Cascaded surface acoustic wave device with apodized interdigital transducer

Abstract

Certain aspects of the present disclosure provide an electro-acoustic device and methods for signal processing via the same. An example electro-acoustic device generally includes a first surface acoustic wave (SAW) resonator including a first apodized interdigital transducer (IDT) disposed between a first bus and a second bus, and a second SAW resonator including a second apodized IDT disposed between the second bus and a third bus, where the second bus is angled with respect to at least one of the first bus or the third bus.

Description

Technical Field

[0001] Certain aspects of this invention relate generally to electronic components, and more specifically, to surface acoustic wave (SAW) devices. Background Technology

[0002] Electronic devices include traditional computing devices such as desktop computers, laptops, tablets, smartphones, wearable devices (such as smartwatches), internet servers, and so on. These diverse electronic devices provide human users with information, entertainment, social interaction, security, insurance, productivity, transportation, manufacturing, and other services. Many of the functions of these diverse 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, broadcasting, etc. These systems are able to 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).

[0003] Wireless transceivers used in these electronic devices typically include multiple radio frequency (RF) filters for filtering signals at specific frequencies or frequency ranges. Electroacoustic devices (e.g., "acoustic filters") are used in many applications to filter high-frequency (e.g., typically greater than 100 MHz) signals. Using piezoelectric materials as the vibrating medium, acoustic resonators work by converting electrical signal waves propagating along an electrical conductor into sound waves propagating via the piezoelectric material. Sound waves propagate at an amplitude with a propagation speed significantly smaller than that of electromagnetic waves. Generally, the amplitude of the wave propagation speed is proportional to the wavelength of the wave. Therefore, after the electrical signal is converted into an acoustic signal, the wavelength of the acoustic signal wave is significantly smaller than the wavelength of the electrical signal wave. The resulting smaller wavelength acoustic signal allows filtering to be performed using smaller filter devices. This allows acoustic resonators to be used in electronic devices with size constraints, such as those listed above (e.g., particularly portable electronic devices such as cellular phones).

[0004] Currently, surface acoustic wave (SAW) or bulk acoustic wave (BAW) components are used in wireless communication devices, such as for implementing RF filters. In SAW technology, acoustic waves propagate laterally across the surface of a piezoelectric substrate, accompanied by piezoelectric motion generated by interdigital transducers (IDTs) on the surface. The wavelength of the acoustic wave can be defined by the spacing of the IDTs (e.g., the width of the metal fingers and the gap). In BAW technology, acoustic waves propagate vertically through a three-dimensional structure, with an electric field applied through electrodes above and below the piezoelectric material. In this case, the wavelength is defined by the thickness of the piezoelectric material.

[0005] In one type of SAW device, surface acoustic waves are generated by the input IDT and detected by the output IDT. In another type of SAW device, acoustic energy can be confined using reflectors on either side of the IDT. A planar resonant cavity created between two mirrors composed of reflective metal strips can also be used to capture acoustic energy.

[0006] With the increasing number of frequency bands used in wireless communication and the widening of required filter bandwidth, the performance of acoustic filters is becoming increasingly important for reducing losses and improving the overall performance of electronic devices. Therefore, it is necessary to improve the performance of acoustic filters, especially to reduce intermodulation distortion. Summary of the Invention

[0007] The systems, methods, and devices of the present invention each have several aspects, none of which alone is responsible for their desired properties. Without limiting the scope of this disclosure as set forth by the appended claims, some features will now be briefly discussed. After considering this discussion, and especially after reading the section entitled "Detailed Description," it will be understood how the features of the invention provide advantages including implementations of surface acoustic wave (SAW) technology.

[0008] Some aspects of the present invention provide an electroacoustic device. The electroacoustic device typically includes: a first SAW resonator including a first apodized interdigital transducer (IDT) disposed between a first bus and a second bus; and a second SAW resonator including a second apodized IDT disposed between the second bus and a third bus, wherein the second bus is angled relative to at least one of the first bus or the third bus.

[0009] Certain aspects of the present invention provide an electroacoustic device. The electroacoustic device typically includes: a first SAW resonator including a first IDT disposed between a first bus and a second bus; and a second SAW resonator including a second IDT disposed between the second bus and a third bus, wherein the second bus is angled relative to at least one of the first bus or the third bus, wherein the first IDT includes a first set of fingers extending from the second bus, and wherein the length of the first set of fingers decreases as each of the first set of fingers moves closer to one side of the first IDT.

[0010] Some aspects of the present invention provide a method for signal processing. The method generally includes receiving a signal at a first bus and processing the signal via a first SAW resonator and a second SAW resonator. In some aspects, the first SAW resonator includes a first apodization IDT disposed between the first and second buses, and the second SAW resonator includes a second apodization IDT disposed between the second and third buses, wherein the second bus is angled relative to at least one of the first or third buses. The method may further include providing the processed signal at the third bus.

[0011] Some aspects of the present invention provide a method for signal processing. The method generally includes receiving a signal at a first bus and processing the signal via a first SAW resonator and a second SAW resonator. In some aspects, the first SAW resonator includes a first IDT disposed between the first and second buses, and the second SAW resonator includes a second IDT disposed between the second and third buses, wherein the second bus is angled relative to at least one of the first or third buses, wherein the first IDT includes a first set of fingers extending from the second bus, and wherein the length of the first set of fingers decreases as each finger in the first set of fingers approaches one side of the first IDT. The method may further include providing the processed signal at the third bus.

[0012] To achieve the foregoing and related objectives, one or more aspects include the features fully described below and particularly indicated in the claims. The following description and drawings set forth certain illustrative features of one or more aspects in detail. However, these features indicate only a few of the various ways in which the principles of each aspect can be employed. Attached Figure Description

[0013] To gain a more detailed understanding of the foregoing features of this disclosure, reference can be made to several aspects, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only certain aspects of the invention and should not be construed as limiting its scope, as other equivalent aspects are permissible in the description.

[0014] Figure 1A This is a perspective view of an example electroacoustic device in which certain aspects of this disclosure can be practiced.

[0015] Figure 1B yes Figure 1A A side view of an example electroacoustic device.

[0016] Figure 2A This is a top view of an example electrode structure for an electroacoustic device, in which certain aspects of this disclosure can be practiced.

[0017] Figure 2BThis is a top view of another example electrode structure for an electroacoustic device, in which some aspects of this disclosure can be practiced.

[0018] Figure 3A This is a perspective view of an example electroacoustic device in which certain aspects of this disclosure can be practiced.

[0019] Figure 3B This is a side view of an example electroacoustic device in which certain aspects of this disclosure can be practiced.

[0020] Figure 4A The illustration shows an electroacoustic device with a cascaded surface acoustic wave (SAW) resonator implemented using an IDT, according to certain aspects of this disclosure.

[0021] Figure 4B The illustration shows an implementation of an alternative orientation according to certain aspects of this disclosure. Figure 4A Electroacoustic devices.

[0022] Figure 5 The illustration shows an electroacoustic device with four cascaded SAW resonators according to certain aspects of this disclosure.

[0023] Figure 6 and 7 The diagram illustrates a schematic diagram and implementation of an electroacoustic filter circuit according to certain aspects of this disclosure.

[0024] Figure 8 This is a flowchart depicting an example operation for signal processing according to certain aspects of this disclosure.

[0025] Figure 9 This is another flowchart depicting example operations for signal processing according to certain aspects of this disclosure.

[0026] Figure 10 This is a functional block diagram of at least a portion of an exemplary simplified wireless transceiver circuit, in which an electroacoustic filter circuit may be employed.

[0027] Figure 11 It includes having, for example Figure 10 A diagram of the environment of an electronic device with a wireless transceiver circuit.

[0028] For ease of understanding, the same reference numerals are used where possible to indicate the same elements common to the figures. It is conceivable that elements disclosed in one aspect may be advantageously used in other aspects without specific description. Detailed Implementation

[0029] Certain aspects of this disclosure generally relate to electroacoustic devices having cascaded surface acoustic wave (SAW) devices, with at least two adjacent SAW devices each having an apodized interdigital transducer (IDT). The apodized IDT facilitates suppression of lateral modes in the electroacoustic device. The IDT of each SAW device can be between two buses, and adjacent SAW devices can share a common bus, allowing the SAW devices to be cascaded. In some aspects, the shared bus can be implemented at an angle relative to another bus of an adjacent SAW device, allowing for cascaded SAW devices to be implemented with reduced area consumption compared to other implementations of cascaded SAW devices with apodized IDTs.

[0030] The detailed description set forth below with reference to the accompanying drawings is intended as a description of exemplary implementations and not as representing the only implementation in which the invention can be practiced. The term "exemplary" as used throughout the specification means "serving as an example, instance, or illustration" and should not be construed as a preferred or superior embodiment of other exemplary implementations. The detailed description includes specific details used to provide a thorough understanding of the exemplary implementations. In some instances, some components are shown in block diagram form. The same reference numerals may be used in the following drawings to identify common drawing elements in the drawings.

[0031] Example electroacoustic devices

[0032] Figure 1A This is a perspective view of an example electroacoustic device 100. Electroacoustic device 100 can be configured as a SAW resonator or as part of a SAW resonator. In some descriptions herein, 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.

[0033] Electroacoustic device 100 includes an electrode structure 104 on the surface of piezoelectric material 102, which may be referred to as an interdigital transducer (IDT). Electrode structure 104 typically includes a first comb-shaped electrode structure and a second comb-shaped electrode structure (conductive and typically metallic), wherein electrode fingers extend from two generatrices toward each other and are arranged in an interlocking manner between the two generatrices (e.g., arranged in a crisscrossing manner). An electrical signal excited in electrode structure 104 (e.g., an applied AC voltage) is converted into an acoustic wave 106 propagating through piezoelectric material 102 in a specific direction. The acoustic wave 106 is converted back into an electrical signal and provided as an output. In many applications, piezoelectric material 102 has a specific crystal orientation such that when electrode structure 104 is arranged relative to the crystal orientation of piezoelectric material 102, the acoustic wave propagates primarily in a direction perpendicular to the fingers (e.g., parallel to the generatrices).

[0034] Figure 1B yes Figure 1A Electroacoustic devices 100 along Figure 1AThe diagram shows a side view of section 108. The electroacoustic device 100 is illustrated by a simplified layer stack including piezoelectric material 102, with electrode structures 104 disposed on the piezoelectric material 102. Electrode structures 104 are conductive and typically formed of a metallic material. Alternatively, electrode structures 104 may be formed of a conductive but non-metallic material (e.g., graphene). The piezoelectric material 102 may be formed of a variety of materials, such as quartz, lithium tantalate (LiTaO3), lithium niobate (LiNbO3), doped variants of these materials, other piezoelectric materials, or other crystals. It should be understood that more complex layer stacks including various material layers may exist within the stack. For example, optionally, a temperature compensation layer 110, indicated by dashed lines, may be disposed on the electrode structures 104. The piezoelectric material 102 may extend to have multiple interconnected electrode structures disposed thereon to form a multi-resonant filter or provide multiple filters. Although not shown, a capping layer may be provided on the electrode structures 104 when supplied as an integrated circuit component. A capping layer is applied to form a cavity between the electrode structure 104 and the lower surface of the capping layer. Electrical vias or bumps may also be included, allowing components to be electrically connected to connections on the substrate (e.g., via flip chip or other techniques).

[0035] Figure 2A This is a top view of an example electrode structure 204a for an electroacoustic device. Electrode structure 204a has an IDT 205, which includes a first busbar 222 (e.g., a first conductive segment or rail) electrically connected to a first terminal 220 and a second busbar 224 (e.g., a second conductive segment or rail) spaced apart from the first busbar 222 and connected to a second terminal 230. A plurality of conductive fingers 226 are connected to the first busbar 222 or the second busbar 224 in a crisscross manner. 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 a small gap exists 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 a small gap exists between the ends of these fingers 226 and the first busbar 222. Similarly, small gaps can also be formed between the finger 226 and any structure (e.g., short fingers) extending from the first busbar 222 or the second busbar 224.

[0036] Between the busbars, there exists an overlapping region including a central region, where a portion of one finger overlaps with a portion of a neighboring finger, as shown in central region 225. This overlapping central region 225 may be referred to as an aperture, track, or active region, where an electric field is generated between the fingers 226 to allow sound waves to propagate in this region of the piezoelectric material 102. The periodicity of the fingers 226 is called the pitch of the IDT. Pitch can be indicated in various ways. For example, in some aspects, the pitch may correspond to the magnitude of the distance between the fingers in 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 width, it is typically measured between the right (or left) edge of one finger and the right (or left) edge of a neighboring finger). In some aspects, the average distance between neighboring fingers can be used for the pitch. The frequency of the piezoelectric material's vibration is the principal resonant frequency of the electrode structure 204a. This 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 positioned between two reflectors 228 that reflect sound waves back to the IDT 205. This serves to convert the sound waves into electrical signals via the IDT 205 in the illustrated configuration and to prevent losses (e.g., limiting and preventing escaped sound waves). Each reflector 228 has a grid structure with two buses and conductive fingers, each conductive finger connected to both buses. The pitch of the reflectors can be similar to or the same as the pitch of the IDT 205 to reflect sound waves within a 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 to one of terminals, such as 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 be generally illustrated. Other configurations (e.g., dual-port configurations) are also possible. For example, electrode structure 204a can have an input IDT 205, with each terminal 220 and 230 serving as an input. In this case, a neighboring output IDT (not shown) located between reflectors 228 and adjacent to the input IDT 205 can be provided to convert the acoustic waves propagating in the piezoelectric material 102 into an electrical signal to be provided by the output IDT at the output end.

[0040] Figure 2BThis is a top view of another example electrode structure 204b for an electroacoustic device. In this case, a dual-mode SAW (DMS) electrode structure 204b is illustrated; a DMS structure is a structure that can induce multiple resonances. Electrode structure 204b includes multiple IDTs arranged between reflectors 228 and connected as shown. Electrode structure 204b is provided to illustrate that the principles described herein can be applied to, including... Figure 2A and 2B Various electrode structures of electrode structures 204a and 204b.

[0041] It should be understood that although a certain number of fingers 226 are illustrated, the actual number of fingers, as well as the lengths and widths of the fingers 226 and the busbars, may differ in actual implementations. These parameters depend on the specific application and desired filter characteristics. Furthermore, a SAW filter may include multiple interconnected electrode structures, each comprising multiple IDTs to achieve a desired passband (e.g., multiple interconnected resonators or IDTs to form the desired filter transfer function).

[0042] Electroacoustic devices such as SAW resonators are designed to cover a wider frequency range (e.g., 500 MHz to 6 GHz), have higher bandwidth (e.g., up to 20%), and offer improved efficiency and performance. Typically, SAW resonators are affected by nonlinearity, which causes intermodulation distortion (IMD). For example, slight conductivity of the air or dielectric between the IDT electrodes can cause arcing and potentially degrade the device's nonlinearity, power endurance, and compression. Cascaded acoustic tracks can reduce some amount of intermodulation distortion, but this technique requires increased space and larger SAW devices to implement.

[0043] It is worth noting that the relative permittivity (ε) of the piezoelectric substrate r The influence of substrate dielectric constant on the nonlinearity of SAW filters was investigated using a nonlinear Mason equivalent circuit model. Furthermore, the relative dielectric constant of the material separating the electrodes forming the IDT on the SAW device also affects the nonlinear characteristics of the device. By adjusting the relative dielectric constant of certain dielectric structures in the SAW device, the intermodulation distortion of the device can be reduced.

[0044] Figure 3A This is a perspective view of another example of an 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 1AElectroacoustic 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 than electroacoustic device 100 of FIG. 1) and the controlled thickness of piezoelectric material 302, the specific acoustic wave modes excited can be... Figure 1A The acoustic wave mode in the electroacoustic device 100 is slightly different. Based on the design (layer thickness and material selection, etc.), it differs from... Figure 1A Compared to the electroacoustic device 100, the electroacoustic device 300 may have a higher quality factor (Q). Typically, the substrate 310 may 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).

[0045] Figure 3B yes Figure 3A A side view of the electroacoustic device 300 shows an exemplary layer stack (along cross section 307). Figure 3B In the example shown, substrate 310 may include sublayers such as substrate sublayer 310-1 (e.g., silicon) that may have higher resistance (e.g., high resistivity layers relative to other layers). Substrate 310 may also include trap-rich layer 310-2 (e.g., polycrystalline silicon). Substrate 310 may also include compensation layer 310-3 (e.g., silicon dioxide (SiO2) or another dielectric material) 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 of a specific thickness is provided on substrate 310 to provide specific acoustic modes (e.g., with...). Figure 1A Compared to the electroacoustic device 100, the thickness of the piezoelectric material 102 may not be a critical design parameter exceeding a specific thickness, and with Figure 3A and 3B The piezoelectric material 302 of the electroacoustic device 300 can typically be thicker. The electrode structure 304 is located above the piezoelectric material 302. Additionally, in some aspects, one or more layers (not shown) may be present above the electrode structure 304 (e.g., such as a thin passivation layer).

[0046] Based on the type, thickness, and overall layer stacking of the piezoelectric material, different types of electroacoustic devices, for example, Figure 1A Electroacoustic devices 100 and Figure 3A and 3BThe coupling between the electroacoustic devices 300 to the electrode structure 304 and the sound velocity within the piezoelectric material in different regions of the electrode structure 304 can be different.

[0047] Example resonator with cascaded apodization interdigital transducers (IDTs)

[0048] Lateral modes are a common problem with surface acoustic wave (SAW) resonators. Energy can leak laterally in the SAW tracks (e.g., the transducer fingers of an interdigital transducer (IDT), causing ripples and spikes within the passband of filters implemented using SAW resonators. How strongly these lateral modes are excited depends on various configurations of the SAW resonator, such as crystal cut and layer configuration.

[0049] Various techniques exist for suppressing lateral modes, including apodization or piston designs in IDTs. Apodization techniques may lead to increased area consumption of the SAW resonator because the resonator aperture may increase. In piston designs, regions with different sound velocities are created at the ends of the SAW fingers to constructively confine lateral modes within the SAW track. Using a piston design to suppress lateral modes may require additional processes.

[0050] SAW tracks can be cascaded to meet power and nonlinearity specifications. For example, cascaded resonators are used in various filter implementations to handle high-power signals. If linear apodization is applied to SAW tracks with cascaded SAW resonators, the track size can be doubled in some cases. Other apodization methods (cosine shapes, etc.) are slightly smaller than linear apodization methods, but still result in a significant increase in resonator size.

[0051] Some aspects of this disclosure relate to cascaded SAW resonators implemented using apodized IDTs, while reducing the area consumption of the SAW resonators compared to other implementations of apodized IDTs. To effectively suppress lateral modes using apodization, the length of the fingers across the SAW tracks can be varied, as described in more detail herein. Some aspects achieve apodization of the IDT for cascaded SAW resonators by tilting the connecting bus (i.e., the common bus) between the two SAW resonators.

[0052] The apodization techniques described herein allow the characteristics of cascaded resonators, such as size and static capacitance, to remain largely unchanged while suppressing lateral modes. Furthermore, the dimensions of electroacoustic devices incorporating cascaded SAW resonators can be independent of the apodization ratio. The apodization ratio typically refers to the ratio of the length of the shortest finger of the apodized IDT to the aperture of the apodized IDT. For example, a 30% apodization ratio means that the shortest finger of the IDT is 30% of the aperture size of the IDT. The SAW resonators of the electroacoustic devices disclosed herein can be implemented with various suitable apodization ratios, such as 30% or 100%. In other words, for certain SAW resonator designs, a lower apodization ratio can be used because fewer lateral modes can be exhibited in the design.

[0053] Certain aspects also offer advantages regarding bus modes. Depending on the aperture size and crystal structure, resonant modes also occur between the buses of the SAW orbitals, which can be suppressed by shaping the buses across the orbitals. Certain aspects of this disclosure also suppress resonant modes caused by the tilting of the intermediate buses of the cascaded SAW devices, resulting in SAW resonators of this disclosure having little or no ineffective regions within the IDT, unlike other implementations of apodized SAW resonators.

[0054] Figure 4A An electroacoustic device 400 with a cascaded SAW resonator implemented using an IDT is illustrated according to certain aspects of this disclosure. As shown, the electroacoustic device 400 includes a SAW resonator 430 that can be implemented using a reflector 402, an IDT 420, and a reflector 412. The electroacoustic device 400 may also include a SAW resonator 432 that can be implemented using a reflector 404, an IDT 422, and a reflector 414.

[0055] SAW resonators 430 and 432 can be cascaded. For example, IDT 420 can have bus 406 and bus 410, and IDT 422 can include bus 410 and bus 408. In other words, IDT 420 can include fingers extending from bus 406 that intersect with fingers extending from bus 410, and IDT 422 can include fingers extending from bus 408 that intersect with fingers extending from bus 410. Therefore, in this cascaded resonator configuration, SAW resonators 430 and 432 share a common bus (i.e., bus 410).

[0056] In some respects, busbar 410 may be at an angle relative to busbar 406 or busbar 408 (e.g., in...). Figure 4A (The inclination angle is marked as "tilt angle"). Depending on the apodization ratio to be achieved for IDT 420 and 422, the tilt angle of bus 410 can be greater than 0 degrees and less than or equal to 45 degrees.

[0057] Implementing a busbar 410 with a tilt angle facilitates the implementation of IDTs 420 and 422 as apodized IDTs. For example, IDT 420 includes fingers (e.g., fingers 470, 472) extending from busbar 410, wherein the length of the fingers decreases as each finger approaches the side 462 of IDT 420. As shown, IDT 420 also includes fingers (e.g., fingers 490, 492) extending from busbar 406. As shown, the fingers extending from busbar 406 intersect with the fingers extending from busbar 410. The length of the fingers extending from busbar 406 decreases as each finger approaches the side 462 of IDT 420.

[0058] Similarly, IDT 422 includes fingers (e.g., fingers 480, 482) extending from busbar 410, wherein the length of the fingers increases as each of the finger groups moves closer to side 458 of IDT 422. IDT 422 also includes fingers (e.g., fingers 491, 493) extending from busbar 408. The fingers extending from busbar 408 may intersect with the fingers of IDT 422 extending from busbar 410. The length of the fingers extending from busbar 408 increases as each finger moves closer to side 458 of IDT 422.

[0059] As shown in the figure, reflector 402 is disposed adjacent to side 452 of IDT 420, opposite to side 462, and reflector 412 is disposed adjacent to side 462 of IDT 420. The length of reflector 402 at side 450 can be the same as the length of IDT 420 at side 452, and the length of reflector 412 at side 464 can be the same as the length of IDT 420 at side 462. The length of reflector 402 at side 450 can be greater than the length of reflector 412 at side 464.

[0060] Similarly, reflector 404 is disposed adjacent to side 456 of IDT 422 and opposite side 458, and reflector 414 is disposed adjacent to side 458 of IDT 422. The length of reflector 404 at side 454 can be the same as the length of IDT 422 at side 456, and the length of reflector 414 at side 460 can be the same as the length of IDT 422 at side 458. The length of reflector 404 at side 454 can be less than the length of reflector 414 at side 460.

[0061] Optionally, multiple stubs can be formed protruding from each of the busbars 406, 410, and 408. For example, as shown, a stub 499 protruding from busbar 406 can be optionally formed. Multiple stubs can be formed to reduce diffraction loss. Although Figure 4A The stub is shown in the figure, but it should be understood that other implementations may not include the stub.

[0062] Figure 4B The illustration shows an electroacoustic device 400 implemented using alternating orientations according to certain aspects of this disclosure. For example, as the finger is closer to the side 452 of the IDT (as shown in the figure), Figure 4B As shown on the right side, the length of the fingers in the IDT 420 increases. Conversely, as the fingers move closer to the right side of the IDT, Figure 4A The length of the finger portion of the IDT 420 in the electroacoustic device 400 is reduced. Similarly, in Figure 4B In the middle, when the finger is closer to side 456 of IDT 422 (e.g. Figure 4B When shown on the right side, the length of the fingers of IDT422 decreases.

[0063] Figure 5 An electroacoustic device 500 with four cascaded SAW resonators according to certain aspects of this disclosure is illustrated. While examples of two and four cascaded SAW resonators are described herein for ease of understanding, the aspects described herein can be implemented with any number of cascaded SAW resonators. As shown, the electroacoustic device 500 includes an IDT 420 located between bus 406 and bus 410, and an IDT 422 located between bus 410 and bus 408. As described, bus 410 may be angled relative to bus 406 or bus 408. As shown, the electroacoustic device 500 may also include an IDT 502 disposed between bus 408 and bus 504, and an IDT 506, a transmitter 504, and bus 508 disposed between the buses. Bus 504 may be angled relative to bus 408 or bus 508. Reflectors 510 and 512 may be disposed adjacent to opposite sides of IDT 502 to form SAW resonators. Reflectors 514 and 516 can be positioned on opposite sides of adjacent IDT 506 to form another SAW resonator, as shown. Therefore, the electroacoustic device 500 includes four SAW resonators cascaded in series: a first resonator with IDT 420, a second SAW resonator with IDT 422, a third SAW resonator with IDT 502, and a fourth SAW resonator with IDT 506.

[0064] Figure 6 The illustrations show that certain aspects of this disclosure may include... Figure 5A schematic diagram of an electroacoustic filter circuit 600 for an electroacoustic device 500. The filter circuit 600 provides an example using the disclosed SAW device. The filter circuit 600 includes an input terminal 602 and an output terminal 614. A ladder network of SAW resonators is provided between the input terminal 602 and the output terminal 614. The filter circuit 600 includes a first SAW resonator 604, a second SAW resonator 606, a third SAW resonator 608, and a fourth SAW resonator 609, all electrically connected in series between the input terminal 602 and the output terminal 614. A fifth SAW resonator 610 (e.g., a shunt resonator) has a first terminal connected between the first SAW resonator 604 and the second SAW resonator 606, and a second terminal connected to a reference potential node 630 (e.g., electrically grounded) of the filter circuit 600. The sixth SAW resonator 612 (e.g., a shunt resonator) has a first terminal connected between the second SAW resonator 606 and the third SAW resonator 608, and a second terminal connected to the reference potential node 630. The seventh SAW resonator 613 (e.g., a shunt resonator) has a first terminal connected between the third SAW resonator 608 and the fourth SAW resonator 609, and a second terminal connected to the reference potential node 630.

[0065] Each of the SAW resonators 604, 606, 608, 609, 610, 612, and 613 can be described as follows: Figure 5 The electroacoustic device 500 is described in the implementation. That is, each of the SAW resonators 604, 606, 608, 609, 610, 612, and 613 may include multiple (e.g., four) cascaded SAW resonators, as described in the section on... Figure 5 As described. For example, SAW resonator 604 may include a first SAW resonator formed by IDT 420 coupled between buses 406 and 410, a second SAW resonator formed by IDT 422 coupled between buses 410 and 408, a third SAW resonator formed by IDT 502 coupled between buses 408 and 504, and a fourth SAW resonator formed by IDT 506 coupled between buses 504 and 508. As described, buses 410 and 504 may be angled relative to buses 406, 408, and 508 to facilitate the formation of apodized IDTs as described.

[0066] In some implementations, each of the SAW resonators 604, 606, 608, 609, 610, 612, and 613 can be implemented using two cascaded SAW resonators (such as a first SAW resonator formed using IDT 420 coupled between buses 406 and 410, and a second SAW resonator formed using IDT 422 coupled between buses 410 and 408). The electroacoustic filter circuit 600 can, for example, be a bandpass filter circuit with a passband having a selected frequency range (e.g., on the order of 500 MHz and 6 GHz).

[0067] Figure 7 This is an example layout 700 of an electroacoustic filter circuit 600 according to certain aspects of this disclosure. Each of the SAW resonators 604, 606, 608, 609, 610, 612, and 613 can be implemented using four cascaded apodizer resonators, as per [reference to...]. Figure 5 As described. As shown in the figure, regarding Figure 6 In the described configuration, various traces can be used to couple SAW resonators 604, 606, 608, 609, 610, 612, and 613. For example, trace 702 can be used to couple SAW resonator 604 to SAW resonators 610 and 606, and trace 704 can be used to couple SAW resonator 610 to reference potential node 630.

[0068] Figure 8 This is a flowchart depicting an example operation 800 for signal processing according to certain aspects of this disclosure. For example, operation 800 may be performed by an electroacoustic device such as electroacoustic device 400 or 500.

[0069] Operation 800 may begin at block 805, where the electroacoustic device receives a signal at a first bus (e.g., bus 406) and processes the signal at block 810 via a first SAW resonator (e.g., SAW resonator 430) and a second SAW resonator (e.g., SAW resonator 432). As described in more detail here, the first SAW resonator may include an apodization IDT implemented between the first and second buses (e.g., bus 410), and the second SAW resonator may include an apodization IDT implemented between the second and third buses (e.g., bus 406). At block 815, the electroacoustic device may provide the processed signal at the third bus.

[0070] As described herein, an electroacoustic device may include a first SAW resonator comprising a first apodization IDT (e.g., IDT 420) disposed between a first bus (e.g., bus 406) and a second bus (e.g., bus 410). In other words, the first apodization IDT may include fingers disposed between the first and second buses. The electroacoustic device may also include a second SAW resonator comprising a second apodization IDT (e.g., IDT 422) disposed between a second bus and a third bus (e.g., bus 406). In other words, the second apodization IDT may include fingers disposed between the second and third buses. The second bus may be angled relative to at least one of the first or third buses.

[0071] In some respects, the first busbar may be parallel to the third busbar. In some respects, the first apodization IDT and the second apodization IDT are asymmetrical with respect to the center line between the first SAW resonator and the second SAW resonator.

[0072] In some aspects, the length of a first side (e.g., side 452) of the first apodization IDT may be greater than the length of a second side (e.g., side 462) of the first apodization IDT, the first side and the second side being opposite sides of the first apodization IDT. Furthermore, the length of a first side (e.g., side 456) of the second apodization IDT may be less than the length of a second side (e.g., side 458) of the second apodization IDT, the first side and the second side being opposite sides of the second apodization IDT. In some aspects, the second busbar may be longer than the first busbar and the third busbar, and the ends of the first busbar, the second busbar, and the third busbar may be aligned on each side of the first busbar, the second busbar, and the third busbar (e.g., aligned within a tolerance of twice the distance between adjacent fingers such as the first or second apodization IDT).

[0073] In some aspects, the first apodization IDT may include a first set of fingers (e.g., fingers 470, 472) extending from the second busbar. The length of the first set of fingers may decrease as each finger of the first set of fingers moves closer to one side of the first apodization IDT (e.g., side 462). The second apodization IDT may include a second set of fingers (e.g., fingers 480, 482) extending from the second busbar. The length of the second set of fingers may increase as each finger of the second set of fingers moves closer to one side of the second apodization IDT (e.g., side 458).

[0074] In some aspects, the first apodization IDT may include a third set of fingers (e.g., fingers 490, 492) extending from the first busbar, the third set of fingers intersecting the first set of fingers. The length of the third set of fingers may decrease as each finger of the third set moves closer to one side of the first apodization IDT (e.g., side 462). In some aspects, the second apodization IDT may include a fourth set of fingers (e.g., fingers 490, 492) extending from the third busbar, the fourth set of fingers intersecting the second set of fingers. The length of the fourth set of fingers may increase as each finger of the fourth set moves closer to one side of the second apodization IDT (e.g., side 458).

[0075] In some aspects, the first SAW resonator may include a first reflector (e.g., reflector 402) and a second reflector (e.g., reflector 412), the first reflector having a side (e.g., side 450) adjacent to a first side (e.g., side 452) of the first apodization IDT, and the second reflector having a side (e.g., side 464) adjacent to a second side (e.g., side 462) of the first apodization IDT, the first side and the second side being opposite sides of the first apodization IDT. The length of one side of the first reflector may differ from the length of the second side of the first apodization IDT, and the length of one side of the second reflector may differ from the length of the first side of the first apodization IDT. In some aspects, the second SAW resonator may include a third reflector (e.g., reflector 404) and a fourth reflector (e.g., reflector 414), the third reflector having a side (e.g., side 454) adjacent to a first side (e.g., side 456) of the second apodization IDT, and the fourth reflector having a side (e.g., side 460) adjacent to a second side (e.g., side 458) of the second apodization IDT, the first side and the second side being opposite sides of the second apodization IDT. The length of the side of the third reflector may differ from the length of the second side of the second apodization IDT, and the length of the side of the fourth reflector may differ from the length of the first side of the second apodization IDT. In some aspects, the length of one side of the first reflector may be greater than the length of one side of the second reflector.

[0076] In some aspects, the angle between the second bus and at least one of the first or third bus is greater than 0 degrees and less than or equal to 45 degrees. In some aspects, the electroacoustic device may include a third SAW resonator and a fourth SAW resonator, the third SAW resonator having a third apodization IDT disposed between the third bus (e.g., bus 406) and the fourth bus (e.g., bus 504), and the fourth SAW resonator having a fourth apodization IDT disposed between the fourth bus and the fifth bus (e.g., bus 508), such that the first, second, third, and fourth SAW resonators are cascaded. In some aspects, the fourth bus may be angled relative to at least one of the third or fifth bus. In some aspects, the angle of the fourth bus relative to the third bus may be the same as the angle of the second bus relative to the third bus.

[0077] In some aspects, a first apodization IDT and a second apodization IDT are disposed over at least one piezoelectric layer (e.g., piezoelectric material 102 or 302). In some aspects, at least one piezoelectric layer is disposed between a substrate and at least one of the first apodization IDT and the second apodization IDT. In some aspects, the substrate may include a substrate layer (e.g., substrate sublayer 310-1), a charge trapping layer (e.g., rich trapping layer 310-2), and a compensation layer (e.g., compensation layer 310-3), the charge trapping layer and the compensation layer being disposed between the substrate layer and at least one piezoelectric layer.

[0078] Figure 9 This is a flowchart depicting an example operation 900 for signal processing according to certain aspects of this disclosure. For example, operation 900 may be performed by an electroacoustic device such as electroacoustic device 400 or 500.

[0079] Operation 900 begins at block 905, where the electroacoustic device receives a signal at a first bus (e.g., bus 406) and processes the signal at block 910 via a first SAW resonator (e.g., SAW resonator 430) and a second SAW resonator (e.g., SAW resonator 432). The first SAW resonator may include a first IDT (e.g., IDT 420) disposed between the first bus (e.g., bus 406) and the second bus (e.g., bus 410). The second SAW resonator may include a second IDT (e.g., IDT 422) disposed between the second bus and a third bus (e.g., bus 408). The second bus is at an angle relative to at least one of the first bus or the third bus. The first IDT may include a first set of fingers (e.g., fingers 470, 472) extending from the second bus, wherein the length of the first set of fingers decreases as each of the first set of fingers moves closer to one side (e.g., side 452) of the first IDT. At frame 915, the electroacoustic device provides a processed signal at the third bus.

[0080] Figure 10 This is one of the options that can be adopted. Figure 6 This is a functional block diagram of at least a portion of an example of a simplified wireless transceiver circuit 1000, with filter circuitry 600. The transceiver circuitry 1000 is configured to receive a signal / information (shown as in-phase (I) and quadrature (Q) values) for transmission provided to one or more baseband (BB) filters 1012. The filtered output is provided to one or more mixers 1014 for up-conversion to a radio frequency (RF) signal. The output from the one or more mixers 1014 can be provided to a driver amplifier (DA) 1016, the output of which can be provided to a power amplifier (PA) 1018 to generate an amplified signal for transmission. The amplified signal is output to an antenna 1022 via one or more filters 1020 (e.g., duplexers, if used as frequency division duplex transceivers or other filters). The one or more filters 1020 may include... Figure 6 The filter circuit 600.

[0081] Antenna 1022 can be used to wirelessly transmit and receive data. Transceiver circuitry 1000 includes a receive path via one or more filters 1020, which is then fed to a low-noise amplifier (LNA) 1024 and another filter 1026, before being down-converted from the receive frequency to the baseband frequency via one or more mixer circuits 1028 before the signal is further processed (e.g., fed to an analog-to-digital converter (ADC) and then demodulated in the digital domain or otherwise processed). A separate filter 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 6 The filter circuit 600 is used to implement this.

[0082] Figure 11 This is a diagram of an environment 1100 including electronic device 1102, in which various aspects of this disclosure can be implemented. In environment 1100, electronic device 1102 communicates with base station 1104 via wireless link 1106. As shown, electronic device 1102 is depicted as a smartphone. However, electronic device 1102 can be implemented as any suitable computing or other electronic device, such as a 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 appliance, vehicle-based communication system, Internet of Things (IoT) device, sensor or security device, asset tracker, etc.

[0083] Base station 1104 communicates with electronic device 1102 via wireless link 1106, which can be implemented as any suitable type of wireless link. Although depicted as a base station tower in a cellular radio network, base station 1104 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, and other electronic devices typically described above. Therefore, electronic device 1102 can communicate with base station 1104 or another device via a wired connection, a wireless connection, or a combination thereof. Wireless link 1106 can include a downlink transmitting data or control information from base station 1104 to electronic device 1102 and an uplink transmitting other data or control information from electronic device 1102 to base station 1104. Wireless link 1106 can be implemented using any suitable communication protocol or standard, such as 3GPP LTE, 3GPP NR 5G, IEEE 802.11, IEEE 802.16, and Bluetooth. TM wait.

[0084] Electronic device 1102 includes processor 1180 and memory 1182. Memory 1182 may be or form part of a computer-readable storage medium. Processor 1180 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 1182. Memory 1182 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 1182 is implemented to store instructions 1184, data 1186, and other information of electronic device 1102, and therefore, when configured as a computer-readable storage medium or part thereof, memory 1182 does not include transient propagation signals or carrier waves.

[0085] Electronic device 1102 may also include an input / output port 1190. The I / O port 1190 enables data exchange or interaction with other devices, networks, or users, or between components of the device.

[0086] Electronic device 1102 may also include signal processor (SP) 1192 (e.g., digital signal processor (DSP)). Signal processor 1192 may function similarly to a processor and is capable of executing instructions and / or processing information in conjunction with memory 1182.

[0087] For communication purposes, electronic device 1102 also includes a modem 1194, a wireless transceiver 1196, and an antenna (not shown). The wireless transceiver 1196 provides connectivity to a given network and other connected electronic devices using radio frequency (RF) wireless signals, and may include... Figure 10 The transceiver circuit 1000. The wireless transceiver 1196 can facilitate communication over any suitable type of wireless network (e.g., wireless local area network (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)).

[0088] The various operations described above can be performed by any suitable device capable of performing the corresponding functions. 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.

[0089] As an example, any element, any portion of an element, or any combination of elements described herein can 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, gate logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionalities described throughout this invention. One or more processors in a processing system can execute software. Software should be interpreted broadly as instructions, instruction sets, code, code segments, program code, programs, subroutines, software components, application programs, software applications, software packages, routines, subroutines, objects, executable programs, threads of execution, procedures, functions, etc., whether or not referred to as software, firmware, middleware, microcode, hardware description languages, or other names.

[0090] Typically, in the case of the operations shown in the figure, these operations may have corresponding devices plus functional components with similar numbers.

[0091] As used herein, the term "determine" encompasses a variety of actions. For example, "determine" can include calculation, operation, processing, derivation, investigation, searching (e.g., searching in a table, database, or other data structure), ascertainment, etc. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), etc. Additionally, "determine" can include parsing, selecting, picking, building, etc.

[0092] In this disclosure, the term “exemplary” is used to mean “serving as an example, illustration, or description.” Any implementation or aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects of the invention. Similarly, the term “aspect” does not require that all aspects of this disclosure include the features, advantages, or modes of operation discussed. The term “coupling” as used herein refers to direct or indirect coupling between two objects. For example, if object A physically touches object B and object B touches object C, objects A and C can still be considered coupled to each other—even if objects A and C do not directly and physically touch each other. For example, a first object can be coupled to a second object even if the first object never directly and physically contacts the second object. The terms “circuit” and “circuit system” are used broadly and are intended to include hardware implementations of electrical devices and conductors that, when connected and configured, enable the implementation of the functions described in this disclosure, and are not limited to types of electronic circuits.

[0093] The accompanying drawings illustrate the apparatus and methods described in the detailed description by way of various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as “elements”). For example, these elements can be implemented using hardware.

[0094] One or more of the components, steps, features, and / or functions shown herein may be rearranged and / or combined into a single component, step, feature, or function, or embodied as several components, steps, or functions. Additional elements, components, steps, and / or functions may also be added without departing from the features disclosed herein. The devices, apparatuses, and / or components described herein may be configured to perform one or more of the methods, features, or steps described herein.

[0095] It should be understood that the specific order or hierarchy of steps in the disclosed method is an illustration of an exemplary process. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the method may be rearranged. The appended method claims present the elements of the various steps in a sample order and are not intended to limit one to the specific order or hierarchy presented, unless specifically stated therein.

[0096] The preceding description is provided to enable those skilled in the art to implement the various aspects described herein. Various modifications to these aspects will readily be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are to be consistent with the full scope of the language of the claims, wherein reference to an element in the singular form, unless expressly stated otherwise, is not intended to mean “one and only one,” but rather “one or more.” Unless otherwise specifically stated, the term “some” means one or more. The phrase “at least one” in the list of references to items refers to any combination of those items, including a single member. As an example, “at least one of the following: a, b, or c” is intended to cover at least: a, b, c, ab, ac, bc, and abc, and any combination having multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other order of a, b, and c). All structural and functional equivalents of the elements of the various aspects described throughout this disclosure are known or subsequently known. Elements of ordinary skill in the art are expressly incorporated herein by reference and are intended to be included in the claims. Furthermore, nothing disclosed herein is intended to be offered to the public, regardless of whether such disclosure is expressly stated in the claims. Claim elements should not be interpreted in accordance with 35 U.S.SC §112(f) unless the element is expressly stated using the phrase “component for…” or, in the case of a method claim, using the phrase “step for…”.

[0097] 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 methods and apparatus described above without departing from the scope of the claims.

Claims

1. An electroacoustic device, comprising: The first surface acoustic wave (SAW) resonator includes a first apodization interdigital transducer (IDT) disposed between the first bus and the second bus. as well as The second SAW resonator includes a second apodization IDT disposed between the second bus and the third bus, wherein the second bus is angled relative to at least one of the first bus or the third bus; The first apodization IDT includes a first set of fingers extending from the second busbar, and the length of the first set of fingers decreases as each finger of the first set of fingers gets closer to one side of the first apodization IDT. The second apodization IDT includes a second set of fingers extending from the second busbar, wherein the length of the second set of fingers increases as each finger of the second set of fingers moves closer to one side of the second apodization IDT.

2. The electroacoustic device according to claim 1, wherein: The length of the first side of the first apodization IDT is greater than the length of the second side of the first apodization IDT, and the first side and the second side are opposite sides of the first apodization IDT; and The length of the first side of the second apodization IDT is less than the length of the second side of the second apodization IDT, and the first side and the second side of the second apodization IDT are opposite sides of the second apodization IDT.

3. The electroacoustic device according to claim 1, wherein the second busbar is longer than the first busbar and the third busbar, and wherein the ends of the first busbar, the second busbar and the third busbar are aligned on each side of the first busbar, the second busbar and the third busbar.

4. The electroacoustic device according to claim 1, wherein: The first apodization IDT includes a third set of fingers extending from the first busbar, the third set of fingers intersecting with the first set of fingers; The length of the third set of fingers decreases as each finger of the third set of fingers gets closer to the side of the second apodization IDT; The second apodization IDT includes a fourth set of fingers extending from the third busbar, the fourth set of fingers intersecting the second set of fingers; and The length of the fourth set of fingers increases as each of the fourth set of fingers moves closer to one side of the second apodization IDT.

5. The electroacoustic device according to claim 1, wherein the first SAW resonator further comprises: A first reflector having a side adjacent to a first side of the first apodization IDT; as well as The second reflector has a side adjacent to the second side of the first apodization IDT, the first side and the second side being opposite sides of the first apodization IDT.

6. The electroacoustic device according to claim 5, wherein: The length of one side of the first reflector is different from the length of the second side of the first apodization IDT; and The length of one side of the second reflector is different from the length of the first side of the first apodization IDT.

7. The electroacoustic device according to claim 5, wherein the second SAW resonator further comprises: The third reflector has a side adjacent to the first side of the second apodization IDT; as well as The fourth reflector has a side adjacent to the second side of the second apodization IDT, wherein the first side and the second side of the second apodization IDT are opposite sides of the second apodization IDT.

8. The electroacoustic device according to claim 7, wherein: The length of one side of the third reflector is different from the length of the second side of the second apodization IDT; and The length of one side of the fourth reflector is different from the length of the first side of the second apodization IDT.

9. The electroacoustic device according to claim 5, wherein the length of one side of the first reflector is different from the length of one side of the second reflector.

10. The electroacoustic device according to claim 1, wherein the angle between the second bus and at least one of the first bus or the third bus is greater than 0 degrees and less than or equal to 45 degrees.

11. The electroacoustic device according to claim 1, further comprising: The third SAW resonator includes a third apodization IDT disposed between the third bus and the fourth bus; as well as The fourth SAW resonator includes a fourth apodization IDT disposed between the fourth bus and the fifth bus, such that the first SAW resonator, the second SAW resonator, the third SAW resonator and the fourth SAW resonator are cascaded, wherein the fourth bus is angled relative to at least one of the third bus or the fifth bus.

12. The electroacoustic device according to claim 11, wherein the angle of the fourth bus relative to the third bus is the same as the angle of the second bus relative to the third bus.

13. The electroacoustic device of claim 1, wherein the first apodization IDT and the second apodization IDT are disposed above at least one piezoelectric layer.

14. The electroacoustic device of claim 13, wherein the at least one piezoelectric layer is disposed between the substrate and at least one of the first apodization IDT and the second apodization IDT.

15. The electroacoustic device of claim 14, wherein the substrate comprises: Substrate layer; Charge trapping layer; as well as A compensation layer, wherein the charge trapping layer and the compensation layer are disposed between the substrate layer and the at least one piezoelectric layer.

16. The electroacoustic device according to claim 1, wherein the first busbar is parallel to the third busbar.

17. The electroacoustic device of claim 1, wherein the first apodization IDT and the second apodization IDT are asymmetrical with respect to the center line between the first SAW resonator and the second SAW resonator.

18. An electroacoustic device, comprising: The first surface acoustic wave (SAW) resonator includes a first interdigital transducer (IDT) disposed between the first bus and the second bus. as well as The second SAW resonator includes a second IDT disposed between a second bus and a third bus, wherein the second bus is angled relative to at least one of the first bus or the third bus, wherein the first IDT includes a first set of fingers extending from the second bus, and wherein the length of the first set of fingers decreases as each of the first set of fingers moves closer to one side of the first IDT. The second IDT includes a second set of fingers extending from the second busbar, and the length of the second set of fingers increases as each of the second set of fingers moves closer to one side of the second IDT, the side of the second IDT being on the same side of the electroacoustic device as the side of the first IDT.

19. The electroacoustic device according to claim 18, wherein: The first IDT includes a third set of fingers extending from the first busbar, the third set of fingers intersecting with the first set of fingers; The length of the third set of fingers decreases as each finger of the third set of fingers gets closer to one side of the first IDT; The second IDT includes a fourth set of fingers extending from the third busbar, the fourth set of fingers intersecting with the second set of fingers; and The length of the fourth set of fingers increases as each of the fourth set of fingers moves closer to one side of the second IDT.

20. The electroacoustic device of claim 18, wherein the second busbar is longer than the first busbar and the third busbar, and wherein the ends of the first busbar, the second busbar and the third busbar are aligned on each side of the first busbar, the second busbar and the third busbar.

21. The electroacoustic device of claim 18, wherein the first SAW resonator further comprises: A first reflector has a side adjacent to the side of the first IDT; as well as The second reflector has a side adjacent to the other side of the first IDT, the other side being opposite sides of the first IDT.

22. The electroacoustic device according to claim 21, wherein: The length of one side of the first reflector is different from the length of the other side of the first IDT; and The length of one side of the second reflector is different from the length of one side of the first IDT.

23. The electroacoustic device of claim 21, wherein the second SAW resonator further comprises: The third reflector has a side adjacent to the first side of the second IDT; as well as The fourth reflector has a side adjacent to the second side of the second IDT, wherein the first side and the second side of the second IDT are opposite sides of the second IDT.

24. The electroacoustic device according to claim 23, wherein: The length of the side of the third reflector is different from the length of the second side of the second IDT; and The length of the side of the fourth reflector is different from the length of the first side of the second IDT.

25. The electroacoustic device of claim 21, wherein the length of one side of the first reflector is different from the length of one side of the second reflector.

26. The electroacoustic device of claim 18, wherein the angle between the second bus and at least one of the first bus or the third bus is greater than 0 degrees and less than or equal to 45 degrees.

27. A method for signal processing, comprising: Receive signals at the first busbar; The signal is processed via a first surface acoustic wave (SAW) resonator and a second SAW resonator, wherein: The first SAW resonator includes a first apodization interdigital transducer (IDT) disposed between the first bus and the second bus; The second SAW resonator includes a second apodization IDT disposed between the second bus and the third bus; and The second busbar is at an angle relative to at least one of the first busbar or the third busbar; and The first apodization IDT includes a first set of fingers extending from the second busbar, and the length of the first set of fingers decreases as each finger of the first set of fingers gets closer to one side of the first apodization IDT. The second apodization IDT includes a second set of fingers extending from the second busbar, wherein the length of the second set of fingers increases as each finger of the second set of fingers moves closer to one side of the second apodization IDT. The processed signal is provided at the third bus.

28. A signal processing method, comprising: Receive signals at the first busbar; The signal is processed by a first surface acoustic wave (SAW) resonator and a second SAW resonator, wherein: The first SAW resonator includes a first interdigital transducer (IDT) disposed between the first bus and the second bus; The second SAW resonator includes a second IDT disposed between the second bus and the third bus; The second busbar is at an angle relative to at least one of the first busbar or the third busbar; The first IDT includes a first set of fingers extending from the second busbar; and The length of the first set of fingers decreases as each finger of the first set of fingers moves closer to the side of the first IDT; and The second IDT includes a second set of fingers extending from the second busbar; and The length of the second set of fingers increases as each finger in the second set of fingers moves closer to one side of the second IDT; and The processed signal is provided at the third bus.

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