezoelectric substrate; 2' First conductive thin film pattern; 21' Interdigitated transducer electrode; 22' Reflector electrode; 3' Second conductive thin film pattern;
[0032] 1. Piezoelectric substrate; 2. First conductive thin film pattern; 21. Interdigital transducer; 211. First electrode finger; 212. Second electrode finger; 213. First busbar; 214. Second busbar; 22. Reflector; 221. Third electrode finger; 222. Third busbar; 3. Second conductive thin film pattern; 4. Mass-added electrode. Detailed Implementation
[0033] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.
[0034] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0035] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.
[0036] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.
[0037] Furthermore, the terms "first" and "second" are merely used to distinguish between different terms in description and do not have any special meaning.
[0038] Before proceeding, let's first explain and introduce the relevant technologies of elastic wave devices.
[0039] In recent years, elastic wave devices based on piezoelectric substrates have attracted widespread attention due to their high Q-value performance and have been applied in many fields such as radar, communication, and navigation. Elastic wave devices based on piezoelectric substrates consist of a conductive material thin film pattern formed on a piezoelectric substrate.
[0040] The piezoelectric substrate is either a piezoelectric block or a multilayer substrate composed of a piezoelectric film and a non-piezoelectric substrate. The piezoelectric materials constituting the piezoelectric block or piezoelectric film mainly include lithium niobate, lithium tantalate, gallium nitride, aluminum nitride, or zinc oxide. The piezoelectric block or piezoelectric film is cut to align with the crystal axes of the front and back sides of the piezoelectric block or piezoelectric film, thus allowing for different tangential choices. In the industry, Euler angles are used to define these tangentials. For example, the Euler angles for a 30°Y cut piezoelectric block or piezoelectric film are (0°, 120°, 0°), the Euler angles for a Z cut piezoelectric block or piezoelectric film are (0°, 0°, 0°), the Euler angles for a 128°Y cut piezoelectric block or piezoelectric film are (0°, 38°, 0°), and the Euler angles for a 32°Y45°X cut piezoelectric block or piezoelectric film are (0°, 122°, 45°).
[0041] "Admittance" is a physical quantity describing the response of a circuit element to alternating current and voltage, usually denoted by the symbol Y. For a circuit element, the admittance Y is equal to the combination of conductance G and susceptance B in complex form, i.e., Y = G + jB, where j is the imaginary unit. In this embodiment, the admittance (dB) can be obtained by the formula Y(dB) = 20 × lg|Y|.
[0042] "Transverse mode" refers to the fluctuation between the resonant frequency and the anti-resonant frequency of an elastic wave device (resonator), which is usually caused by diffraction of elastic waves during propagation.
[0043] The quality factor (Q-value) is a physical quantity that measures the degree of energy loss in a system. For elastic wave devices, the Q-value is defined as the ratio of the system's stored energy to the energy lost per unit time.
[0044] Non-piezoelectric substrates are single-layer or multi-layer substrates made of high-velocity acoustic materials, and are therefore also called "high-velocity acoustic components." The speed of sound for bulk waves propagating in high-velocity acoustic components is higher than the speed of sound for elastic waves propagating in piezoelectric layers, thereby increasing the speed of sound of elastic waves in the piezoelectric layer and raising the frequency of the device. Furthermore, high-velocity acoustic components can effectively confine the elastic waves propagating in the piezoelectric layer within the piezoelectric layer to prevent leakage, thereby improving the Q value of the device.
[0045] High-speed components are made of materials with high sound velocities, such as silicon, sapphire, silicon carbide, and aluminum nitride. Table 1 shows the sound velocities of elastic waves in three different modes in various materials.
[0046] Table 1. Sound velocity of three different modes of elastic waves in various materials.
[0047]
[0048] A “conductive thin film pattern” typically includes interdigitated transducer (IDT) electrodes, reflector electrodes, interdigitated transducer busbars, and reflector busbars.
[0049] Comparative example:
[0050] Please see Figure 1 As shown, this comparative example provides an elastic wave device, including a piezoelectric substrate 1'. The piezoelectric substrate 1' is a piezoelectric multilayer substrate formed by a piezoelectric thin film, a low-velocity layer, and a high-velocity substrate, and a first conductive thin film pattern 2' is formed on it. The first conductive thin film pattern 2' includes an interdigital transducer electrode 21' and a reflector electrode 22'.
[0051] The interdigital transducer electrode 21' includes multiple first IDT electrode fingers, multiple second IDT electrode fingers, and first and second IDT busbars arranged parallel to each other and interleaved, perpendicular to the extension direction of the first and second IDT electrode fingers. Reflector electrodes 22' are disposed on both sides of the interdigital transducer electrode 21' along the elastic wave propagation direction.
[0052] A second conductive film pattern 3' is disposed on the first conductive film pattern 2'. The second conductive film pattern 3' overlaps with the first conductive film pattern 2' in the first IDT busbar and the second IDT busbar. The second conductive film pattern 3' has a different pattern and film thickness than the first conductive film pattern 2'.
[0053] Specifically, the piezoelectric thin film is a 30°YX lithium niobate thin film with an Euler angle of (0°, 120°, 0°) at 810 nm; the low-velocity layer is silicon dioxide at 950 nm; the high-velocity substrate is a silicon substrate at 675 μm; the wavelength λ of the elastic wave is 5.11 μm; the first conductive thin film pattern 2' is copper with a thickness of 28 nm and aluminum with a thickness of 311 nm; and the second conductive thin film pattern 3' is aluminum with a thickness of 3 μm.
[0054] Figure 2 The admittance / Q-frequency curve of the comparative example elastic wave device is shown. The curve shows that the elastic wave device has a resonant frequency of 731 MHz and an anti-resonant frequency of 770 MHz, with a maximum Q value of approximately 5200.
[0055] Example 1:
[0056] Please see Figure 3As shown, this embodiment provides an elastic wave device, including a piezoelectric substrate 1. A first conductive thin film pattern 2 is disposed on the piezoelectric substrate 1. A second conductive thin film pattern 3 is disposed on a first part of the surface of the first conductive thin film pattern 2. The second conductive thin film pattern 3 has a different pattern and film thickness than the first conductive thin film pattern 2. A plurality of mass-added electrodes 4 are disposed on the second part of the surface of the first conductive thin film pattern 2. The mass-added electrodes 4 are periodically arranged along the elastic wave propagation direction and in a direction perpendicular to the elastic wave propagation direction.
[0057] The piezoelectric substrate 1 is a multilayer substrate formed by a piezoelectric thin film, a low-velocity layer, and a high-velocity substrate. The first conductive thin film pattern 2 includes an interdigital transducer 21, which includes a first electrode finger 211, a second electrode finger 212, a first bus bar 213, and a second bus bar 214. A plurality of first electrode fingers 211 and second electrode fingers 212 are arranged alternately and parallel to each other in the direction of elastic wave propagation. The first bus bar 213 and the second bus bar 214 are distributed on both sides of the first electrode fingers 211 and the second electrode fingers 212. The first end of each first electrode finger 211 is connected to the first bus bar 213, and the first end of each second electrode finger 212 is connected to the first bus bar 213. The first end is disconnected from the first busbar 213, the second end of each second electrode finger 212 is connected to the second busbar 214, and the second end of each first electrode finger 211 is disconnected from the second busbar 214; the first conductive thin film pattern 2 also includes a reflector 22, which is located on both sides of the interdigital transducer 21 along the direction of elastic wave propagation. The reflector 22 includes a third electrode finger 221 and a third busbar 222. A plurality of third electrode fingers 221 are arranged in parallel at intervals along the direction of elastic wave propagation, and two third busbars 222 are distributed at both ends of the third electrode fingers 221, and the end of each third electrode finger 221 is connected to the corresponding third busbar 222.
[0058] Specifically, the second conductive thin film pattern 3 is disposed on the first busbar 213 and the second busbar 214, and the mass-addition electrode 4 is disposed on the first busbar 213 and the second busbar 214 in a region offset from the second conductive thin film pattern 3.
[0059] Furthermore, the mass-addition electrode 4 is located on the side of the second conductive thin film pattern 3 on the first busbar 213 near the first electrode finger 211 and on the side of the second conductive thin film pattern 3 on the second busbar 214 near the second electrode finger 212.
[0060] In this embodiment, multiple mass-adding electrodes 4 are periodically arranged along the direction of elastic wave propagation on the first busbar 213 and the second busbar 214, and two are periodically arranged in a direction perpendicular to the direction of elastic wave propagation, thereby forming an array structure. See details. Figure 4 .
[0061] Specifically, the piezoelectric thin film is a 30°YX lithium niobate thin film with an Euler angle of (0°, 120°, 0°) at 810 nm; the low-velocity layer is silicon dioxide at 950 nm; the high-velocity substrate is a silicon substrate at 675 μm; the wavelength λ of the elastic wave is 5.11 μm; the first conductive thin film pattern 2 is copper with a thickness of 28 nm and aluminum with a thickness of 311 nm; and the second conductive thin film pattern 3 is aluminum with a thickness of 3 μm.
[0062] In addition, the thickness of the mass-added electrode 4 is less than the thickness of the second conductive thin film pattern 3.
[0063] Optionally, the mass-added electrode 4 is composed of one or more of aluminum, copper, platinum, tungsten, gold, silver, molybdenum, and tantalum.
[0064] Figure 5 A comparison graph of admittance / conductance-frequency curves of the elastic wave device of this embodiment and the elastic wave device of the comparative example is shown. As can be seen from the curves, after adding the array structure of the mass-added electrode 4, the resonant frequency and anti-resonant frequency of the elastic wave device of this embodiment and the elastic wave device of the comparative example remain essentially unchanged.
[0065] Figure 6 A comparison graph of the Q-frequency curves of the elastic wave device of this embodiment and the elastic wave device of the comparative example is shown. As can be seen from the curves, after adding the array structure of the mass-added electrode 4, the Q-value of the elastic wave device of this embodiment is significantly higher than that of the elastic wave device of the comparative example.
[0066] Figure 7 A comparison graph of the phase-frequency curves of the elastic wave device of this embodiment and the elastic wave device of the comparative example is shown. As can be seen from the curves, the phase between the resonant frequency and the anti-resonant frequency of the elastic wave device of this embodiment is closer to -90° than that of the elastic wave device of the comparative example, indirectly reflecting that the elastic wave device of this embodiment has a higher Q value at the resonant frequency.
[0067] Example 2:
[0068] Please see Figure 8 As shown, this embodiment provides an elastic wave device, including a piezoelectric substrate 1. A first conductive thin film pattern 2 is disposed on the piezoelectric substrate 1. A second conductive thin film pattern 3 is disposed on a first part of the surface of the first conductive thin film pattern 2. The second conductive thin film pattern 3 has a different pattern and film thickness than the first conductive thin film pattern 2. A plurality of mass-added electrodes 4 are disposed on the second part of the surface of the first conductive thin film pattern 2. The mass-added electrodes 4 are periodically arranged along the elastic wave propagation direction and in a direction perpendicular to the elastic wave propagation direction.
[0069] Based on Embodiment 1, in the elastic wave device of this embodiment, a mass-added electrode 4 is also provided on the first electrode finger 211 and the second electrode finger 212.
[0070] Specifically, the mass supplement electrode 4 is located at the end of the first electrode finger 211 and the end of the second electrode finger 212. The mass supplement electrode 4 at the end of the first electrode finger 211 and the mass supplement electrode 4 on the second electrode finger 212 near the second busbar 214 are on the same straight line. The mass supplement electrode 4 at the end of the second electrode finger 212 and the mass supplement electrode 4 on the first electrode finger 211 near the first busbar 213 are on the same straight line.
[0071] With this arrangement, the elastic wave device of this embodiment also has a higher Q value than the elastic wave device of the comparative example; at the same time, the elastic wave device also has better transverse mode suppression capability.
[0072] Example 3:
[0073] Please see Figure 9 As shown, this embodiment provides an elastic wave device, including a piezoelectric substrate 1. A first conductive thin film pattern 2 is disposed on the piezoelectric substrate 1. A second conductive thin film pattern 3 is disposed on a first part of the surface of the first conductive thin film pattern 2. The second conductive thin film pattern 3 has a different pattern and film thickness than the first conductive thin film pattern 2. A plurality of mass-added electrodes 4 are disposed on the second part of the surface of the first conductive thin film pattern 2. The mass-added electrodes 4 are periodically arranged along the elastic wave propagation direction and in a direction perpendicular to the elastic wave propagation direction.
[0074] The difference between the elastic wave device in this embodiment and the elastic wave device in Embodiment 1 is that the number of mass-added electrodes 4 arranged periodically along the direction of elastic wave propagation is different. Similarly, the elastic wave device in this embodiment still has a higher Q value than the elastic wave device in the comparative example.
[0075] Example 4:
[0076] Please see Figure 10 As shown, this embodiment provides an elastic wave device, including a piezoelectric substrate 1. A first conductive thin film pattern 2 is disposed on the piezoelectric substrate 1. A second conductive thin film pattern 3 is disposed on a first part of the surface of the first conductive thin film pattern 2. The second conductive thin film pattern 3 has a different pattern and film thickness than the first conductive thin film pattern 2. A plurality of mass-added electrodes 4 are disposed on the second part of the surface of the first conductive thin film pattern 2. The mass-added electrodes 4 are periodically arranged only in a direction perpendicular to the direction of elastic wave propagation. A single mass-added electrode 4 is disposed in a direction perpendicular to the direction of elastic wave propagation.
[0077] The difference between the elastic wave device of this embodiment and the elastic wave device of Embodiment 1 is that the number of mass-added electrodes 4 arranged periodically along the direction perpendicular to the propagation of the elastic wave is different. Similarly, the elastic wave device of this embodiment still has a higher Q value than the elastic wave device of the comparative example.
[0078] Example 5:
[0079] Based on Embodiment 1, Embodiment 2, Embodiment 3 or Embodiment 4, this embodiment provides an elastic wave filter, including a series arm resonator and a parallel arm resonator, wherein at least one of the series arm resonator and the parallel arm resonator includes the above-mentioned elastic wave device, thereby ensuring the stable performance of the elastic wave filter.
[0080] Example 6:
[0081] Based on Embodiment 5, this embodiment provides a multiplexer, including an antenna terminal connected to an antenna and multiple filter devices connected to the antenna terminal, at least one of which includes the aforementioned elastic wave filter, thereby ensuring the stable performance of the multiplexer.
[0082] In summary, the elastic wave devices of the above embodiments improve the performance of the elastic wave device, elastic wave filter, and multiplexer by adding a mass-added electrode 4 to the non-overlapping region of the first conductive thin film pattern 2 and the second conductive thin film pattern 3 on the piezoelectric substrate 1, so that the resonant frequency and anti-resonant frequency of the elastic wave device remain basically unchanged compared with the original device, but have a higher Q value.
[0083] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.
Claims
1. An elastic wave device, characterized in that, The device includes a piezoelectric substrate (1), on which a first conductive thin film pattern (2) is disposed. A second conductive thin film pattern (3) is disposed on a first part of the surface of the first conductive thin film pattern (2). The second conductive thin film pattern (3) has a different pattern and film thickness from the first conductive thin film pattern (2). A plurality of mass-added electrodes (4) are disposed on the second part of the surface of the first conductive thin film pattern (2). The mass-added electrodes (4) are periodically arranged along the direction of elastic wave propagation and / or in a direction perpendicular to the direction of elastic wave propagation.
2. The elastic wave device according to claim 1, characterized in that, The first conductive thin film pattern (2) includes an interdigital transducer (21), which includes a first electrode finger (211), a second electrode finger (212), a first bus bar (213), and a second bus bar (214). A plurality of first electrode fingers (211) and second electrode fingers (212) are arranged alternately and parallel to each other in the direction of elastic wave propagation. The first bus bar (213) and the second bus bar (214) are distributed on both sides of the first electrode fingers (211) and the second electrode fingers (212). The first end of each first electrode finger (211) is connected to the first bus bar (213), the first end of each second electrode finger (212) is disconnected from the first bus bar (213), the second end of each second electrode finger (212) is connected to the second bus bar (214), and the second end of each first electrode finger (211) is disconnected from the second bus bar (214).
3. The elastic wave device according to claim 2, characterized in that, The second conductive thin film pattern (3) is disposed on the first busbar (213) and the second busbar (214), and the mass-added electrode (4) is disposed on the first busbar (213) and the second busbar (214) in a region offset from the second conductive thin film pattern (3).
4. The elastic wave device according to claim 3, characterized in that, The mass-addition electrode (4) is located on the side of the second conductive thin film pattern (3) on the first busbar (213) near the first electrode finger (211) and on the side of the second conductive thin film pattern (3) on the second busbar (214) near the second electrode finger (212).
5. The elastic wave device according to claim 2, characterized in that, The second conductive thin film pattern (3) is disposed on the first busbar (213) and the second busbar (214), and the mass-added electrode (4) is disposed on the first electrode finger (211) and the second electrode finger (212).
6. The elastic wave device according to claim 5, characterized in that, The mass-addition electrode (4) is located at the end of the first electrode finger (211) and the end of the second electrode finger (212).
7. The elastic wave device according to claim 2, characterized in that, The first conductive thin film pattern (2) further includes a reflector (22), which is located on both sides of the interdigital transducer (21) along the elastic wave propagation direction. The reflector (22) includes a third electrode finger (221) and a third bus bar (222). A plurality of the third electrode fingers (221) are arranged in parallel at intervals along the elastic wave propagation direction. Two third bus bars (222) are distributed at both ends of the third electrode fingers (221), and the end of each third electrode finger (221) is connected to the corresponding third bus bar (222).
8. The elastic wave device according to claim 1, characterized in that, The thickness of the mass-added electrode (4) is less than the thickness of the second conductive thin film pattern (3).
9. The elastic wave device according to claim 1, characterized in that, The material of the mass-addition electrode (4) includes at least one of aluminum, copper, platinum, tungsten, gold, silver, molybdenum, and tantalum.
10. The elastic wave device according to claim 1, characterized in that, The piezoelectric substrate (1) is a piezoelectric block or a multilayer substrate composed of a piezoelectric thin film and a non-piezoelectric substrate.