Using gap gratings to reduce the transverse mode of surface acoustic wave electroacoustic devices

Abstract

This disclosure relates to an electroacoustic device comprising a piezoelectric material and an electrode structure. The electrode structure includes a first busbar (622) and a second busbar (624). The electrode structure also includes a first conductive structure (629a) connected to the first busbar and a second conductive structure (629b) connected to the second busbar. The first and second conductive structures are disposed between the first and second busbars. Each of the first and second conductive structures includes a plurality of conductive segments (631) separated from each other and extending toward one of the first or second busbars. The electrode structure also includes electrode fingers (626, 626a, 626b) arranged in an interdigital manner and each connected to the first or second conductive structure. The electrode fingers have a pitch (632) different from the pitch (654) of the plurality of conductive segments.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Patent Application Serial No. 17 / 302,221, filed April 27, 2021, entitled “SURFACE ACOUSTIC WAVE ELECTROACOUSTIC DEVICE USING GAP GRATING FOR REDUCED TRANSVERSAL MODES”, and also claims the benefit of U.S. Provisional Patent Application No. 63 / 017,914, filed April 30, 2020, entitled “SURFACE ACOUSTIC WAVE ELECTROACOUSTIC DEVICE USING GAP GRATING FOR REDUCED TRANSVERSAL MODES”, which has been assigned to its assignee and is expressly incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to surface acoustic wave (SAW) electroacoustic devices such as SAW resonators, and more specifically to interdigital transducer (IDT) electrode structures for electroacoustic devices that reduce transverse acoustic modes. Background Technology

[0004] Electronic devices include traditional computing devices such as desktop computers, laptops, tablets, smartphones, wearable devices (such as smartwatches), and internet servers. These diverse electronic devices provide human users with information, entertainment, social interaction, confidentiality, security, productivity, transportation, manufacturing, and other services. Many of the functions of these various electronic devices rely on wireless communication. Wireless communication systems and devices are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, and broadcasting. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems (e.g., Long Term Evolution (LTE) systems or New Radio (NR) systems).

[0005] Wireless communication transceivers used in these electronic devices typically include multiple radio frequency (RF) filters used to filter signals at specific frequencies or frequency ranges. In many applications, electroacoustic devices (e.g., "acoustic filters") are used to filter high-frequency (e.g., typically greater than 100 MHz) signals. Using piezoelectric materials as the vibrating medium, acoustic resonators operate by converting electrical signal waves propagating along an electrical conductor into sound waves propagating via the piezoelectric material. Sound waves propagate at a speed with an amplitude much smaller than that of electromagnetic waves. Generally, the amplitude of a wave's propagation speed is proportional to the wavelength of the wave. Therefore, after converting an electrical signal into an acoustic signal, the wavelength of the acoustic signal wave is significantly smaller than the wavelength of the electrical signal wave. The smaller wavelength of the resulting acoustic signal allows for the use of smaller filter devices to perform filtering. This allows the use of acoustic resonators in electronic devices with size constraints, such as those listed above (e.g., particularly portable electronic devices such as cellular phones).

[0006] With the increasing number of frequency bands used in wireless communication and the desired bandwidth of filters, the performance of acoustic filters has become increasingly important for reducing losses and improving the overall performance of electronic devices. Therefore, there is a growing demand for acoustic filters with improved performance. Summary of the Invention

[0007] In one aspect of this disclosure, an electroacoustic device is provided. The electroacoustic device includes a piezoelectric material. The electroacoustic device also includes an electrode structure comprising a first busbar and a second busbar. The electrode structure further includes a first conductive structure connected to the first busbar and a second conductive structure connected to the second busbar. The first and second conductive structures are disposed between the first and second busbars. Each of the first and second conductive structures includes a plurality of conductive segments spaced apart from each other and extending toward one of the first or second busbars. The electrode structure also includes electrode fingers arranged in an interdigital manner and each connected to the first or second conductive structure. The electrode fingers have a pitch different from the pitch of the plurality of conductive segments.

[0008] In another aspect of this disclosure, an apparatus including an electrode structure for an electroacoustic device is provided. The electrode structure includes a first conductive structure and a second conductive structure. The electrode structure also includes a third conductive structure connected to the first conductive structure and disposed between the first and second conductive structures. The third conductive structure includes a plurality of first conductive segments separated from each other and extending from the first conductive structure toward the second conductive structure. The electrode structure also includes a plurality of first conductive fingers separated from each other and each connected to the third conductive structure, each of the first plurality of conductive fingers extending from the third conductive structure toward the second conductive structure. The electrode structure also includes a fourth conductive structure connected to the second conductive structure and disposed between the second and first conductive structures. The fourth conductive structure includes a plurality of second conductive segments separated from each other and extending from the second conductive structure toward the first conductive structure. The electrode structure also includes a plurality of second conductive fingers separated from each other and each connected to the fourth conductive structure, each of the second plurality of conductive fingers extending from the fourth conductive structure toward the first conductive structure. The first plurality of conductive fingers intersect with the second plurality of conductive fingers to form a plurality of forked fingers. The pitch of the multiple interdigitated fingers is different from the pitch of the multiple first conductive segments and the pitch of the multiple second conductive segments.

[0009] In another aspect of this disclosure, a method is provided for filtering an electrical signal via an electroacoustic device comprising a piezoelectric material and an interdigital transducer. The method includes providing the electrical signal to terminals of the interdigital transducer. The method further includes reducing transverse acoustic modes via a gap grating structure respectively connected between respective buses of the interdigital transducer and electrode fingers. The pitch of the gap grating structure differs from the pitch of the electrode fingers.

[0010] In another aspect of this disclosure, a method for forming an electroacoustic device is provided. The method includes forming a piezoelectric material layer. The method also includes forming an electrode structure on or over the piezoelectric material. Forming the electrode structure includes forming a first busbar and a second busbar. Forming the electrode structure further includes forming a first conductive structure connected to the first busbar and a second conductive structure connected to the second busbar. The first and second conductive structures are disposed between the first and second busbars. The first and second conductive structures each have a plurality of conductive segments separated from each other and extending toward one of the first or second busbars. Forming the electrode structure further includes forming electrode fingers arranged in an interdigitated manner and each connected to the first or second conductive structure. The electrode fingers are formed to have a pitch different from the pitch of the plurality of conductive segments.

[0011] In another aspect of this disclosure, an electroacoustic device is provided. The electroacoustic device includes a piezoelectric material. The electroacoustic device also includes an electrode structure comprising a first busbar and a second busbar. The electrode structure further includes electrode fingers arranged in an interdigital manner and connected to the first busbar or the second busbar. The electrode structure also includes components for controlling the velocity of sound in a first region and a second region, the first region being between the first busbar and the electrode fingers, and the second region being between the second busbar and the electrode fingers. The components for controlling the velocity of sound include a plurality of conductive components spaced apart from each other, the plurality of conductive components having a pitch different from that of the electrode fingers. Attached Figure Description

[0012] Figure 1A This is a perspective view of an example of an electroacoustic device.

[0013] Figure 1B yes Figure 1A A side view of an electroacoustic device.

[0014] Figure 2A This is a top view of an example of the electrode structure of an electroacoustic device.

[0015] Figure 2B This is a top view of another example of the electrode structure of an electroacoustic device.

[0016] Figure 3A This is a perspective view of another example of an electroacoustic device.

[0017] Figure 3B yes Figure 3A A side view of an electroacoustic device.

[0018] Figure 4 This is a diagram of a portion of the electrode structure of an electroacoustic device, aligned with a plot showing the sound velocity distribution in different regions of the electroacoustic device.

[0019] Figure 5A and Figure 5B This is a diagram illustrating an example of an electrode structure, showing a reference. Figure 4 Examples of different implementations of the defined trap area.

[0020] Figure 6A This is a diagram illustrating an example of the electrode structure of an electroacoustic device for reducing transverse acoustic modes according to certain aspects of this disclosure.

[0021] Figure 6B Based on certain aspects of this disclosure Figure 6A A figure showing an example of one implementation of the electrode structure.

[0022] Figure 6C Based on certain aspects of this disclosure Figure 6AA figure showing an example of another embodiment of the electrode structure.

[0023] Figure 6D Based on certain aspects of this disclosure Figure 6A A figure showing an example of another embodiment of the electrode structure.

[0024] Figure 7 It is shown Figure 6A A graph showing the measurement of acoustic wave propagation angle and frequency in different regions of the electrode structure.

[0025] Figure 8 It shows including Figure 6B A graph showing the admittance and frequency of an electroacoustic device compared to an electroacoustic device with an alternative electrode structure.

[0026] Figure 9A This illustrates certain aspects of the present disclosure for forming materials including piezoelectric materials and Figure 6A A flowchart illustrating an example of a method for constructing an electroacoustic device with an electrode structure.

[0027] Figure 9B This is a flowchart illustrating an example of a method for filtering electrical signals via an electroacoustic device comprising a piezoelectric material and an interdigital transducer, according to certain aspects of this disclosure.

[0028] Figure 10 It can include Figure 6A A schematic diagram of an electroacoustic filter circuit with an electrode structure.

[0029] Figure 11 It can be used in it Figure 10 A functional block diagram of at least a portion of a simplified example of a wireless transceiver circuit with a filter circuit.

[0030] Figure 12 It is an environmental diagram that includes electronic devices, such as wireless transceivers, etc. Figure 11 The transceiver circuit. Detailed Implementation

[0031] The detailed description set forth below with reference to the accompanying drawings is intended as a description of exemplary embodiments and is not intended to represent the only embodiments in which the invention may be practiced. The term "exemplary" as used throughout this specification means "serving as an example, instance, or illustration" and should not necessarily be construed as preferred or advantageous over other exemplary embodiments. The detailed description includes specific details used to provide a thorough understanding of the exemplary embodiments. In some cases, certain devices are shown in block diagram form. Common elements in the following drawings may be identified using the same reference numerals.

[0032] Electroacoustic devices employing electrode structures on the surface of piezoelectric materials (such as surface acoustic wave (SAW) resonators) are being designed to cover a wider frequency range (e.g., 500 MHz to 6 GHz) to achieve higher bandwidth (e.g., up to 25%) and improved efficiency and performance. Typically, some SAW resonators are designed to allow sound waves to propagate through the piezoelectric material in a specific direction (e.g., a dominant acoustic mode). However, due to the properties of the specific piezoelectric material used and the way it is excited by the electrode structure, at least some undesirable acoustic modes may be generated in other directions. For example, transverse acoustic modes can be excited in the piezoelectric material in directions transverse to the dominant (e.g., fundamental) acoustic mode. These transverse acoustic modes may be undesirable and have an adverse effect on filter performance (e.g., introducing ripples in the filter's passband). By adjusting the characteristics of the electrode structure, the sound velocity in individual transverse regions can be controlled in a manner that reduces transverse acoustic modes. The adjusted characteristics may depend on the type of piezoelectric material and other characteristics of the SAW resonator. Aspects of this disclosure relate to specific electrode structure configurations for reducing transverse acoustic modes. Specifically, the electrode structure configuration described herein includes the introduction of multiple conductive segments (sometimes referred to herein as gap grating structures) spaced apart from each other, which connect the busbar of the electrode structure to the electrode fingers. In particular, the gap grating structure has a specific pitch to control the sound velocity according to the propagation direction to reduce transverse modes.

[0033] Figure 1A This is a perspective view of an example of an electroacoustic device 100. The electroacoustic device 100 can be configured as a SAW resonator or as part of a SAW resonator. In some descriptions herein, the electroacoustic device 100 may be referred to as a SAW resonator. However, other types of electroacoustic devices may exist that can be constructed based on the principles described herein. The electroacoustic device 100 includes an electrode structure 104 on the surface of a piezoelectric material 102, which may be referred to as an interdigital transducer (IDT). The electrode structure 104 typically includes a first comb-shaped electrode structure and a second comb-shaped electrode structure (conductive and typically metallic), having electrode fingers extending from two busbars toward each other, the electrode fingers being arranged in an interlocking manner between the two busbars (e.g., in an interdigital arrangement). An electrical signal excited in the electrode structure 104 (e.g., an applied AC voltage) is converted into an acoustic wave 106, which propagates in a specific direction via the piezoelectric material 102. The acoustic wave 106 is converted back into an electrical signal and provided as an output. In many applications, the piezoelectric material 102 has a specific crystal orientation such that when the electrode structure 104 is arranged relative to the crystal orientation of the piezoelectric material 102, the acoustic waves propagate primarily in a direction perpendicular to the direction of the fingers (e.g., parallel to the generatrix).

[0034] Figure 1B yes Figure 1A The electroacoustic device 100 along Figure 1A Side view of cross section 107 shown Figure 1A The electroacoustic device 100 is shown as a simplified layer stack including piezoelectric material 102, wherein electrode structures 104 are disposed on the piezoelectric material 102. Electrode structures 104 are conductive and are typically formed of a metallic material. The piezoelectric material can be formed of a variety of materials, such as quartz, lithium tantalate (LiTaO3), lithium niobate (LiNbO3), doped variants of these materials, or other piezoelectric materials. It should be understood that more complex layer stacks including various material layers may be present within the stack. For example, optionally, a temperature compensation layer 108, indicated by dashed lines, may be disposed above the electrode structures 104. The piezoelectric material 102 may extend, wherein multiple interconnected electrode structures are disposed on the piezoelectric material 102 to form a multi-resonator filter or provide multiple filters. Although not shown, when provided as an integrated circuit component, a cap layer may be disposed above the electrode structures 104. The cap layer is applied such that a cavity is formed between the electrode structures 104 and the lower surface of the cap layer. It may also include electrical vias or bumps that allow components to be electrically connected to connectors on a substrate (e.g., via flip chips or other technologies).

[0035] Figure 2A This is a top view of an example of the electrode structure 204a of the electroacoustic device 100. The electrode structure 204a has an IDT 205, which includes a first busbar 222 (e.g., a first conductive segment or track) and a second busbar 224 (e.g., a second conductive segment or track). The first busbar 222 is electrically connected to a first terminal 220, and the second busbar 224 is spaced apart from the first busbar 222 and connected to a second terminal 230. A plurality of conductive fingers 226 are interdigitatedly connected to either the first busbar 222 or the second busbar 224. The fingers 226 connected to the first busbar 222 extend toward the second busbar 224 but are not connected to the second busbar 224, such that there is a small gap between the ends of these fingers 226 and the second busbar 224. Similarly, the fingers 226 connected to the second busbar 224 extend toward the first busbar 222 but are not connected to the first busbar 222, such that there is a small gap between the ends of these fingers 226 and the first busbar 222.

[0036] Along the direction of the generatrix, there exists an overlapping region including a central region, in which a portion of one finger overlaps with a portion of an adjacent finger, as shown in central region 225. This central region 225, including the overlap, may be referred to as an aperture, track, or active region, in which an electric field is generated between the fingers 226 to allow sound waves to propagate in this region of the piezoelectric material 102. The period of the fingers 226 is referred to as the pitch of the IDT. The pitch can be indicated in various ways. For example, in some aspects, the pitch may correspond to the dimension of the distance between the fingers in the central region 225. For example, this distance may be defined as the distance between the center points of each finger (and when the fingers have a uniform thickness, it can typically be measured between the right (or left) edge of one finger and the right (or left) edge of an adjacent finger). In some aspects, the average distance between adjacent fingers may be used as the pitch. The frequency of the piezoelectric material vibration is the self-resonant (also called the “master resonance”) frequency of the electrode structure 204a. The frequency is determined at least in part by the pitch of the IDT 205 and other characteristics of the electroacoustic device 100.

[0037] An IDT 205 is arranged between two reflectors 228 that reflect sound waves back towards the IDT 205 to convert the sound waves into electrical signals via the IDT 205 in the illustrated configuration and to prevent losses (e.g., to confine and prevent escaped sound waves). Each reflector 228 has a grating structure with two buses and conductive fingers, each conductive finger connected to one of the two buses. The pitch of the reflector can be similar to or the same as the pitch of the IDT 205 to reflect sound waves in the resonant frequency range. However, many configurations are possible.

[0038] When converted back to an electrical signal, the converted electrical signal can be provided as an output (such as one of the first terminal 220 or the second terminal 230), while the other terminal can be used as an input.

[0039] Multiple electrode structures are possible. Figure 2A A single-port configuration can generally be shown. Other two-port configurations are also possible. For example, electrode structure 204a can have an input IDT 205, in which each terminal 220 and 230 serves as an input. In this case, adjacent output IDTs (not shown) positioned between reflectors 228 and adjacent to the input IDT 205 can be provided to convert acoustic waves propagating in the piezoelectric material 102 into electrical signals that will be provided at the output terminals of the output IDTs.

[0040] Figure 2BThis is a top view of another example of the electrode structure 204b of the electroacoustic device 100. In this case, a dual-mode SAW (DMS) electrode structure 204b is shown, which is a structure capable of inducing multiple resonances. The electrode structure 204b includes multiple IDTs and a reflector 228 connected as shown. The electrode structure 204b is provided to illustrate various electrode structures to which the principles described herein can be applied, including... Figure 2A and Figure 2B Electrode structures 204a and 204b.

[0041] It should be understood that although a certain number of fingers 226 are shown, the actual number of fingers, as well as the length and width of the fingers 226 and the busbar, may differ in actual implementations. Such parameters depend on the specific application of the filter and the desired frequency. Furthermore, the SAW filter may include multiple interconnected electrode structures, each including multiple IDTs to achieve the desired passband (e.g., multiple interconnected resonators or IDTs to form the desired filter transfer function).

[0042] Figure 3A This is a perspective view of another example of the electroacoustic device 300. The electroacoustic device 300 (e.g., which can be configured as a SAW resonator or as part of a SAW resonator) is similar to... Figure 1A Electroacoustic device 100, but with a different layer stack. Specifically, electroacoustic device 300 includes a thin piezoelectric material 302 disposed on a substrate 310 (e.g., silicon). In some cases, electroacoustic device 300 may be referred to as a thin-film SAW resonator (TF-SAW). Based on the type of piezoelectric material 302 used (e.g., typically having a higher coupling factor relative to electroacoustic device 100 of FIG. 1) and the controlled thickness of the piezoelectric material 302, specific acoustic wave modes can be excited with… Figure 1A The modes in the electroacoustic device 100 are slightly different. Based on the design (layer thickness and material selection, etc.), and... Figure 1A Compared to the electroacoustic device 100, the electroacoustic device 300 can have a higher Q factor. For example, the piezoelectric material 302 can be lithium tantalate (LiTaO3) or some doped variant. Another example of the piezoelectric material 302 in Figure 3 could be lithium niobate (LiNbO3). Typically, the substrate 310 can be much thicker than the piezoelectric material 302 (e.g., as an example, it may be 50 to 100 times thicker, or more). The substrate 310 may include other layers (or other layers may be included between the substrate 310 and the piezoelectric material 302).

[0043] Figure 3B yes Figure 3A A side view of the electroacoustic device 300, showing an exemplary layer stack (along cross section 307). Figure 3BIn the example shown, substrate 310 may include a sublayer such as (e.g., silicon) substrate sublayer 310-1, which may have higher resistance (e.g., a high resistivity layer relative to other layers). Substrate 310 may also include a trap-rich layer 310-2 (e.g., polycrystalline silicon). Substrate 310 may also include a compensation layer (e.g., silicon dioxide (SiO2) or other dielectric materials) that can provide temperature compensation and other properties. These sublayers may be considered as part of substrate 310 or as separate layers on their own. A relatively thin piezoelectric material 302 is disposed on substrate 310 at a specific thickness to provide a specific acoustic mode (e.g., with...). Figure 1A Compared to the electroacoustic device 100, the thickness of the piezoelectric material 102 in the electroacoustic device 100 may not exceed a significant design parameter of a certain thickness and is similar to... Figure 3A and Figure 3B The piezoelectric material 302 of the electroacoustic device 300 can typically be thicker. The electrode structure 304 is positioned above the piezoelectric material 302. In addition, in some aspects, one or more layers (e.g., such as a thin passivation layer) (not shown) may be present above the electrode structure 304.

[0044] Based on the type, thickness, and overall stack of the piezoelectric material, the coupling to the electrode structure 304, and the sound velocity within the piezoelectric material in different regions of the electrode structure 304, the coupling between different types of electroacoustic devices (such as in...) Figure 1A Electroacoustic device 100 and Figure 3A and Figure 3B The electroacoustic devices (300 and above) can be different.

[0045] about Figure 1A and Figure 3A In the electroacoustic devices 100 and 300, one source of potential loss that is expected to be reduced is stray acoustic wave modes, which may include transverse acoustic wave modes. These transverse acoustic wave modes can introduce undesirable ripples in the passband of the filter. Generally, electroacoustic devices are designed to confine or guide sound waves in a central region 225 (e.g., as shown in the image). Figure 2A The effective area shown is used to avoid radiation into the main body (e.g., in the z-direction perpendicular to the surface) or radiating laterally. The limitation of the acoustic waves may result in the generation of a series of transverse acoustic modes (e.g., typically in the direction toward the generatrix and more parallel to the fingers 226). In particular, the excited acoustic waves propagate perpendicular to the fingers 226, but can also be at certain angles relative to the main propagation direction, corresponding to various transverse acoustic modes. Because transverse acoustic modes cause a sharp, deep drop in the filter passband when the corresponding electroacoustic device track is electrically connected, it is desirable to reduce these transverse acoustic modes.

[0046] Figure 4 This is a diagram of a portion of the electrode structure 404 of the electroacoustic device, which is aligned with a graph showing the sound velocity distribution in different regions of the electroacoustic device. Figure 4 The electrode structure 404 shows a portion of an IDT 405 having a first busbar 422, a second busbar 424, and interdigitated fingers 426, which is similar to the reference design. Figure 2A The IDT described. Since the angular and frequency positions of transverse acoustic modes depend on the directional acoustic velocity, in one respect, the transverse velocity distribution within the acoustic track can be designed to reduce transverse acoustic modes and promote the excitation of the dominant or fundamental mode. In particular, electrode structure 404 (and possibly other layers) can be tuned in different regions of electrode structure 404 to modulate the transverse velocity distribution within the acoustic track, thereby reducing transverse acoustic modes (e.g., to effectively form a transverse acoustic waveguide). In some respects, the velocity of sound can correspond to the velocity of sound of the fundamental mode of the electroacoustic device, although this velocity can be understood more generally in some respects to capture or relate to different modes.

[0047] Figure 4 Different regions of electrode structure 404 are shown, which can be designed or structurally modified to adjust the lateral velocity distribution. (See also: Regarding...) Figure 2A The central region 425 (or effective track region or aperture) is defined at the point where the interdigitates overlap (e.g., in a direction parallel to the generatrix) and is where the main pattern or basic pattern is generally intended and designed to propagate perpendicular to the fingers 426.

[0048] On one hand, a blocking region 429 (e.g., a gap region) is defined outside the central region 425. The blocking region 429 includes the area between the first busbar 422 and the fingers 426a connected to the opposing second busbar 424. More specifically, the blocking region 429 includes a first blocking region 429a and a second blocking region 429b. The first blocking region 429a is defined between the first busbar 422 and the unconnected ends of the first set of fingers 426a connected to the second busbar 424. The second blocking region 429b is defined between the second busbar 424 and the unconnected ends of the second set of fingers 426b connected to the first busbar 422. The blocking region 429 may sometimes correspond to or be referred to as a lateral gap, which is included in the IDT to separate metal structures with different potentials (i.e., to separate individual fingers connected to opposing buses, where the buses have different potentials).

[0049] To adjust the lateral velocity distribution, the number of fingers per wavelength within the blocking region 429 (e.g., one finger instead of two fingers as shown in the central region 425), and the distance or size of the blocking region 429 are selected (and / or by adjusting other characteristics within the blocking region 429) to result in a higher sound wave velocity, particularly higher than that in the central region 425. The graph 440 to the right of the electrode structure 404 shows the relative velocity of each region of the electrode structure 404, where the y-axis represents and is aligned with the direction along which the different regions of the electrode structure 404 extend along the fingers 426. As shown by line 450 (see the dashed section), the sound velocity along the x-axis is higher in the blocking region 429 compared to the sound velocity in the central region 425 (e.g., the effective track). Generally, a relatively higher wave velocity can act as a barrier to sound waves because sound waves may propagate more easily where the velocity is lower. The distance / width of the blocking region 429 (e.g., at least 2-3 wavelengths for some applications) can be wider than the distance / width required to fully separate metal structures with different potentials, providing sufficient blocking and preventing sound waves from coupling into the external region.

[0050] In addition to the blocking region 429, another region, referred to as the trap region 427, is provided at any outer boundary of the central region 425 in which the fingers 426 overlap (e.g., defined at each end). Specifically, the first trap region 427a is positioned near or at a first end (e.g., a boundary) of the central region 425 (e.g., the effective region) and is located between the first blocking region 429a and the central region 425 (e.g., in a region of the fingers 426, this region is near the end of the first set of fingers 426a connected to the second busbar 424, wherein this region is away from the second busbar 424). The second trap region 427b is positioned near or at a second end of the central region 425 (opposite to the first end) and is located between the second blocking region 429b and the central region 425 (e.g., in a region of the fingers, this region is near the end of the second set of fingers 426b connected to the first busbar 422, wherein this region is away from the first busbar 422). The trap region 427 may correspond to the outer edge or outer region of the central region 425. The trap region 427 is provided with structural characteristics different from those in the central region 425 to create a region of the electroacoustic device aligned with the trap region 427, which has a reduced sound wave rate, particularly lower than the sound wave rate in the region defined by the central region 425. Such structural characteristics may include widening the electrode fingers 426 in the trap region 427 or increasing the height of the electrode fingers 426 in the trap region 427, but many implementations are possible. Typically, sound waves may tend to propagate more easily at lower speeds. The trap region 427 with its lower sound wave rate can therefore provide a way to shape the lateral amplitude distribution of the basic sound wave pattern.

[0051] As a result of the design and sizing of the blocking region 429, the trapping region 427, and the central region 425, the amplitude of the fundamental acoustic mode in the lateral direction (e.g., the direction of the finger 426) can conform to a rectangular distribution as shown by line 444 in graph 440. The rectangular distribution caused by different acoustic velocities in different regions corresponds to modes where unwanted lateral modes are suppressed. Line 442 in graph 440 corresponds to the fundamental mode amplitude in the lateral direction when there is no trapping region that could cause unwanted lateral modes. Line 446 in graph 440 corresponds to the fundamental mode amplitude in the lateral direction when the trapping region 427 is not deep enough (e.g., the acoustic waves are not sufficiently slowed down in this region). Despite the improvement, unwanted lateral modes may continue to affect performance. Line 448 in graph 440 corresponds to the fundamental mode amplitude in the lateral direction when the trapping region 427 is too deep. This can also lead to unwanted lateral acoustic modes. By adjusting the characteristics of the blocking region 429 and the trapping region 427, the fundamental mode amplitude in the lateral direction can be adjusted to conform to the rectangular distribution indicated by line 444 and lateral modes can be effectively suppressed. The technique of providing the blocking area 429 and the trapping area 427 in this configuration is sometimes referred to as the piston mode.

[0052] Figure 5A and Figure 5B These are diagrams illustrating examples of electrode structures 504a and 504b, showing reference numerals. Figure 4 Examples of different implementations of the defined trap regions 527-1 and 527-2. The blocking region 529 is indicated but not specifically shown or drawn to scale. Instead, electrode structures 504a and 504b are provided to illustrate trap region 527-1 ( Figure 5A ) and 527-2 Figure 5B ) Implementation methods. For example, in Figure 5A In the electrode structure 504a, the trap region 527-1 is shown as a portion 509 of the electrode structure 504a, and portion 509 of the electrode structure 504a has an increased thickness relative to other portions of the effective region. A side view along cross-section 531 is shown on the right. The increased height may result in a decrease in the speed of sound in the trap region 527-1. In another embodiment, as... Figure 5B As shown in electrode structure 504b, the width of electrode structure 504b within trap region 527-2 is wider than that of the effective region. This greater width can result in a slower sound velocity within trap region 527-2. In some embodiments, trap region 527-2 may have a wider width and increased height (e.g., thickness) than the effective region, such as... Figure 5AAs shown. Therefore, any techniques described herein for trap region 527-2 can be combined. In other embodiments, other materials (e.g., a dielectric material layer) may be positioned in trap region 427. Figure 4 This is done to reduce the velocity of sound in trap region 427 (e.g., due to other types of mass loads). Furthermore, one or more trimming operations can be applied to adjust or have a structural effect in each region, such that the relative velocity of sound in trap region 427 is reduced relative to the central region 425. Other implementations using different techniques may also be employed, such that the structural characteristics in trap region 427 are adjusted and differ from those in the central region 425, resulting in a reduced velocity of sound in trap region 427.

[0053] In some electroacoustic device designs, the blocking region 429 can be a parameter sufficient to be adjusted to create a desired transverse sound velocity distribution to work in conjunction with the trapping region 427 to suppress transverse acoustic modes (e.g., achieving relatively high sound velocities compared to the effective region). However, for some other electroacoustic devices that wish to use different materials, configuring the size of the blocking region 429 may not produce a transverse mode acoustic distribution that results in a sound velocity in the blocking region 429 that is high enough to create the desired transverse velocity distribution. For example, Figure 3A and Figure 3B A thin-film electroacoustic device 300 is shown. In some embodiments, the piezoelectric material 302 in this electroacoustic device 300 may be formed of lithium tantalate (LiTaO3). The sound velocity distribution of lithium tantalate may differ from other systems based on coupling factors (and may be partly attributable to specific layer stacks and lithium tantalate thickness, such as...). Figure 3A and Figure 3B (The thin film type shown). For example, for lithium tantalate-based devices, the velocity difference between the central region 425 and the blocking region 429 may be low, so lateral modes may not be easily confined across the entire stopband width of the electroacoustic device 300. Furthermore, for lithium tantalate-based electroacoustic devices, in the central region 425, the increased frequency may correspond to an angle increasing from the propagation direction of the main sound wave (e.g., sometimes referred to as "convex slowness"). However, for lithium tantalate-based systems, in the blocking region 429, the mode frequency decreases with increasing propagation angle ("concave slowness" in the blocking region 429). Concave slowness may be attractive to sound waves, and stray modes can be formed. Therefore, having concave slowness in the blocking region 429 may lead to the excitation of undesirable modes within the blocking region 429. Therefore, it is desirable to provide a structure that achieves convex slowness in the blocking region 429 to reduce undesirable modes in the blocking region 429 and to provide a desired higher sound velocity within the blocking region 429.

[0054] Some techniques for addressing these issues in such electroacoustic devices may be difficult to achieve for higher metallization rates and greater metal heights (and due to other manufacturing difficulties of such solutions) and may increase ohmic losses. Furthermore, for certain configurations, such as when using the above reference... Figure 3A When describing lithium tantalate-based devices, refer to Figure 4 The described blocking region 429 (e.g., including one stirp for each wavelength) may result in slowing down. The aspects of this disclosure described herein relate to implementations for the blocking region 429 to suppress lateral modes while also being easier to manufacture and design. These techniques can be applied to a wide variety of electroacoustic devices, but may offer particular advantages for thin-film electroacoustic devices using lithium tantalate.

[0055] Figure 6A This is a figure illustrating an example of an electrode structure 604 for an electroacoustic device (e.g., a SAW resonator) that reduces transverse acoustic modes according to various aspects of this disclosure. The electrode structure 604 may be disposed on or above (or arranged relative to) a piezoelectric material 602 such that electroacoustic coupling exists between the piezoelectric material 602 and the electrode structure 604. The electrode structure 604 (which may be in the form of or include an IDT 605) includes a first busbar 622 and a second busbar 624. In some aspects, the first busbar 622 and the second busbar 624 may more generally be referred to as conductive structures. In some aspects, the first busbar 622 and the second busbar 624 extend along a certain direction and are parallel or parallel to each other (although some angular difference between the busbars may be possible).

[0056] Electrode structure 604 includes a first conductive structure 629a connected to a first busbar 622 and a second conductive structure 629b connected to a second busbar 624. The first conductive structure 629a and the second conductive structure 629b are disposed between the first busbar 622 and the second busbar 624. Each of the first conductive structure 629a and the second conductive structure 629b includes a plurality of conductive segments 631, which are spaced apart from each other and extend toward one of the first busbar 622 or the second busbar 624. The conductive segments 631 may correspond to or be referred to as conductive strips. The first conductive structure 629a and the second conductive structure 629b, together with conductive structure 629, may correspond to or be referred to as a gap grating structure (e.g., a grating including conductive segments). Conductive structure 629 has a pitch 654. In some aspects, the pitch 654 may correspond to the periodicity of the conductive segments 631. In one aspect, the pitch may be indicated by the distance between the centers of adjacent conductive segments 631. When the conductive segments 631 generally have the same width, the distance can also be defined by the distance between the left (or right) edges of adjacent conductive segments 631. Furthermore, in some aspects where the conductive segments are not uniformly distributed, the pitch 654 can be indicated by the average distance between the centers of adjacent conductive segments. Other methods of measuring or indicating the pitch 654 are also possible. In some aspects, the conductive structure 629 (e.g., a gap grating structure) can correspond to, as referenced... Figure 4 The described blocking region 429). In some aspects, the plurality of conductive segments 631 extend in a direction orthogonal to the directions of the first busbar 622 and the second busbar 624 (however, other angles are also possible). It should be understood that in some applications, the pitch 654 of the conductive structure 629 of the first conductive structure 629a may be different from the pitch for the second conductive structure 629b.

[0057] The electrode structure 604 also includes electrode fingers 626 arranged in an interdigital manner and connected to the first conductive structure 629a or the second conductive structure 629b. Specifically, the electrode fingers 626 include a first plurality of fingers 626a connected to the second conductive structure 629b and extending toward the first busbar 622. Furthermore, the electrode fingers 626 include a second plurality of fingers 626b connected to the first conductive structure 629a and extending toward the second busbar 624. The electrode fingers 626 have a pitch 652. Similar to the description above with reference to FIG2 2, in some aspects, the pitch 652 may correspond to the periodicity of the electrode fingers 626. In some aspects, the pitch 652 may be indicated by the distance between the centers of adjacent electrode fingers 626. When the electrode fingers 626 generally have the same width, this distance may also be defined by the distance between the left edges (or right edges) of adjacent electrode fingers 626. Furthermore, in some aspects where the conductive fingers are not uniformly distributed, the pitch 652 can be indicated by the average distance between the centers of adjacent electrode fingers 626. Other ways of measuring or indicating the pitch 652 are also possible. In some aspects, the electrode fingers 626 extend in a direction orthogonal to the directions of the first generatrix 622 and the second generatrix 624 (although some other angles are possible).

[0058] As shown in the figure, and similar to the reference. Figure 4 The electrode fingers 626 have a central region 625, which may correspond to or include an effective region (also referred to as a track or aperture). In this region, a first plurality of fingers 626a and a second plurality of fingers 626b overlap in the direction in which the first generatrix 622 and the second generatrix 624 extend. A first trap region 627a and a second trap region 627b, together with the trap region 627, are defined on the boundary of the central region 625 (see also reference). Figure 4 (Description of the described trap region 427). In some aspects, a first trap region 627a may be positioned in a region of the electrode fingers 626, aligned with a portion near or located at the end of the first plurality of fingers 626a, which is close to the first conductive structure 629a (wherein a gap exists between the first conductive structure 629a and the first plurality of fingers 626a). Accordingly, a second trap region 627b may be positioned in a region of the electrode fingers, aligned with a portion near or located at the end of the second plurality of fingers 626b, which is close to the second conductive structure 629b (wherein a gap exists between the second conductive structure 629b and the second plurality of fingers 626b). (Refer to the above...) Figure 4 , Figure 5A and Figure 5BThe structural characteristics of the electroacoustic device differ relative to the central region 625 in the first trap region 427a and the second trap region 627b. For example, the structural characteristics may correspond to a portion of the electrode finger 626 that has an increased width or increased height within the first trap region 627 and the second trap region 627, or as referenced above. Figure 4 , Figure 5A and Figure 5B Any other characteristics described. In particular, this structural characteristic results in a sound velocity in the trap region 627 being lower than that in the central region 625 (and also lower than that in the blocking region including the conductive structure 629). In some respects, the dimension of the trap region 627 in the direction in which the electrode fingers 626 extend can be between half the pitch 652 of the electrode fingers 626 and twice the pitch of the electrode fingers 626 (although the amount can vary based on the application).

[0059] As noted, conductive structure 629 (e.g., gap grating structure) corresponds to the structure described in the reference. Figure 4 The described implementation of the blocking region 429. The conductive structure 629 is configured such that the sound velocity of the electroacoustic device is higher in this region of the conductive structure 629 than in the central region 625. In one aspect, the pitch 654 of the plurality of conductive segments 631 of the conductive structure 629 differs from the pitch 652 of the electrode fingers 626. The size of the pitch 654 at least partially allows for a different sound velocity in the region of the conductive structure 629 compared to the central region 625. Furthermore, the pitch 654 of the plurality of conductive segments 631 can be adjusted to achieve a specific transverse velocity distribution to better suppress transverse acoustic modes (e.g., to achieve near-surface velocity distribution). Figure 4 (The rectangular distribution shown by line 444 of the stack of piezoelectric material 602 and electroacoustic device).

[0060] In one aspect, the conductive structure 629 (e.g., a gap grating structure) may include at least two conductive segments 631 per wavelength (the wavelength corresponding to the operating frequency of the electroacoustic device), but has a pitch 654 that differs from the pitch 652 of the electrode fingers 626. In some aspects, the pitch 654 of the plurality of conductive segments 631 of the conductive structure 629 may vary by a relatively small amount compared to the pitch 652 of the electrode fingers 626. For example, no more than ten percent, although other amounts are possible. In one example, the pitch 654 of the conductive segments 631 may be between 0.8 and 1.1 times the pitch 652 of the electrode fingers 626. An exemplary range of pitch 654 from 0.9 to 0.99 times the pitch 652 of the electrode fingers 626 is applicable to various embodiments. In another aspect, the pitch 654 of the plurality of conductive segments 631 of the conductive structure 629 is smaller than the pitch 652 of the electrode fingers 626. In some respects, the pitch 654 of the plurality of conductive segments 631 of the conductive structure 629 may be at least half (e.g., fifty percent) of the pitch 652 of the electrode fingers 626. The transverse acoustic mode distribution (particularly in regions of the conductive structure 629, e.g., a gap grating structure) can be adjusted by regulating the pitch 654 of the plurality of conductive segments 631 of the conductive structure 629. This allows for tuning of the transverse acoustic mode distribution to further suppress transverse acoustic modes.

[0061] As a result of the conductive structure 629 and the specific pitch 654, the difference in acoustic velocity between the region of the conductive structure 629 and the central region 625 increases. As described above with reference to 4, the difference in transverse acoustic velocity between regions (along with the trap region 627) suppresses transverse acoustic modes. Furthermore, the conductive structure 629 can provide convexity within its region, which may be desirable for reducing acoustic modes excited in that region. Moreover, because constructing the conductive segment 631 with the specific pitch 654 can share similar design and manufacturing principles as constructing the finger 626, it may be somewhat easier in terms of design and manufacturing (not just in having a well-controlled pitch 654) to achieve a very specific transverse acoustic velocity distribution, thereby better suppressing transverse acoustic modes. In particular, for other conductive structures, the minimum structural width may be more difficult to achieve compared to the conductive structure 629 (e.g., a gap grating structure).

[0062] Compared to some other implementations, the size of the conductive structure 629 (e.g., a gap grating structure) extending along the direction of the plurality of conductive segments 631 (e.g., in the same direction as the electrode fingers 626) can also be made smaller (e.g., for another structure or for a case where the size of the blocking region 429 is increased to provide the desired sound velocity). In some aspects, the size can be between 1.25 times and 4 times the wavelength for the operating frequency of the electroacoustic device. Having a smaller blocking region, or in other words, using the conductive structure 629, can allow for savings in chip area. This can be particularly valuable for implementations involving cascaded tracks with multiple blocking regions, and can enable smaller chip sizes.

[0063] In some aspects, the conductive structure 629 may not have any other segments parallel to the first busbar 622 or the second busbar 624 and intersecting the conductive segment 631 (e.g., one or two (or more) strips intersecting and crossing the segment 631 in a certain reflector type arrangement). Instead, in some aspects, as described above, the conductive structure 629 may correspond to the conductive segment 631, all of which extend in a direction different from (e.g., orthogonal to the first busbar 622 and the second busbar 624).

[0064] Figure 6B Based on certain aspects of this disclosure Figure 6A A figure showing an example of one embodiment of the electrode structure 604. Figure 6B Electrode structure 604b illustrates small connection pads 656, which can be included for each finger 626 to provide sufficient electrical connection between the finger 626 and the conductive structure 629. Additionally, in some embodiments, multiple conductive segments 631 of the conductive structure 629 are connected to each other by conductive portions (e.g., in some cases, on the side of the conductive segment 631 away from the corresponding busbar to which the conductive segment 631 is connected). For example, a conductive strip 633 connecting all conductive segments 631 can be included (e.g., disposed on the side of the conductive segment 631 away from the corresponding busbar to which the conductive segment 631 is connected). However, many different embodiments are possible, and various ways are conceived and / or may exist for the connection between the conductive structure 629 and the electrode fingers 626. In some respects, as an example, the distance between the end of the conductive segment 631 of the conductive structure 629 and the beginning of the connection pad 656 (e.g., the width of the strip 633 or other connection) is between one-quarter and one-half of the pitch 652 of the electrode fingers 626. Similar dimensions for the connection pads 656 may also be applied.

[0065] Figure 6CBased on certain aspects of this disclosure Figure 6A A figure showing an example of another embodiment of the electrode structure 604. Figure 6C The electrode structure of 604c is similar to Figure 6B However, an embodiment is shown in which only a portion of the conductive segment 631 of the conductive structure 629 is connected (as opposed to all conductive segments 631 being connected). Figure 6B (Compared). It should be understood that other connections between the conductive segments 631 of the conductive structure 629 are possible, wherein one or more conductive segments of the conductive segments 631 are connected to each other. Furthermore, although in Figure 6C Not shown, but electrode structure 604c can be used for, for example Figure 6B Each finger 626 shown includes a connection pad 656 for connecting the conductive structure 629 to the electrode finger 626.

[0066] Figure 6D Based on certain aspects of this disclosure Figure 6A A figure showing an example of another embodiment of the electrode structure 604. Figure 6D The electrode structure 604d shows an embodiment in which the pitch 654 of the plurality of conductive segments 631 of the conductive structure 629 is greater than the pitch 652 of the electrode fingers 626 (e.g., where the pitch 654 is shown as smaller than). Figure 6A The pitch 652 in the conductive section). As mentioned above, in some aspects, the pitch 654 of the conductive section can be within at least 50% of the pitch 652 of the electrode fingers (but in some cases, it can be larger or smaller as shown in the figure, or as referenced above). Figure 6A (within the scope of the description).

[0067] It should be understood that Figure 6A (as well as Figure 6B , Figure 6C and Figure 6D Some dimensions of the electrode structure 604 may not be drawn to scale. For example, the length of the fingers 626 can be much longer, such that the central region 625 includes most of the dimensions of the IDT 605. Furthermore, the electrode structure 604 can be extended further by additional fingers 626, wherein the pitch 652 of the fingers depends on the desired operating frequency of the electroacoustic device. Additionally, as referenced above... Figure 1A , Figure 1B , Figure 2A and Figure 2B The electrode structure 604 may form part of an IDT 605, which may be one of several IDTs that are separate from and / or interconnected with each other.

[0068] The first busbar 622, the second busbar 624, the conductive structure 629, and the electrode fingers 626 can typically be metallic or made of some other conductive material. In some respects, they can be formed from at least some of the aforementioned materials and can be implemented using a variety of different metal stacks.

[0069] Figure 7 It is shown Figure 6A Figure 700 shows the propagation angle versus frequency measurement for different regions of electrode structure 604. On the y-axis, the indicator k with a value of 0... y Corresponding to the main propagation direction, where the increased k y The value corresponds to an increased propagation angle (e.g., this could correspond to a lateral acoustic mode). The x-direction is the frequency. The curve represented by graph 700 is sometimes referred to as the slowness curve. Line 762 corresponds to the curve for the central region 625, sometimes referred to as the track. Line 766 corresponds to the curves for the busbars 622 and 624. Other lines 764 correspond to curves for various values ​​of the pitch 654 of the conductive segment 631 of the conductive structure 629. Line 764 shows that the slowness curve can be adjusted based on the pitch 654 of the conductive structure 629 to correspond to a convex slowness, which is desirable for suppressing acoustic modes that may be generated in the blocking region. Furthermore, as the pitch 654 of the conductive segment 631 (relative to the pitch 652 of the electrode fingers 626) decreases, the rate difference between the central region 625 and the region of the conductive structure 629 increases. It is also shown how the slowness in a region of the conductive structure 629 can be adjusted by varying the pitch 654 of the conductive segment 631. As shown in line 768 for at least a specific pitch 654 of the conductive structure 629, the slowness can be shifted to a concave position. Thus, by adjusting and selecting the pitch 654, the curve can be shifted to a higher frequency (e.g., a higher rate) to the point where the velocity of sound in the blockage is highest but still convex.

[0070] Figure 8 It shows including Figure 6B The electroacoustic device admittance versus frequency curves of the electrode structure 604b compared to the alternative electrode structure are shown in Figure 800. Line 868 corresponds to the use of... Figure 6B The admittance value versus frequency of the electroacoustic device with electrode structure 604b is shown. Line 866 corresponds to the admittance value versus frequency of an electroacoustic device that does not achieve a piston mode (e.g., without conductive structure 629 and trap region 627). As shown, line 866 includes multiple significant ripples caused by performance-degrading transverse acoustic modes. Figure 6B The electrode structure 604b, corresponding to line 868, exhibits significantly less ripple, as shown in the figure, indicating effective suppression of transverse acoustic modes. A similar admittance profile will be applied to the reference... Figure 6A , Figure 6B , Figure 6C and Figure 6D Any electrode structure described.

[0071] Example Operation

[0072] Figure 9A This illustrates certain aspects of the present disclosure for forming a piezoelectric material 602 (Figure 6) and Figure 6A A flowchart illustrating an example of a method 900 for an electroacoustic device with electrode structure 604 is provided. Method 900 is described in the form of a set of boxes specifying operations that can be performed. However, the operations are not necessarily limited to... Figure 9A The order shown or described herein is not fixed, as operations can be performed in an alternative order or in a fully or partially overlapping manner. Furthermore, more, fewer, and / or different operations can be performed to execute method 900 or alternative methods. At block 902, method 900 includes forming a piezoelectric material layer 602. At block 904, method 900 further includes forming an electrode structure 604 on or over the piezoelectric material 602. The electrode structure 604 forming block 904 includes: at block 906, forming a first busbar 622 and a second busbar 624. The electrode structure forming block 904 further includes: at block 908, forming a first conductive structure 629a connected to the first busbar 622 and a second conductive structure 629b connected to the second busbar 624. The first conductive structure 629a and the second conductive structure 629b are formed to be disposed between the first busbar 622 and the second busbar 624. A plurality of conductive segments 631 are formed, each of the first conductive structure 629a and the second conductive structure 629b being freely separated from each other and extending toward one of the first busbar 622 or the second busbar 624. The electrode structure forming frame 904 further includes, at frame 910, electrode fingers 626 formed, the electrode fingers 626 being arranged in an interdigitated manner and connected to the first conductive structure 629a or the second conductive structure 629b. The electrode fingers 626 have a pitch 652 different from the pitch 654 of the plurality of conductive segments 631.

[0073] As described above, the electrode finger 626 has a central region 625, and the first trap region 627a and the second trap region 627b are respectively located on the boundary of the central region 625. In some aspects, at block 912, method 900 may further include adjusting or forming structural characteristics of the electroacoustic device in the first trap region 627 and the second trap region 627 to reduce the speed of sound.

[0074] In some respects, reference Figure 6A This provides a method for filtering electrical signals via an electroacoustic device comprising a piezoelectric material 602 and an interdigital transducer 605. Figure 9BThis is a flowchart illustrating an example of a method 950 for filtering an electrical signal via an electroacoustic device comprising a piezoelectric material 602 and an interdigital transducer 605, according to certain aspects of this disclosure. Method 950 includes, at block 952, providing an electrical signal to the terminals of the interdigital transducer 605. Method 950 also includes, at block 954, reducing transverse acoustic modes via a gap grating structure (e.g., conductive structure 629) respectively connected between respective buses of the interdigital transducer (e.g., a first bus 622 or a second bus 624) and electrode fingers 626, the pitch 654 of the gap grating structure differing from the pitch 652 of the electrode fingers 626.

[0075] have Figure 6A Electroacoustic devices with electrode structure 604 can be used in a variety of applications.

[0076] Figure 10 It can include Figure 6A A schematic diagram of an electroacoustic filter circuit 1000 with electrode structure 604 is provided. The filter circuit 1000 provides an example of the use of electrode structure 604. The filter circuit 1000 includes an input terminal 1002 and an output terminal 1014. A ladder network of SAW resonators is provided between the input terminal 1002 and the output terminal 1014. The filter circuit 1000 includes a first SAW resonator 1004, a second SAW resonator 1006, and a third SAW resonator 1008, all electrically connected in series between the input terminal 1002 and the output terminal 1014. A fourth SAW resonator 1010 (e.g., a shunt resonator) has a first terminal connected between the first SAW resonator 1004 and the second SAW resonator 1006, and a second terminal connected to ground potential. A fifth SAW resonator 1012 (e.g., a parallel resonator) has a first terminal connected between the second SAW resonator 1006 and the third SAW resonator 1008, and a second terminal connected to ground potential. The electroacoustic filter circuit 1000 can, for example, be a bandpass circuit with a passband having a selected frequency range (e.g., on the order of 100 MHz to 3.5 GHz). Figure 10 An example of a ladder network is shown, as described above. Figure 6A The electrode structure 604 can be incorporated into other resonator configurations, such as DMS designs.

[0077] Figure 11 It can include Figure 6A The electrode structure of 604 Figure 10The following is a functional block diagram of at least a portion of a simplified example of a wireless transceiver circuit 1100, representing a filter circuit 1000. The transceiver circuit 1100 is configured to receive a signal / information (shown as I and Q values) for transmission provided to one or more baseband filters 1112. The filtered output is provided to one or more mixers 1114. The output from the one or more mixers 1114 is provided to a driver amplifier 1116, and the output of the driver amplifier 1116 is provided to a power amplifier 1118 to generate an amplified signal for transmission. The amplified signal is output to an antenna 1122 via one or more filters 1120 (e.g., a duplexer, if used as a frequency division duplex transceiver or other filter). The one or more filters 1120 may include... Figure 10 The filter circuit 1000, and may include Figure 6A The electrode structure 604. Antenna 1122 can be used to wirelessly transmit and receive data. Transceiver circuitry 1100 includes a receive path through one or more filters 1120 to provide data to a low-noise amplifier (LNA) 1124 and another filter 1126, then down-converts the received frequency to a baseband frequency through one or more mixer circuits 1128, and then the signal is further processed (e.g., provided to an analog-to-digital converter, then demodulated in the digital domain or otherwise processed). Separate filters may be present for the receive circuitry (e.g., it may have a separate antenna or a separate receive filter), which can be used... Figure 10 The transceiver circuit 1000 is used to implement this. Furthermore, the transceiver circuit 1100 shown represents a simplified example of a transceiver architecture, and other architectures with different filter configurations (e.g., shared or non-shared antennas) are possible.

[0078] Figure 12 This is a diagram of an environment 1200 including electronic device 1202, which includes wireless transceiver 1296, such as... Figure 11 The transceiver circuit 1100 (and may include the use of Figure 6A (The filter of electrode structure 604). In environment 1200, electronic device 1202 communicates with base station 1204 via wireless link 1206. As shown, electronic device 1202 is depicted as a smartphone. However, electronic device 1202 can be implemented as any suitable computing or other electronic device, such as cellular base station, broadband router, access point, cellular or mobile phone, gaming device, navigation device, media device, laptop computer, desktop computer, tablet computer, server computer, network attached storage (NAS) device, smart home appliance, vehicle communication system, Internet of Things (IoT) device, sensor or security device, asset tracker, etc.

[0079] Base station 1204 communicates with electronic device 1202 via wireless link 1206, which can be implemented as any suitable type of wireless link. Although described as a base station tower of a cellular radio network, base station 1204 can be represented or implemented as another device, such as a satellite, terrestrial broadcast tower, access point, peer-to-peer device, mesh network node, fiber optic line, or another electronic device as generally described above. Therefore, electronic device 1202 can communicate with base station 1204 or another device via a wired connection, a wireless connection, or a combination thereof. Wireless link 1206 can include a downlink for transmitting data or control information from base station 1204 to electronic device 1202, and an uplink for transmitting other data or control information from electronic device 1202 to base station 1204. Wireless link 1206 can be implemented using any suitable communication protocol or standard, such as 3GPP LTE, 3GPP NR 5G, IEEE 802.11, IEEE 802.16, Bluetooth, etc. TM wait.

[0080] Electronic device 1202 includes processor 1280 and memory 1282. Memory 1282 may be or form part of a computer-readable storage medium. Processor 1280 may include any type of processor, such as an application processor or a multi-core processor, configured to execute processor-executable instructions (e.g., code) stored in memory 1282. Memory 1282 may include any suitable type of data storage medium, such as volatile memory (e.g., random access memory (RAM)), non-volatile memory (e.g., flash memory), optical media, magnetic media (e.g., magnetic disk or magnetic tape), etc. In the context of this disclosure, memory 1282 is implemented to store instructions 1284, data 1286, and other information of electronic device 1202, and therefore, when configured as a computer-readable storage medium or part thereof, memory 1282 does not include transient propagation signals or carrier waves.

[0081] Electronic device 1202 may also include input / output port 1290 (I / O port 116). I / O port 1290 enables data exchange or interaction with other devices, networks, users, or device components.

[0082] Electronic device 1202 may also include a signal processor (SP) 1292 (e.g., such as a digital signal processor (DSP)). The signal processor 1292 may function similarly to a processor and may be able to execute instructions and / or process information in conjunction with memory 1282.

[0083] For communication purposes, electronic device 1202 also includes a modem 1294, a wireless transceiver 1296, and an antenna (not shown). The wireless transceiver 1296 provides connectivity to a given network and other connected electronic devices using radio frequency (RF) wireless signals, and may include... Figure 11 The transceiver circuit 1100. The wireless transceiver 1296 can facilitate communication over any suitable type of wireless network, such as wireless local area network (LAN) (WLAN), peer-to-peer (P2P) network, mesh network, cellular network, wireless wide area network (WWAN), navigation network (e.g., North American Global Positioning System (GPS) or another Global Navigation Satellite System (GNSS)) and / or wireless personal area network (WPAN).

[0084] Examples of implementation methods are described in the following numbered clauses:

[0085] 1. An electroacoustic device, comprising:

[0086] piezoelectric materials; and

[0087] Electrode structure, including:

[0088] First busbar and second busbar;

[0089] A first conductive structure and a second conductive structure, the first conductive structure being connected to a first busbar and the second conductive structure being connected to a second busbar, the first and second conductive structures being disposed between the first and second busbars, each of the first and second conductive structures comprising a plurality of conductive segments, the plurality of conductive segments being separated from each other and extending toward one of the first or second busbars; and

[0090] Electrode fingers are arranged in an interdigitated manner and each is connected to a first conductive structure or a second conductive structure. The electrode fingers have a pitch different from that of the multiple conductive segments.

[0091] 2. An electroacoustic device according to Clause 1, wherein the pitch of a plurality of conductive segments is smaller than the pitch of the electrode fingers.

[0092] 3. An electroacoustic device according to Clause 1, wherein the pitch of a plurality of conductive segments is within 10 percent of the pitch of the electrode fingers.

[0093] 4. An electroacoustic device according to Clause 1, wherein the pitch of a plurality of conductive segments is greater than fifty percent of the pitch of the electrode fingers.

[0094] 5. An electroacoustic device according to any one of clauses 1 to 4, wherein the electrode fingers have a central region, and a first trap region and a second trap region are respectively positioned on the boundary of the central region, wherein the structural characteristics of the electroacoustic device are different relative to the central region in the first trap region and the second trap region.

[0095] 6. An electroacoustic device according to Clause 5, wherein structural characteristics correspond to a portion of each electrode finger in the electrode fingers, and the portion has at least one of an increased width or an increased height relative to the central region in the first trap region and the second trap region.

[0096] 7. An electroacoustic device according to Clause 5, wherein the structural characteristics correspond to at least one of the following: dielectric material above the trap region, a mass load within the trap region, or the structural effect of a trimming operation.

[0097] 8. An electroacoustic device according to any one of clauses 5 to 7, wherein the sound velocity in the region of the electroacoustic device defined by the first conductive structure and the second conductive structure is higher than that in the region of the electroacoustic device defined by the first trap region, the second trap region and the central region.

[0098] 9. An electroacoustic device according to Clause 8, wherein the speed of sound in the first trap region and the second trap region is lower than the speed of sound in the central region.

[0099] 10. An electroacoustic device according to Clause 5, wherein the size of the trap region in the direction in which the electrode fingers extend is between half the pitch of the electrode fingers and twice the pitch of the electrode fingers.

[0100] 11. An electroacoustic device according to any one of clauses 1 to 4, wherein the electrode fingers have a central region, and a first trap region and a second trap region are respectively positioned on the boundary of the central region, wherein the sound velocity in the region of the electroacoustic device defined by the first trap region and the second trap region is lower than that in the region of the electroacoustic device defined by the central region.

[0101] 12. An electroacoustic device according to any one of clauses 1 to 11, wherein the dimension of the first conductive structure in the direction in which the plurality of conductive segments extend is between 1.25 times and 4 times the wavelength of the operating frequency of the electroacoustic device.

[0102] 13. An electroacoustic device according to any one of clauses 1 to 12, wherein a plurality of conductive segments extend in a direction orthogonal to the directions of the first busbar and the second busbar.

[0103] 14. An electroacoustic device according to any one of clauses 1 to 13, wherein one or more of a plurality of conductive segments are connected to each other by conductive portions.

[0104] 15. The electroacoustic device according to Clause 14, wherein the conductive portion connecting one or more of the plurality of conductive segments is a conductive strip, the conductive strip being connected to at least a portion of the plurality of conductive segments on one side of the plurality of conductive segments, away from one of the respective first busbars or second busbars to which the plurality of conductive segments are connected.

[0105] 16. An electroacoustic device according to any one of clauses 1 to 15, wherein electrode fingers extend in a direction perpendicular to the direction of the first busbar and the second busbar.

[0106] 17. An electroacoustic device according to any one of clauses 1 to 16, wherein the piezoelectric material includes lithium tantalate (LiTaO3).

[0107] 18. An electroacoustic device according to any one of clauses 1 to 17 further includes:

[0108] substrate;

[0109] A trap-rich layer is formed as part of the substrate or disposed on the substrate; and

[0110] A dielectric material layer is disposed on the substrate, and a piezoelectric material is disposed on the dielectric material layer.

[0111] 19. An electroacoustic device according to any one of clauses 1 to 17 further includes:

[0112] Substrate; and

[0113] A compensation layer is disposed on the substrate, and a piezoelectric material is disposed between the electrode structure and the compensation layer.

[0114] 20. An electroacoustic device according to any one of clauses 1 to 19, wherein the electroacoustic device is at least a portion of a SAW resonator, the SAW resonator forming part of a filter circuit.

[0115] 21. An electroacoustic device according to Clause 20, wherein the SAW resonator is part of at least one of a ladder network or a dual-mode SAW circuit.

[0116] 22. An electroacoustic device pursuant to Clause 20, wherein the filter circuitry is part of a transceiver.

[0117] 23. A wireless communication device comprising an electroacoustic device according to Clause 1.

[0118] 24. An apparatus comprising an electrode structure for an electroacoustic device, the electrode structure comprising:

[0119] First conductive structure;

[0120] Second conductive structure;

[0121] A third conductive structure is connected to the first conductive structure and disposed between the first conductive structure and the second conductive structure. The third conductive structure includes a plurality of first conductive segments that are separated from each other and extend from the first conductive structure toward the second conductive structure.

[0122] The first plurality of conductive fingers are separated from each other and each is connected to a third conductive structure, and each of the first plurality of conductive fingers extends from the third conductive structure toward the second conductive structure;

[0123] A fourth conductive structure is connected to the second conductive structure and disposed between the second conductive structure and the first conductive structure. The fourth conductive structure includes a plurality of second conductive segments that are separated from each other and extend from the second conductive structure toward the first conductive structure.

[0124] The second plurality of conductive fingers are separated from each other and each is connected to the fourth conductive structure. Each of the second plurality of conductive fingers extends from the fourth conductive structure toward the first conductive structure. The first plurality of conductive fingers intersect with the second plurality of conductive fingers to form a plurality of forked fingers. The pitch of the plurality of forked fingers is different from the pitch of the plurality of first conductive segments and the pitch of the plurality of second conductive segments.

[0125] 25. The device according to Clause 24, wherein a central region of a plurality of interdigitated fingers is defined at each end by an outer region, wherein the plurality of interdigitated fingers have at least one of an increased thickness or an increased width relative to the central region in the outer region.

[0126] 26. The device according to Clause 24, wherein the central region of the plurality of interdigitated fingers is defined at each end by an outer region, in which the structural characteristics of the device are different relative to the central region.

[0127] 27. The device according to Clause 24, wherein the central region of a plurality of interdigitated fingers is defined at each end by an outer region having a slower sound velocity compared to the central region.

[0128] 28. An apparatus according to any one of clauses 24 to 27, wherein the pitch of the plurality of first conductive segments and the pitch of the plurality of second conductive segments are less than the pitch of the plurality of interdigitated fingers.

[0129] 29. An apparatus according to any one of clauses 24 to 27, wherein the pitch of the plurality of first conductive segments and the pitch of the plurality of second conductive segments are within ten percent of the pitch of the plurality of interdigitated fingers.

[0130] 30. An apparatus according to any one of clauses 24 to 27, wherein the pitch of the plurality of first conductive segments and the pitch of the plurality of second conductive segments are greater than fifty percent of the pitch of the plurality of interdigitated fingers.

[0131] 31. A method for filtering an electrical signal via an electroacoustic device, comprising a piezoelectric material and an interdigital transducer, the method comprising:

[0132] Provide electrical signals to the terminals of the interdigital transducer; and

[0133] Transverse acoustic modes are reduced by means of a gap grating structure. The gap grating structure is connected between the corresponding busbar of the interdigital transducer and the electrode fingers respectively. The pitch of the gap grating structure is different from the pitch of the electrode fingers.

[0134] 32. A method for forming an electroacoustic device, comprising:

[0135] Forming a piezoelectric material layer; and

[0136] An electrode structure is formed on or above a piezoelectric material, wherein the formation of the electrode structure includes:

[0137] Forming the first busbar and the second busbar;

[0138] A first conductive structure connected to a first busbar and a second conductive structure connected to a second busbar are formed, the first and second conductive structures being disposed between the first and second busbars, and multiple conductive segments are formed that are freely separated from each other and extend toward one of the first or second busbars; and

[0139] Electrode fingers are formed, which are arranged in an interdigitated manner and each is connected to a first conductive structure or a second conductive structure. The electrode fingers are formed to have a pitch different from that of the multiple conductive segments.

[0140] 33. The method according to Clause 32, wherein the electrode fingers have a central region and a first trap region and a second trap region located on the boundary of the central region, wherein the method further includes adjusting or forming structural characteristics of the electroacoustic device in the first trap region and the second trap region to reduce the speed of sound.

[0141] 34. An electroacoustic device, comprising:

[0142] piezoelectric materials; and

[0143] Electrode structure, including:

[0144] First busbar and second busbar;

[0145] Electrode fingers, arranged in an interdigitated manner and connected to the first busbar or the second busbar; and

[0146] Components for controlling the speed of sound in a first region and a second region, the first region being between a first busbar and an electrode finger, and the second region being between a second busbar and an electrode finger, the components for controlling the speed of sound comprising a plurality of conductive components spaced apart from each other, the plurality of conductive components having a pitch different from that of the electrode finger.

[0147] The various operations described above can be performed by any suitable component capable of performing the corresponding function. This component may include various hardware components and / or software components and / or modules, including but not limited to circuits, application-specific integrated circuits (ASICs), or processors.

[0148] As an example, the elements, or any portion thereof, or any combination thereof described herein, may be implemented as a “processing system” including one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, system-on-a-chip (SoCs), baseband processors, field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described herein. One or more processors in a processing system may execute software. Software should be interpreted broadly as instructions, instruction sets, code, code segments, program code, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referring to software, firmware, middleware, microcode, hardware description languages, or others.

[0149] Therefore, in one or more example embodiments, the described functional or circuit system blocks can be implemented in hardware, software, or any combination thereof. If implemented in software, these functions can be stored on a computer-readable medium or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media. Storage media can be any available medium that is accessible to a computer. By way of example and not limitation, such computer-readable media can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of computer-readable media of the types described above, or any other medium that can be used to store computer-executable code in the form of computer-accessible instructions or data structures. In some aspects, the components described by the circuit system can be implemented in hardware, software, or any combination thereof.

[0150] Typically, in the case of operations as shown in the figure, these operations can have corresponding devices plus functional components with similar numbers.

[0151] As used herein, the term "determine" encompasses a variety of actions. For example, "determine" can include calculating, computation, processing, derivation, investigation, searching (e.g., looking in a table, database, or other data structure), confirmation, etc. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), etc. Additionally, "determine" can include resolving, selecting, recommending, establishing, etc.

[0152] As used in this article, the phrase “at least one of” in a list of items refers to any combination of these items, including a single member. For example, “at least one of a, b, or c” is intended to cover: a, b, c, ab, ac, bc, and abc, as well as any combination having multiple of the same elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbbc, cc, and ccc, or any other order of a, b, and c).

[0153] The methods disclosed herein include one or more steps or actions for implementing the methods. The method steps and / or actions may be interchanged with each other without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of particular steps and / or actions may be modified without departing from the scope of the claims.

[0154] It should be understood that the claims are not limited to the precise configuration and components described above. Various modifications, alterations, and variations may be made to the arrangement, operation, and details of the above-described methods and apparatus without departing from the scope of the claims.

Claims

1. An electroacoustic device, comprising: piezoelectric materials; as well as Electrode structure, including: First busbar and second busbar; A first conductive structure and a second conductive structure, the first conductive structure being connected to a first busbar, and the second conductive structure being connected to a second busbar, the first conductive structure and the second conductive structure being disposed between the first busbar and the second busbar, each of the first conductive structure and the second conductive structure comprising a plurality of conductive segments, the plurality of conductive segments being separated from each other and extending toward one of the first busbar or the second busbar; and Electrode fingers are arranged in an interdigitated manner and each is connected to the first conductive structure or the second conductive structure, the electrode fingers having a pitch different from the pitch of the plurality of conductive segments of the first conductive structure and the second conductive structure; The dimension of the first conductive structure in the direction in which the plurality of conductive segments extend is between 1.25 times and 4 times the wavelength of the operating frequency of the electroacoustic device.

2. The electroacoustic device according to claim 1, wherein the pitch of the plurality of conductive segments of the first conductive structure and the second conductive structure is smaller than the pitch of the electrode fingers.

3. The electroacoustic device according to claim 1, wherein the pitch of the plurality of conductive segments of the first conductive structure and the second conductive structure is within 10 percent of the pitch of the electrode fingers.

4. The electroacoustic device according to claim 1, wherein the pitch of the plurality of conductive segments of the first conductive structure and the second conductive structure is greater than 50 percent of the pitch of the electrode fingers.

5. The electroacoustic device according to claim 1, wherein the electrode fingers have a central region containing a trap region, the trap region comprising a first trap region and a second trap region respectively located on the boundary of the central region, wherein the structural characteristics of the electroacoustic device are different relative to the central region in the first trap region and the second trap region.

6. The electroacoustic device of claim 5, wherein the structural characteristics correspond to a portion of each of the electrode fingers, and the portion in the first trap region and the second trap region has at least one of an increased width or an increased height relative to the central region.

7. The electroacoustic device of claim 5, wherein the structural characteristic corresponds to at least one of the following: dielectric material located above the trap region, mass load within the trap region, or structural effect of a trimming operation.

8. The electroacoustic device of claim 5, wherein the sound velocity in the region of the electroacoustic device defined by the first conductive structure and the second conductive structure is higher than that in the region of the electroacoustic device defined by the first trap region, the second trap region and the central region.

9. The electroacoustic device according to claim 8, wherein the sound speed in the first trap region and the second trap region is lower than the sound speed in the central region.

10. The electroacoustic device of claim 5, wherein the dimension of the first trap region in the direction in which the electrode fingers extend is between half the pitch of the electrode fingers and twice the pitch of the electrode fingers.

11. The electroacoustic device of claim 1, wherein the electrode fingers have a central region, the central region having a first trap region and a second trap region respectively positioning the boundary of the central region, wherein the sound velocity in the region of the electroacoustic device defined by the first trap region and the second trap region is lower than in the region of the electroacoustic device defined by the central region.

12. The electroacoustic device according to claim 1, wherein the plurality of conductive segments of the first conductive structure and the second conductive structure extend in a direction orthogonal to the directions of the first busbar and the second busbar.

13. The electroacoustic device of claim 1, wherein one or more conductive segments of the plurality of conductive segments of the first conductive structure and the second conductive structure are connected to each other through conductive portions.

14. The electroacoustic device of claim 13, wherein the conductive portion of one or more of the plurality of conductive segments connecting the first conductive structure and the second conductive structure is a conductive strip, the conductive strip being connected to at least a portion of the plurality of conductive segments on one side of a corresponding first busbar or second busbar to which the plurality of conductive segments are connected, away from the first conductive structure and the second conductive structure.

15. The electroacoustic device of claim 1, wherein the electrode fingers extend in a direction orthogonal to the directions of the first busbar and the second busbar.

16. The electroacoustic device according to claim 1, wherein the piezoelectric material comprises lithium tantalate (LiTaO3).

17. The electroacoustic device according to claim 1, further comprising: substrate; A trap-rich layer is formed as part of the substrate or disposed on the substrate; as well as A dielectric material layer is disposed on the substrate, and the piezoelectric material is disposed on the dielectric material layer.

18. The electroacoustic device according to claim 1, further comprising: substrate; as well as A compensation layer is disposed on the substrate, and the piezoelectric material is disposed between the electrode structure and the compensation layer.

19. The electroacoustic device of claim 1, wherein the electroacoustic device is at least a portion of a SAW resonator, the SAW resonator forming part of a filter circuit.

20. The electroacoustic device of claim 19, wherein the filter circuit is part of a transceiver.

21. A method for forming an electroacoustic device, comprising: Forming a piezoelectric material layer; as well as An electrode structure is formed on or above the piezoelectric material, wherein forming the electrode structure includes: Forming the first busbar and the second busbar; A first conductive structure connected to the first busbar and a second conductive structure connected to the second busbar are formed. The first conductive structure and the second conductive structure are disposed between the first busbar and the second busbar. Each of the first conductive structure and the second conductive structure is formed by a plurality of conductive segments, which are separated from each other and extend toward one of the first busbar or the second busbar; and Electrode fingers are formed, the electrode fingers are arranged in an interdigitated manner and each is connected to the first conductive structure or the second conductive structure, and the electrode fingers are formed to have a pitch different from the pitch of the plurality of conductive segments of the first conductive structure and the second conductive structure. The dimension of the first conductive structure in the direction in which the plurality of conductive segments extend is between 1.25 times and 4 times the wavelength of the operating frequency of the electroacoustic device.

22. The method of claim 21, wherein the electrode fingers have a central region and a first trap region and a second trap region located on the boundary of the central region, wherein the method further comprises adjusting or forming structural characteristics of the electroacoustic device in the first trap region and the second trap region to reduce the speed of sound.

23. An electroacoustic device, comprising: piezoelectric materials; as well as Electrode structure, including: First busbar and second busbar; A first conductive structure and a second conductive structure, the first conductive structure being connected to a first busbar, and the second conductive structure being connected to a second busbar, the first conductive structure and the second conductive structure being disposed between the first busbar and the second busbar, each of the first conductive structure and the second conductive structure comprising a plurality of conductive segments, the plurality of conductive segments being separated from each other and extending toward one of the first busbar or the second busbar; and Electrode fingers are arranged in an interdigitated manner and each is connected to the first conductive structure or the second conductive structure. The electrode fingers have a pitch different from the pitch of the plurality of conductive segments. The electrode fingers have a central region and the central region has a first trap region located on the boundary of the central region. The size of the first trap region in the direction in which the electrode fingers extend is between half the pitch of the electrode fingers and twice the pitch of the electrode fingers.

24. The electroacoustic device according to claim 23, wherein... The pitch of the plurality of conductive segments of the first conductive structure and the second conductive structure is greater than 50 percent of the pitch of the electrode fingers.

25. The electroacoustic device according to claim 23, wherein... The electrode finger has a central region containing a trap region, the trap region including a first trap region and a second trap region respectively located on the boundary of the central region, wherein the structural characteristics of the electroacoustic device are different relative to the central region in the first trap region and the second trap region.

26. The electroacoustic device according to claim 25, wherein... The structural characteristics correspond to a portion of each of the electrode fingers, wherein the portion in the first trap region and the second trap region has at least one of an increased width or an increased height relative to the central region.

27. The electroacoustic device according to claim 25, wherein... The structural characteristic corresponds to at least one of the following: dielectric material located above the trap region, mass load within the trap region, or structural effect of a trimming operation.

28. The electroacoustic device according to claim 25, wherein... The sound velocity in the region of the electroacoustic device defined by the first conductive structure and the second conductive structure is higher than in the region of the electroacoustic device defined by the first trap region, the second trap region and the central region.

29. The electroacoustic device according to claim 28, wherein... The speed of sound in the first trap region and the second trap region is lower than the speed of sound in the central region.

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